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pranaygp/zeit-deployments

Snyk’s security scan found the following vulnerabilities.
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Vulnerabilities

 46 via 235 paths

Dependencies

 857

Source

 GitHub

Commit

 9ab566bd

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Severity
  • 2
  • 17
  • 24
  • 3
Status
  • 46
  • 0
  • 0

critical severity

Incomplete List of Disallowed Inputs

  • Vulnerable module: babel-traverse
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-react-remove-prop-types@0.4.8 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-es2015-modules-commonjs@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-computed-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-systemjs@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-helper-call-delegate@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-exponentiation-operator@6.24.1 › babel-helper-builder-binary-assignment-operator-visitor@6.24.1 › babel-helper-explode-assignable-expression@6.24.1 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0

…and 39 more

Overview

Affected versions of this package are vulnerable to Incomplete List of Disallowed Inputs when using plugins that rely on the path.evaluate() or path.evaluateTruthy() internal Babel methods.

Note:

This is only exploitable if the attacker uses known affected plugins such as @babel/plugin-transform-runtime, @babel/preset-env when using its useBuiltIns option, and any "polyfill provider" plugin that depends on @babel/helper-define-polyfill-provider. No other plugins under the @babel/ namespace are impacted, but third-party plugins might be.

Users that only compile trusted code are not impacted.

Workaround

Users who are unable to upgrade the library can upgrade the affected plugins instead, to avoid triggering the vulnerable code path in affected @babel/traverse.

Remediation

There is no fixed version for babel-traverse.

References

Incomplete List of Disallowed Inputs vulnerability report

critical severity

Improper Verification of Cryptographic Signature

  • Vulnerable module: elliptic
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › node-libs-browser@2.2.1 › crypto-browserify@3.12.1 › browserify-sign@4.2.3 › elliptic@6.6.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › node-libs-browser@2.2.1 › crypto-browserify@3.12.1 › create-ecdh@4.0.4 › elliptic@6.6.1

Overview

elliptic is a fast elliptic-curve cryptography implementation in plain javascript.

Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature due to an anomaly in the _truncateToN function. An attacker can cause legitimate transactions or communications to be incorrectly flagged as invalid by exploiting the signature verification process when the hash contains at least four leading 0 bytes, and the order of the elliptic curve's base point is smaller than the hash. In some situations, a private key exposure is possible. This can happen when an attacker knows a faulty and the corresponding correct signature for the same message.

PoC

var elliptic = require('elliptic'); // tested with version 6.5.7
var hash = require('hash.js');
var BN = require('bn.js');
var toArray = elliptic.utils.toArray;

var ec = new elliptic.ec('p192');
var msg = '343236343739373234';
var sig = '303502186f20676c0d04fc40ea55d5702f798355787363a91e97a7e50219009d1c8c171b2b02e7d791c204c17cea4cf556a2034288885b';
// Same public key just in different formats
var pk = '04cd35a0b18eeb8fcd87ff019780012828745f046e785deba28150de1be6cb4376523006beff30ff09b4049125ced29723';
var pkPem = '-----BEGIN PUBLIC KEY-----\nMEkwEwYHKoZIzj0CAQYIKoZIzj0DAQEDMgAEzTWgsY7rj82H/wGXgAEoKHRfBG54\nXeuigVDeG+bLQ3ZSMAa+/zD/CbQEkSXO0pcj\n-----END PUBLIC KEY-----\n';

// Create hash
var hashArray = hash.sha256().update(toArray(msg, 'hex')).digest();
// Convert array to string (just for showcase of the leading zeros)
var hashStr = Array.from(hashArray, function(byte) {
  return ('0' + (byte & 0xFF).toString(16)).slice(-2);
}).join('');
var hMsg = new BN(hashArray, 'hex');
// Hashed message contains 4 leading zeros bytes
console.log('sha256 hash(str): ' + hashStr);
// Due to using BN bitLength lib it does not calculate the bit length correctly (should be 32 since it is a sha256 hash)
console.log('Byte len of sha256 hash: ' + hMsg.byteLength());
console.log('sha256 hash(BN): ' + hMsg.toString(16));

// Due to the shift of the message to be within the order of the curve the delta computation is invalid
var pubKey = ec.keyFromPublic(toArray(pk, 'hex'));
console.log('Valid signature: ' + pubKey.verify(hashStr, sig));

// You can check that this hash should validate by consolidating openssl
const fs = require('fs');
fs.writeFile('msg.bin', new BN(msg, 16).toBuffer(), (err) => {
  if (err) throw err;
});
fs.writeFile('sig.bin', new BN(sig, 16).toBuffer(), (err) => {
  if (err) throw err;
});
fs.writeFile('cert.pem', pkPem, (err) => {
  if (err) throw err;
});

// To verify the correctness of the message signature and key one can run:
// openssl dgst -sha256 -verify cert.pem -signature sig.bin msg.bin
// Or run this python script
/*
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.asymmetric import ec


msg = '343236343739373234'
sig = '303502186f20676c0d04fc40ea55d5702f798355787363a91e97a7e50219009d1c8c171b2b02e7d791c204c17cea4cf556a2034288885b'
pk = '04cd35a0b18eeb8fcd87ff019780012828745f046e785deba28150de1be6cb4376523006beff30ff09b4049125ced29723'

p192 = ec.SECP192R1()
pk = ec.EllipticCurvePublicKey.from_encoded_point(p192, bytes.fromhex(pk))
pk.verify(bytes.fromhex(sig), bytes.fromhex(msg), ec.ECDSA(hashes.SHA256()))
*/

Remediation

There is no fixed version for elliptic.

References

Improper Verification of Cryptographic Signature vulnerability report

high severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: cross-spawn
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › cross-spawn@5.1.0
    Remediation: Upgrade to next@8.0.4.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › execa@0.8.0 › cross-spawn@5.1.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › yargs@8.0.2 › os-locale@2.1.0 › execa@0.7.0 › cross-spawn@5.1.0
    Remediation: Upgrade to next@10.0.6.

Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to improper input sanitization. An attacker can increase the CPU usage and crash the program by crafting a very large and well crafted string.

