bahmutov/next-update

Tests if module's dependencies can be updated to the newer version without breaking the tests.
Vulnerabilities 6 via 15 paths
Dependencies 284
Source GitHub
Commit 230d136b

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high severity

Uninitialized Memory Exposure

  • Vulnerable module: https-proxy-agent
  • Introduced through: changed-log@0.11.0

Detailed paths

  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 changed-log@0.11.0 github@2.4.0 https-proxy-agent@1.0.0

Overview

https-proxy-agent provides an http.Agent implementation that connects to a specified HTTP or HTTPS proxy server, and can be used with the built-in https module.

Affected versions of this package are vulnerable to Uninitialized Memory Exposure and Denial of Service (DoS) attacks due to passing unsanitized options to Buffer(arg).

Uninitialized memory Exposre PoC by ChALKer

// listen with: nc -l -p 8080
        
        var url = require('url');
        var https = require('https');
        var HttpsProxyAgent = require('https-proxy-agent');
        
        var proxy = {
          protocol: 'http:',
          host: "127.0.0.1",
          port: 8080
        };
        
        proxy.auth = 500; // a number as 'auth'
        var opts = url.parse('https://example.com/');
        var agent = new HttpsProxyAgent(proxy);
        opts.agent = agent;
        https.get(opts);
        

Details

The Buffer class on Node.js is a mutable array of binary data, and can be initialized with a string, array or number.

const buf1 = new Buffer([1,2,3]);
        // creates a buffer containing [01, 02, 03]
        const buf2 = new Buffer('test');
        // creates a buffer containing ASCII bytes [74, 65, 73, 74]
        const buf3 = new Buffer(10);
        // creates a buffer of length 10
        

The first two variants simply create a binary representation of the value it received. The last one, however, pre-allocates a buffer of the specified size, making it a useful buffer, especially when reading data from a stream. When using the number constructor of Buffer, it will allocate the memory, but will not fill it with zeros. Instead, the allocated buffer will hold whatever was in memory at the time. If the buffer is not zeroed by using buf.fill(0), it may leak sensitive information like keys, source code, and system info.

Remediation

Upgrade https-proxy-agent to version 2.2.0 or higher. Note This is vulnerable only for Node <=4

References

medium severity

Uninitialized Memory Exposure

  • Vulnerable module: tunnel-agent
  • Introduced through: request@2.74.0

Detailed paths

  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 request@2.74.0 tunnel-agent@0.4.3
    Remediation: Upgrade to request@2.81.0.

Overview

tunnel-agent is HTTP proxy tunneling agent. Affected versions of the package are vulnerable to Uninitialized Memory Exposure.

A possible memory disclosure vulnerability exists when a value of type number is used to set the proxy.auth option of a request request and results in a possible uninitialized memory exposures in the request body.

This is a result of unobstructed use of the Buffer constructor, whose insecure default constructor increases the odds of memory leakage.

Details

Constructing a Buffer class with integer N creates a Buffer of length N with raw (not "zero-ed") memory.

In the following example, the first call would allocate 100 bytes of memory, while the second example will allocate the memory needed for the string "100":

// uninitialized Buffer of length 100
        x = new Buffer(100);
        // initialized Buffer with value of '100'
        x = new Buffer('100');
        

tunnel-agent's request construction uses the default Buffer constructor as-is, making it easy to append uninitialized memory to an existing list. If the value of the buffer list is exposed to users, it may expose raw server side memory, potentially holding secrets, private data and code. This is a similar vulnerability to the infamous Heartbleed flaw in OpenSSL.

Proof of concept