PoC

const { argument } = require('cross-spawn/lib/util/escape');
var str = "";
for (var i = 0; i < 1000000; i++) {
  str += "\\";
}
str += "◎";

console.log("start")
argument(str)
console.log("end")

// run `npm install cross-spawn` and `node attack.js` 
// then the program will stuck forever with high CPU usage

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade cross-spawn to version 6.0.6, 7.0.5 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

high severity

Information Disclosure

  • Vulnerable module: semantic-release
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3
    Remediation: Upgrade to next@5.0.0.

Overview

semantic-release is an Automated semver compliant package publishing

Affected versions of this package are vulnerable to Information Disclosure. Secrets that would normally be masked by semantic-release can be accidentally disclosed if they contain characters that become encoded when included in a URL.

Remediation

Upgrade semantic-release to version 17.2.3 or higher.

References

Information Disclosure vulnerability report

high severity

Prototype Pollution

  • Vulnerable module: ajv
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › ajv@5.5.2
    Remediation: Upgrade to next@7.0.0.

Overview

ajv is an Another JSON Schema Validator

Affected versions of this package are vulnerable to Prototype Pollution. A carefully crafted JSON schema could be provided that allows execution of other code by prototype pollution. (While untrusted schemas are recommended against, the worst case of an untrusted schema should be a denial of service, not execution of code.)

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade ajv to version 6.12.3 or higher.

References

Prototype Pollution vulnerability report

high severity

Remote Code Execution (RCE)

  • Vulnerable module: next
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3
    Remediation: Upgrade to next@5.1.0.

Overview

next is a react framework.

Affected versions of this package are vulnerable to Remote Code Execution (RCE) when the /path: route is used. An attacker can execute JavaScript code on the server by passing unsanitaized input to a require() call.

Remediation

Upgrade next to version 5.0.1-canary.5 or higher.

References

Remote Code Execution (RCE) vulnerability report

high severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: ansi-html
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › ansi-html@0.0.7
    Remediation: Upgrade to next@8.0.3.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack-hot-middleware@2.19.1 › ansi-html@0.0.7
    Remediation: Upgrade to next@9.3.4.

Overview

ansi-html is an An elegant lib that converts the chalked (ANSI) text to HTML.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). If an attacker provides a malicious string, it will get stuck processing the input for an extremely long time.

PoC

require('ansi-html')('x1b[0mx1b[' + '0'.repeat(35))

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade ansi-html to version 0.0.9 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

high severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: ansi-regex
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@9.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack-hot-middleware@2.19.1 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@9.3.4.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › friendly-errors-webpack-plugin@1.6.1 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › write-file-webpack-plugin@4.2.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › friendly-errors-webpack-plugin@1.6.1 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › write-file-webpack-plugin@4.2.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › friendly-errors-webpack-plugin@1.6.1 › string-length@1.0.1 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@7.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › yargs@8.0.2 › cliui@3.2.0 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@10.0.6.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-react-remove-prop-types@0.4.8 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-react-remove-prop-types@0.4.8 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › yargs@8.0.2 › cliui@3.2.0 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@10.0.6.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › npmlog@4.1.2 › gauge@2.7.4 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › yargs@8.0.2 › cliui@3.2.0 › wrap-ansi@2.1.0 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@10.0.6.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-es2015-modules-commonjs@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-es2015-modules-commonjs@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › npmlog@4.1.2 › gauge@2.7.4 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › yargs@8.0.2 › cliui@3.2.0 › wrap-ansi@2.1.0 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1
    Remediation: Upgrade to next@10.0.6.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/last-release-npm@2.0.2 › npmlog@4.1.2 › gauge@2.7.4 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-computed-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-systemjs@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-helper-call-delegate@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-transform-class-properties@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-block-scoping@6.26.0 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-computed-properties@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-systemjs@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-parameters@6.24.1 › babel-helper-call-delegate@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/last-release-npm@2.0.2 › npmlog@4.1.2 › gauge@2.7.4 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/last-release-npm@2.0.2 › npm-registry-client@8.6.0 › npmlog@4.1.2 › gauge@2.7.4 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-exponentiation-operator@6.24.1 › babel-helper-builder-binary-assignment-operator-visitor@6.24.1 › babel-helper-explode-assignable-expression@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-function-name@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-object-super@6.24.1 › babel-helper-replace-supers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-exponentiation-operator@6.24.1 › babel-helper-builder-binary-assignment-operator-visitor@6.24.1 › babel-helper-explode-assignable-expression@6.24.1 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/last-release-npm@2.0.2 › npm-registry-client@8.6.0 › npmlog@4.1.2 › gauge@2.7.4 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › babel-helpers@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-async-to-generator@6.24.1 › babel-helper-remap-async-to-generator@6.24.1 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-classes@6.24.1 › babel-helper-define-map@6.26.0 › babel-helper-function-name@6.24.1 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › babel-plugin-transform-es2015-modules-umd@6.24.1 › babel-plugin-transform-es2015-modules-amd@6.24.1 › babel-plugin-transform-es2015-modules-commonjs@6.26.2 › babel-template@6.26.0 › babel-traverse@6.26.0 › babel-code-frame@6.26.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1

…and 102 more

Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to the sub-patterns [[\\]()#;?]* and (?:;[-a-zA-Z\\d\\/#&.:=?%@~_]*)*.

PoC

import ansiRegex from 'ansi-regex';

for(var i = 1; i <= 50000; i++) {
    var time = Date.now();
    var attack_str = "\u001B["+";".repeat(i*10000);
    ansiRegex().test(attack_str)
    var time_cost = Date.now() - time;
    console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
}

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade ansi-regex to version 3.0.1, 4.1.1, 5.0.1, 6.0.1 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

high severity

Excessive Platform Resource Consumption within a Loop

  • Vulnerable module: braces
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › braces@2.3.2
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › braces@2.3.2
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › braces@2.3.2

Overview

braces is a Bash-like brace expansion, implemented in JavaScript.

Affected versions of this package are vulnerable to Excessive Platform Resource Consumption within a Loop due improper limitation of the number of characters it can handle, through the parse function. An attacker can cause the application to allocate excessive memory and potentially crash by sending imbalanced braces as input.

PoC

const { braces } = require('micromatch');

console.log("Executing payloads...");

const maxRepeats = 10;

for (let repeats = 1; repeats <= maxRepeats; repeats += 1) {
  const payload = '{'.repeat(repeats*90000);

  console.log(`Testing with ${repeats} repeats...`);
  const startTime = Date.now();
  braces(payload);
  const endTime = Date.now();
  const executionTime = endTime - startTime;
  console.log(`Regex executed in ${executionTime / 1000}s.\n`);
}

Remediation

Upgrade braces to version 3.0.3 or higher.

References

Excessive Platform Resource Consumption within a Loop vulnerability report

high severity

Prototype Pollution

  • Vulnerable module: loader-utils
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › loader-utils@1.1.0
    Remediation: Upgrade to next@10.0.6.

Overview

Affected versions of this package are vulnerable to Prototype Pollution in parseQuery function via the name variable in parseQuery.js. This pollutes the prototype of the object returned by parseQuery and not the global Object prototype (which is the commonly understood definition of Prototype Pollution). Therefore, the actual impact will depend on how applications utilize the returned object and how they filter unwanted keys.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade loader-utils to version 1.4.1, 2.0.3 or higher.

References

Prototype Pollution vulnerability report

high severity

Inefficient Regular Expression Complexity

  • Vulnerable module: micromatch
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10

Overview

Affected versions of this package are vulnerable to Inefficient Regular Expression Complexity due to the use of unsafe pattern configurations that allow greedy matching through the micromatch.braces() function. An attacker can cause the application to hang or slow down by passing a malicious payload that triggers extensive backtracking in regular expression processing.

Remediation

Upgrade micromatch to version 4.0.8 or higher.

References

Inefficient Regular Expression Complexity vulnerability report

high severity

Arbitrary File Read

  • Vulnerable module: next
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3
    Remediation: Upgrade to next@5.1.0.

Overview

next is a react framework.

Affected versions of this package are vulnerable to Arbitrary File Read. The /path: route fails to properly sanitize input and passes it to a require() call. This allows attackers to execute JavaScript code on the server.

Remediation

Upgrade next to version 5.1.0 or higher.

References

Arbitrary File Read vulnerability report

high severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: semver
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › npmconf@2.1.3 › semver@4.3.6

Overview

semver is a semantic version parser used by npm.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the function new Range, when untrusted user data is provided as a range.

PoC


const semver = require('semver')
const lengths_2 = [2000, 4000, 8000, 16000, 32000, 64000, 128000]

console.log("n[+] Valid range - Test payloads")
for (let i = 0; i =1.2.3' + ' '.repeat(lengths_2[i]) + '<1.3.0';
const start = Date.now()
semver.validRange(value)
// semver.minVersion(value)
// semver.maxSatisfying(["1.2.3"], value)
// semver.minSatisfying(["1.2.3"], value)
// new semver.Range(value, {})

const end = Date.now();
console.log('length=%d, time=%d ms', value.length, end - start);
}

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade semver to version 5.7.2, 6.3.1, 7.5.2 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

high severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: ssri
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/last-release-npm@2.0.2 › npm-registry-client@8.6.0 › ssri@5.3.0

Overview

ssri is a Standard Subresource Integrity library -- parses, serializes, generates, and verifies integrity metadata according to the SRI spec.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). ssri processes SRIs using a regular expression which is vulnerable to a denial of service. Malicious SRIs could take an extremely long time to process, leading to denial of service. This issue only affects consumers using the strict option.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade ssri to version 6.0.2, 7.1.1, 8.0.1 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

high severity

Denial of Service (DoS)

  • Vulnerable module: trim-newlines
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/commit-analyzer@3.0.7 › conventional-commits-parser@2.1.7 › meow@4.0.1 › trim-newlines@2.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › conventional-commits-parser@2.1.7 › meow@4.0.1 › trim-newlines@2.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › git-raw-commits@1.3.6 › meow@4.0.1 › trim-newlines@2.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › git-semver-tags@1.3.6 › meow@4.0.1 › trim-newlines@2.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › dateformat@1.0.12 › meow@3.7.0 › trim-newlines@1.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › conventional-changelog-writer@2.0.3 › meow@3.7.0 › trim-newlines@1.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › get-pkg-repo@1.4.0 › meow@3.7.0 › trim-newlines@1.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › conventional-changelog-writer@2.0.3 › dateformat@1.0.12 › meow@3.7.0 › trim-newlines@1.0.0
    Remediation: Upgrade to next@5.0.0.

…and 5 more

Overview

trim-newlines is a Trim newlines from the start and/or end of a string

Affected versions of this package are vulnerable to Denial of Service (DoS) via the end() method.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade trim-newlines to version 3.0.1, 4.0.1 or higher.

References

Denial of Service (DoS) vulnerability report

high severity

Prototype Pollution

  • Vulnerable module: unset-value
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › braces@2.3.2 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › braces@2.3.2 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › braces@2.3.2 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › extglob@2.0.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › extglob@2.0.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › nanomatch@1.2.13 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › nanomatch@1.2.13 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › anymatch@2.0.0 › micromatch@3.1.10 › extglob@2.0.4 › expand-brackets@2.1.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › readdirp@2.2.1 › micromatch@3.1.10 › extglob@2.0.4 › expand-brackets@2.1.4 › snapdragon@0.8.2 › base@0.11.2 › cache-base@1.0.1 › unset-value@1.0.0

…and 8 more

Overview

Affected versions of this package are vulnerable to Prototype Pollution via the unset function in index.js, because it allows access to object prototype properties.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade unset-value to version 2.0.1 or higher.

References

Prototype Pollution vulnerability report

high severity

Path Traversal

  • Vulnerable module: webpack-dev-middleware
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack-dev-middleware@1.12.0
    Remediation: Upgrade to next@9.3.4.

Overview

Affected versions of this package are vulnerable to Path Traversal due to insufficient validation of the supplied URL address before returning the local file. This issue allows accessing any file on the developer's machine. The middleware can operate with either the physical filesystem or a virtualized in-memory memfs filesystem. When the writeToDisk configuration option is set to true, the physical filesystem is utilized. The getFilenameFromUrl method parses the URL and constructs the local file path by stripping the public path prefix from the URL and appending the unescaped path suffix to the outputPath. Since the URL is not unescaped and normalized automatically before calling the middleware, it is possible to use %2e and %2f sequences to perform a path traversal attack.

Notes:

  1. This vulnerability is exploitable without any specific configurations, allowing an attacker to access and exfiltrate content from any file on the developer's machine.

  2. If the development server is exposed on a public IP address or 0.0.0.0, an attacker on the local network can access the files without victim interaction.

  3. If the server permits access from third-party domains, a malicious link could lead to local file exfiltration when visited by the victim.

PoC

A blank project can be created containing the following configuration file webpack.config.js:

module.exports = { devServer: { devMiddleware: { writeToDisk: true } } };

When started, it is possible to access any local file, e.g. /etc/passwd:

$ curl localhost:8080/public/..%2f..%2f..%2f..%2f../etc/passwd

root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin

Remediation

Upgrade webpack-dev-middleware to version 5.3.4, 6.1.2, 7.1.0 or higher.

References

Path Traversal vulnerability report

high severity

Improper Handling of Extra Parameters

  • Vulnerable module: follow-redirects
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › github@12.1.0 › follow-redirects@1.2.6
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/condition-travis@6.2.1 › github@12.1.0 › follow-redirects@1.2.6

Overview

Affected versions of this package are vulnerable to Improper Handling of Extra Parameters due to the improper handling of URLs by the url.parse() function. When new URL() throws an error, it can be manipulated to misinterpret the hostname. An attacker could exploit this weakness to redirect traffic to a malicious site, potentially leading to information disclosure, phishing attacks, or other security breaches.

PoC

# Case 1 : Bypassing localhost restriction
let url = 'http://[localhost]/admin';
try{
    new URL(url); // ERROR : Invalid URL
}catch{
    url.parse(url); // -> http://localhost/admin
}

# Case 2 : Bypassing domain restriction
let url = 'http://attacker.domain*.allowed.domain:a';
try{
    new URL(url); // ERROR : Invalid URL
}catch{
    url.parse(url); // -> http://attacker.domain/*.allowed.domain:a
}

Remediation

Upgrade follow-redirects to version 1.15.4 or higher.

References

Improper Handling of Extra Parameters vulnerability report

high severity

Code Injection

  • Vulnerable module: lodash.template
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › git-raw-commits@1.3.6 › lodash.template@4.5.0

Overview

lodash.template is a The Lodash method _.template exported as a Node.js module.

Affected versions of this package are vulnerable to Code Injection via template.

PoC

var _ = require('lodash');

_.template('', { variable: '){console.log(process.env)}; with(obj' })()

Remediation

There is no fixed version for lodash.template.

References

Code Injection vulnerability report

medium severity

Information Exposure

  • Vulnerable module: follow-redirects
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › github@12.1.0 › follow-redirects@1.2.6
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/condition-travis@6.2.1 › github@12.1.0 › follow-redirects@1.2.6

Overview

Affected versions of this package are vulnerable to Information Exposure due to the handling of the Proxy-Authorization header across hosts. When using a dependent library, it only clears the authorization header during cross-domain redirects but allows the proxy-authentication header, which contains credentials, to persist. This behavior may lead to the unintended leakage of credentials if an attacker can trigger a cross-domain redirect and capture the persistent proxy-authentication header.

PoC

const axios = require('axios');

axios.get('http://127.0.0.1:10081/',{
headers: {
'AuThorization': 'Rear Test',
'ProXy-AuthoriZation': 'Rear Test',
'coOkie': 't=1'
}
}).then(function (response) {
console.log(response);
})

Remediation

Upgrade follow-redirects to version 1.15.6 or higher.

References

Information Exposure vulnerability report

medium severity

Information Exposure

  • Vulnerable module: node-fetch
  • Introduced through: isomorphic-fetch@2.2.1 and next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
    Remediation: Upgrade to isomorphic-fetch@3.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › prop-types@15.6.0 › fbjs@0.8.18 › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
    Remediation: Upgrade to next@7.0.0.

Overview

node-fetch is a light-weight module that brings window.fetch to node.js

Affected versions of this package are vulnerable to Information Exposure when fetching a remote url with Cookie, if it get a Location response header, it will follow that url and try to fetch that url with provided cookie. This can lead to forwarding secure headers to 3th party.

Remediation

Upgrade node-fetch to version 2.6.7, 3.1.1 or higher.

References

Information Exposure vulnerability report

medium severity

Server-side Request Forgery (SSRF)

  • Vulnerable module: request
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › codeclimate-test-reporter@0.5.1 › request@2.88.2
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/last-release-npm@2.0.2 › npm-registry-client@8.6.0 › request@2.88.2

Overview

request is a simplified http request client.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) due to insufficient checks in the lib/redirect.js file by allowing insecure redirects in the default configuration, via an attacker-controller server that does a cross-protocol redirect (HTTP to HTTPS, or HTTPS to HTTP).

NOTE: request package has been deprecated, so a fix is not expected. See https://github.com/request/request/issues/3142.

Remediation

A fix was pushed into the master branch but not yet published.

References

Server-side Request Forgery (SSRF) vulnerability report

medium severity

Prototype Pollution

  • Vulnerable module: tough-cookie
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › codeclimate-test-reporter@0.5.1 › request@2.88.2 › tough-cookie@2.5.0
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/last-release-npm@2.0.2 › npm-registry-client@8.6.0 › request@2.88.2 › tough-cookie@2.5.0

Overview

tough-cookie is a RFC6265 Cookies and CookieJar module for Node.js.

Affected versions of this package are vulnerable to Prototype Pollution due to improper handling of Cookies when using CookieJar in rejectPublicSuffixes=false mode. Due to an issue with the manner in which the objects are initialized, an attacker can expose or modify a limited amount of property information on those objects. There is no impact to availability.

PoC

// PoC.js
async function main(){
var tough = require("tough-cookie");
var cookiejar = new tough.CookieJar(undefined,{rejectPublicSuffixes:false});
// Exploit cookie
await cookiejar.setCookie(
  "Slonser=polluted; Domain=__proto__; Path=/notauth",
  "https://__proto__/admin"
);
// normal cookie
var cookie = await cookiejar.setCookie(
  "Auth=Lol; Domain=google.com; Path=/notauth",
  "https://google.com/"
);

//Exploit cookie
var a = {};
console.log(a["/notauth"]["Slonser"])
}
main();

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade tough-cookie to version 4.1.3 or higher.

References

Prototype Pollution vulnerability report

medium severity

Prototype Pollution

  • Vulnerable module: json5
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › json5@0.5.1
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › loader-utils@1.1.0 › json5@0.5.1
    Remediation: Upgrade to next@9.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › json5@0.5.1
    Remediation: Upgrade to next@10.0.6.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-core@6.26.0 › babel-register@6.26.0 › babel-core@6.26.3 › json5@0.5.1

…and 1 more

Overview

Affected versions of this package are vulnerable to Prototype Pollution via the parse method , which does not restrict parsing of keys named __proto__, allowing specially crafted strings to pollute the prototype of the resulting object. This pollutes the prototype of the object returned by JSON5.parse and not the global Object prototype (which is the commonly understood definition of Prototype Pollution). Therefore, the actual impact will depend on how applications utilize the returned object and how they filter unwanted keys.

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade json5 to version 1.0.2, 2.2.2 or higher.

References

Prototype Pollution vulnerability report

medium severity

Prototype Pollution

  • Vulnerable module: dot-prop
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/commit-analyzer@3.0.7 › conventional-changelog-angular@1.6.6 › compare-func@1.3.4 › dot-prop@3.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-angular@1.6.6 › compare-func@1.3.4 › dot-prop@3.0.0
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › conventional-changelog-writer@2.0.3 › compare-func@1.3.4 › dot-prop@3.0.0
    Remediation: Upgrade to next@5.0.0.

Overview

dot-prop is a package to get, set, or delete a property from a nested object using a dot path.

Affected versions of this package are vulnerable to Prototype Pollution. It is possible for a user to modify the prototype of a base object.

PoC by aaron_costello

var dotProp = require("dot-prop")
const object = {};
console.log("Before " + object.b); //Undefined
dotProp.set(object, '__proto__.b', true);
console.log("After " + {}.b); //true

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade dot-prop to version 4.2.1, 5.1.1 or higher.

References

Prototype Pollution vulnerability report

medium severity

Missing Release of Resource after Effective Lifetime

  • Vulnerable module: inflight
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob@7.1.2 › inflight@1.0.6
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-plugin-module-resolver@2.7.1 › glob@7.2.3 › inflight@1.0.6
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › del@3.0.0 › globby@6.1.0 › glob@7.2.3 › inflight@1.0.6
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › del@3.0.0 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › mv@2.1.1 › rimraf@2.4.5 › glob@6.0.4 › inflight@1.0.6
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › recursive-copy@2.0.6 › del@2.2.2 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › recursive-copy@2.0.6 › del@2.2.2 › globby@5.0.0 › glob@7.2.3 › inflight@1.0.6

…and 4 more

Overview

Affected versions of this package are vulnerable to Missing Release of Resource after Effective Lifetime via the makeres function due to improperly deleting keys from the reqs object after execution of callbacks. This behavior causes the keys to remain in the reqs object, which leads to resource exhaustion.

Exploiting this vulnerability results in crashing the node process or in the application crash.

Note: This library is not maintained, and currently, there is no fix for this issue. To overcome this vulnerability, several dependent packages have eliminated the use of this library.

To trigger the memory leak, an attacker would need to have the ability to execute or influence the asynchronous operations that use the inflight module within the application. This typically requires access to the internal workings of the server or application, which is not commonly exposed to remote users. Therefore, “Attack vector” is marked as “Local”.

PoC

const inflight = require('inflight');

function testInflight() {
  let i = 0;
  function scheduleNext() {
    let key = `key-${i++}`;
    const callback = () => {
    };
    for (let j = 0; j < 1000000; j++) {
      inflight(key, callback);
    }

    setImmediate(scheduleNext);
  }


  if (i % 100 === 0) {
    console.log(process.memoryUsage());
  }

  scheduleNext();
}

testInflight();

Remediation

There is no fixed version for inflight.

References

Missing Release of Resource after Effective Lifetime vulnerability report

medium severity

Denial of Service

  • Vulnerable module: node-fetch
  • Introduced through: isomorphic-fetch@2.2.1 and next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
    Remediation: Upgrade to isomorphic-fetch@3.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › prop-types@15.6.0 › fbjs@0.8.18 › isomorphic-fetch@2.2.1 › node-fetch@1.7.3
    Remediation: Upgrade to next@7.0.0.

Overview

node-fetch is a light-weight module that brings window.fetch to node.js

Affected versions of this package are vulnerable to Denial of Service. Node Fetch did not honor the size option after following a redirect, which means that when a content size was over the limit, a FetchError would never get thrown and the process would end without failure.

Remediation

Upgrade node-fetch to version 2.6.1, 3.0.0-beta.9 or higher.

References

Denial of Service vulnerability report

medium severity

Cross-site Scripting (XSS)

  • Vulnerable module: webpack
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0
    Remediation: Upgrade to next@10.0.6.

Overview

Affected versions of this package are vulnerable to Cross-site Scripting (XSS) via DOM clobbering in the AutoPublicPathRuntimeModule class. Non-script HTML elements with unsanitized attributes such as name and id can be leveraged to execute code in the victim's browser. An attacker who can control such elements on a page that includes Webpack-generated files, can cause subsequent scripts to be loaded from a malicious domain.

PoC

<!DOCTYPE html>
<html>
<head>
  <title>Webpack Example</title>
  <!-- Attacker-controlled Script-less HTML Element starts--!>
  <img name="currentScript" src="https://attacker.controlled.server/"></img>
  <!-- Attacker-controlled Script-less HTML Element ends--!>
</head>
<script src="./dist/webpack-gadgets.bundle.js"></script>
<body>
</body>
</html>

Details

A cross-site scripting attack occurs when the attacker tricks a legitimate web-based application or site to accept a request as originating from a trusted source.

This is done by escaping the context of the web application; the web application then delivers that data to its users along with other trusted dynamic content, without validating it. The browser unknowingly executes malicious script on the client side (through client-side languages; usually JavaScript or HTML) in order to perform actions that are otherwise typically blocked by the browser’s Same Origin Policy.

Injecting malicious code is the most prevalent manner by which XSS is exploited; for this reason, escaping characters in order to prevent this manipulation is the top method for securing code against this vulnerability.

Escaping means that the application is coded to mark key characters, and particularly key characters included in user input, to prevent those characters from being interpreted in a dangerous context. For example, in HTML, < can be coded as &lt; and > can be coded as &gt; in order to be interpreted and displayed as themselves in text, while within the code itself, they are used for HTML tags. If malicious content is injected into an application that escapes special characters and that malicious content uses < and > as HTML tags, those characters are nonetheless not interpreted as HTML tags by the browser if they’ve been correctly escaped in the application code and in this way the attempted attack is diverted.

The most prominent use of XSS is to steal cookies (source: OWASP HttpOnly) and hijack user sessions, but XSS exploits have been used to expose sensitive information, enable access to privileged services and functionality and deliver malware.

Types of attacks

There are a few methods by which XSS can be manipulated:

Type Origin Description
Stored Server The malicious code is inserted in the application (usually as a link) by the attacker. The code is activated every time a user clicks the link.
Reflected Server The attacker delivers a malicious link externally from the vulnerable web site application to a user. When clicked, malicious code is sent to the vulnerable web site, which reflects the attack back to the user’s browser.
DOM-based Client The attacker forces the user’s browser to render a malicious page. The data in the page itself delivers the cross-site scripting data.
Mutated The attacker injects code that appears safe, but is then rewritten and modified by the browser, while parsing the markup. An example is rebalancing unclosed quotation marks or even adding quotation marks to unquoted parameters.

Affected environments

The following environments are susceptible to an XSS attack:

  • Web servers
  • Application servers
  • Web application environments

How to prevent

This section describes the top best practices designed to specifically protect your code:

  • Sanitize data input in an HTTP request before reflecting it back, ensuring all data is validated, filtered or escaped before echoing anything back to the user, such as the values of query parameters during searches.
  • Convert special characters such as ?, &, /, <, > and spaces to their respective HTML or URL encoded equivalents.
  • Give users the option to disable client-side scripts.
  • Redirect invalid requests.
  • Detect simultaneous logins, including those from two separate IP addresses, and invalidate those sessions.
  • Use and enforce a Content Security Policy (source: Wikipedia) to disable any features that might be manipulated for an XSS attack.
  • Read the documentation for any of the libraries referenced in your code to understand which elements allow for embedded HTML.

Remediation

Upgrade webpack to version 5.94.0 or higher.

References

Cross-site Scripting (XSS) vulnerability report

medium severity

Prototype Pollution

  • Vulnerable module: minimist
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › minimist@1.2.0
    Remediation: Upgrade to next@8.0.0.

Overview

minimist is a parse argument options module.

Affected versions of this package are vulnerable to Prototype Pollution. The library could be tricked into adding or modifying properties of Object.prototype using a constructor or __proto__ payload.

PoC by Snyk

require('minimist')('--__proto__.injected0 value0'.split(' '));
console.log(({}).injected0 === 'value0'); // true

require('minimist')('--constructor.prototype.injected1 value1'.split(' '));
console.log(({}).injected1 === 'value1'); // true

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade minimist to version 0.2.1, 1.2.3 or higher.

References

Prototype Pollution vulnerability report

medium severity

Prototype Pollution

  • Vulnerable module: yargs-parser
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › yargs@8.0.2 › yargs-parser@7.0.0
    Remediation: Upgrade to next@10.0.6.

Overview

yargs-parser is a mighty option parser used by yargs.

Affected versions of this package are vulnerable to Prototype Pollution. The library could be tricked into adding or modifying properties of Object.prototype using a __proto__ payload.

Our research team checked several attack vectors to verify this vulnerability:

  1. It could be used for privilege escalation.
  2. The library could be used to parse user input received from different sources:
    • terminal emulators
    • system calls from other code bases
    • CLI RPC servers

PoC by Snyk

const parser = require("yargs-parser");
console.log(parser('--foo.__proto__.bar baz'));
console.log(({}).bar);

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade yargs-parser to version 5.0.1, 13.1.2, 15.0.1, 18.1.1 or higher.

References

Prototype Pollution vulnerability report

medium severity

Open Redirect

  • Vulnerable module: got
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/condition-travis@6.2.1 › travis-deploy-once@3.3.0 › got@8.3.2

Overview

Affected versions of this package are vulnerable to Open Redirect due to missing verification of requested URLs. It allowed a victim to be redirected to a UNIX socket.

Remediation

Upgrade got to version 11.8.5, 12.1.0 or higher.

References

Open Redirect vulnerability report

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: browserslist
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › babel-preset-env@1.6.0 › browserslist@2.11.3

Overview

browserslist is a Share target browsers between different front-end tools, like Autoprefixer, Stylelint and babel-env-preset

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) during parsing of queries.

PoC by Yeting Li

var browserslist = require("browserslist")
function build_attack(n) {
    var ret = "> "
    for (var i = 0; i < n; i++) {
        ret += "1"
    }
    return ret + "!";
}

// browserslist('> 1%')

//browserslist(build_attack(500000))
for(var i = 1; i <= 500000; i++) {
    if (i % 1000 == 0) {
        var time = Date.now();
        var attack_str = build_attack(i)
        try{
            browserslist(attack_str);
            var time_cost = Date.now() - time;
            console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms");
            }
        catch(e){
        var time_cost = Date.now() - time;
        console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms");
        }
    }
}

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade browserslist to version 4.16.5 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: conventional-commits-parser
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/commit-analyzer@3.0.7 › conventional-commits-parser@2.1.7
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/release-notes-generator@4.0.5 › conventional-changelog-core@1.9.5 › conventional-commits-parser@2.1.7
    Remediation: Upgrade to next@5.0.0.

Overview

conventional-commits-parser is a Parse raw conventional commits

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to missing sanitization.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade conventional-commits-parser to version 3.2.3 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

medium severity

Information Exposure

  • Vulnerable module: follow-redirects
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › github@12.1.0 › follow-redirects@1.2.6
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/condition-travis@6.2.1 › github@12.1.0 › follow-redirects@1.2.6

Overview

Affected versions of this package are vulnerable to Information Exposure by leaking the cookie header to a third party site in the process of fetching a remote URL with the cookie in the request body. If the response contains a location header, it will follow the redirect to another URL of a potentially malicious actor, to which the cookie would be exposed.

Remediation

Upgrade follow-redirects to version 1.14.7 or higher.

References

Information Exposure vulnerability report

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: glob-parent
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › watchpack@1.7.5 › watchpack-chokidar2@2.0.1 › chokidar@2.1.8 › glob-parent@3.1.0

Overview

glob-parent is a package that helps extracting the non-magic parent path from a glob string.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). The enclosure regex used to check for strings ending in enclosure containing path separator.

PoC by Yeting Li

var globParent = require("glob-parent")
function build_attack(n) {
var ret = "{"
for (var i = 0; i < n; i++) {
ret += "/"
}

return ret;
}

globParent(build_attack(5000));

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade glob-parent to version 5.1.2 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: http-cache-semantics
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/condition-travis@6.2.1 › travis-deploy-once@3.3.0 › got@8.3.2 › cacheable-request@2.1.4 › http-cache-semantics@3.8.1

Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). The issue can be exploited via malicious request header values sent to a server, when that server reads the cache policy from the request using this library.

PoC

Run the following script in Node.js after installing the http-cache-semantics NPM package:

const CachePolicy = require("http-cache-semantics");

for (let i = 0; i <= 5; i++) {

const attack = "a" + " ".repeat(i * 7000) +
"z";

const start = performance.now();
new CachePolicy({
headers: {},
}, {
headers: {
"cache-control": attack,
},


});
console.log(`${attack.length}: ${performance.now() - start}ms`);
}

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade http-cache-semantics to version 4.1.1 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: loader-utils
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › loader-utils@1.1.0
    Remediation: Upgrade to next@10.0.6.

Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the resourcePath variable in interpolateName.js.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade loader-utils to version 1.4.2, 2.0.4, 3.2.1 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: loader-utils
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › loader-utils@1.1.0
    Remediation: Upgrade to next@10.0.6.

Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) in interpolateName function via the URL variable.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade loader-utils to version 1.4.2, 2.0.4, 3.2.1 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

medium severity

Resource Exhaustion

  • Vulnerable module: next
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3
    Remediation: Upgrade to next@13.5.0.

Overview

next is a react framework.

Affected versions of this package are vulnerable to Resource Exhaustion via the cache-control header. An attacker can cause a denial of service to all users requesting the same URL via a CDN by caching empty prefetch responses.

Remediation

Upgrade next to version 13.4.20-canary.13 or higher.

References

Resource Exhaustion vulnerability report

medium severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: uglify-js
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › uglifyjs-webpack-plugin@0.4.6 › uglify-js@2.8.29
    Remediation: Upgrade to next@10.0.6.

Overview

uglify-js is a JavaScript parser, minifier, compressor and beautifier toolkit.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the string_template and the decode_template functions.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

  • A The string must start with the letter 'A'
  • (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
  • D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

  1. CCC
  2. CC+C
  3. C+CC
  4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

String Number of C's Number of steps
ACCCX 3 38
ACCCCX 4 71
ACCCCCX 5 136
ACCCCCCCCCCCCCCX 14 65,553

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade uglify-js to version 3.14.3 or higher.

References

Regular Expression Denial of Service (ReDoS) vulnerability report

medium severity

Denial of Service (DoS)

  • Vulnerable module: mem
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › webpack@3.6.0 › yargs@8.0.2 › os-locale@2.1.0 › mem@1.1.0
    Remediation: Upgrade to next@10.0.6.

Overview

mem is an optimization used to speed up consecutive function calls by caching the result of calls with identical input.

Affected versions of this package are vulnerable to Denial of Service (DoS). Old results were deleted from the cache and could cause a memory leak.

details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade mem to version 4.0.0 or higher.

References

Denial of Service (DoS) vulnerability report

medium severity

Open Redirect

  • Vulnerable module: next
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3
    Remediation: Upgrade to next@11.1.0.

Overview

next is a react framework.

Affected versions of this package are vulnerable to Open Redirect. Specially encoded paths could be used when pages/_error.js was statically generated, allowing an open redirect to occur to an external site. In general, this redirect does not directly harm users, though it can allow for phishing attacks by redirecting to an attacker's domain from a trusted domain.

Remediation

Upgrade next to version 11.1.0 or higher.

References

Open Redirect vulnerability report

medium severity

Path Traversal

  • Vulnerable module: next
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3
    Remediation: Upgrade to next@9.3.2.

Overview

next is a react framework.

Affected versions of this package are vulnerable to Path Traversal. Next.js versions before 9.3.2 have a directory traversal vulnerability. Attackers could craft special requests to access files in the dist directory (.next). This does not affect files outside of the dist directory (.next).

Details:

A Directory Traversal attack (also known as path traversal) aims to access files and directories that are stored outside the intended folder. By manipulating files with "dot-dot-slash (../)" sequences and its variations, or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system, including application source code, configuration, and other critical system files.

Directory Traversal vulnerabilities can be generally divided into two types:

  • Information Disclosure: Allows the attacker to gain information about the folder structure or read the contents of sensitive files on the system.

st is a module for serving static files on web pages, and contains a vulnerability of this type. In our example, we will serve files from the public route.

If an attacker requests the following URL from our server, it will in turn leak the sensitive private key of the root user.

curl http://localhost:8080/public/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/root/.ssh/id_rsa

Note %2e is the URL encoded version of . (dot).

  • Writing arbitrary files: Allows the attacker to create or replace existing files. This type of vulnerability is also known as Zip-Slip.

One way to achieve this is by using a malicious zip archive that holds path traversal filenames. When each filename in the zip archive gets concatenated to the target extraction folder, without validation, the final path ends up outside of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.

The following is an example of a zip archive with one benign file and one malicious file. Extracting the malicious file will result in traversing out of the target folder, ending up in /root/.ssh/ overwriting the authorized_keys file:

2018-04-15 22:04:29 .....           19           19  good.txt
2018-04-15 22:04:42 .....           20           20  ../../../../../../root/.ssh/authorized_keys

Remediation

Upgrade next to version 9.3.2 or higher.

References

Path Traversal vulnerability report

low severity

Prototype Pollution

  • Vulnerable module: minimist
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › minimist@1.2.0
    Remediation: Upgrade to next@8.0.0.

Overview

minimist is a parse argument options module.

Affected versions of this package are vulnerable to Prototype Pollution due to a missing handler to Function.prototype.

Notes:

  • This vulnerability is a bypass to CVE-2020-7598

  • The reason for the different CVSS between CVE-2021-44906 to CVE-2020-7598, is that CVE-2020-7598 can pollute objects, while CVE-2021-44906 can pollute only function.

PoC by Snyk

require('minimist')('--_.constructor.constructor.prototype.foo bar'.split(' '));
console.log((function(){}).foo); // bar

Details

Prototype Pollution is a vulnerability affecting JavaScript. Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects. JavaScript allows all Object attributes to be altered, including their magical attributes such as __proto__, constructor and prototype. An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values. Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

  • Unsafe Object recursive merge

  • Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Type Origin Short description
Denial of service (DoS) Client This is the most likely attack.
DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf).
The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object. In this case, the code fails and is likely to cause a denial of service.
For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail.
Remote Code Execution Client Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
For example: eval(someobject.someattr). In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code.
Property Injection Client The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for someuser.isAdmin, then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true, they can then achieve admin privileges.

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

  • Application server

  • Web server

  • Web browser

How to prevent

  1. Freeze the prototype— use Object.freeze (Object.prototype).

  2. Require schema validation of JSON input.

  3. Avoid using unsafe recursive merge functions.

  4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

  5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade minimist to version 0.2.4, 1.2.6 or higher.

References

Prototype Pollution vulnerability report

low severity

Information Exposure

  • Vulnerable module: follow-redirects
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › github@12.1.0 › follow-redirects@1.2.6
    Remediation: Upgrade to next@5.0.0.
  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › glob-promise@3.2.0 › semantic-release@8.2.3 › @semantic-release/condition-travis@6.2.1 › github@12.1.0 › follow-redirects@1.2.6

Overview

Affected versions of this package are vulnerable to Information Exposure due a leakage of the Authorization header from the same hostname during HTTPS to HTTP redirection. An attacker who can listen in on the wire (or perform a MITM attack) will be able to receive the Authorization header due to the usage of the insecure HTTP protocol which does not verify the hostname the request is sending to.

Remediation

Upgrade follow-redirects to version 1.14.8 or higher.

References

Information Exposure vulnerability report

low severity

Cross-site Scripting

  • Vulnerable module: send
  • Introduced through: next@4.2.3

Detailed paths

  • Introduced through: zeit-deployments@pranaygp/zeit-deployments#9ab566bd78bef3d48d7549194bbfa2cdd145865f › next@4.2.3 › send@0.16.1
    Remediation: Upgrade to next@8.0.0.

Overview

send is a Better streaming static file server with Range and conditional-GET support

Affected versions of this package are vulnerable to Cross-site Scripting due to improper user input sanitization passed to the SendStream.redirect() function, which executes untrusted code. An attacker can execute arbitrary code by manipulating the input parameters to this method.

Note:

Exploiting this vulnerability requires the following:

  1. The attacker needs to control the input to response.redirect()

  2. Express MUST NOT redirect before the template appears

  3. The browser MUST NOT complete redirection before

  4. The user MUST click on the link in the template

Details

A cross-site scripting attack occurs when the attacker tricks a legitimate web-based application or site to accept a request as originating from a trusted source.

This is done by escaping the context of the web application; the web application then delivers that data to its users along with other trusted dynamic content, without validating it. The browser unknowingly executes malicious script on the client side (through client-side languages; usually JavaScript or HTML) in order to perform actions that are otherwise typically blocked by the browser’s Same Origin Policy.

Injecting malicious code is the most prevalent manner by which XSS is exploited; for this reason, escaping characters in order to prevent this manipulation is the top method for securing code against this vulnerability.

Escaping means that the application is coded to mark key characters, and particularly key characters included in user input, to prevent those characters from being interpreted in a dangerous context. For example, in HTML, < can be coded as &lt; and > can be coded as &gt; in order to be interpreted and displayed as themselves in text, while within the code itself, they are used for HTML tags. If malicious content is injected into an application that escapes special characters and that malicious content uses < and > as HTML tags, those characters are nonetheless not interpreted as HTML tags by the browser if they’ve been correctly escaped in the application code and in this way the attempted attack is diverted.

The most prominent use of XSS is to steal cookies (source: OWASP HttpOnly) and hijack user sessions, but XSS exploits have been used to expose sensitive information, enable access to privileged services and functionality and deliver malware.

Types of attacks

There are a few methods by which XSS can be manipulated:

Type Origin Description
Stored Server The malicious code is inserted in the application (usually as a link) by the attacker. The code is activated every time a user clicks the link.
Reflected Server The attacker delivers a malicious link externally from the vulnerable web site application to a user. When clicked, malicious code is sent to the vulnerable web site, which reflects the attack back to the user’s browser.
DOM-based Client The attacker forces the user’s browser to render a malicious page. The data in the page itself delivers the cross-site scripting data.
Mutated The attacker injects code that appears safe, but is then rewritten and modified by the browser, while parsing the markup. An example is rebalancing unclosed quotation marks or even adding quotation marks to unquoted parameters.

Affected environments

The following environments are susceptible to an XSS attack:

  • Web servers
  • Application servers
  • Web application environments

How to prevent

This section describes the top best practices designed to specifically protect your code:

  • Sanitize data input in an HTTP request before reflecting it back, ensuring all data is validated, filtered or escaped before echoing anything back to the user, such as the values of query parameters during searches.
  • Convert special characters such as ?, &, /, <, > and spaces to their respective HTML or URL encoded equivalents.
  • Give users the option to disable client-side scripts.
  • Redirect invalid requests.
  • Detect simultaneous logins, including those from two separate IP addresses, and invalidate those sessions.
  • Use and enforce a Content Security Policy (source: Wikipedia) to disable any features that might be manipulated for an XSS attack.
  • Read the documentation for any of the libraries referenced in your code to understand which elements allow for embedded HTML.

Remediation

Upgrade send to version 0.19.0, 1.1.0 or higher.

References

Cross-site Scripting vulnerability report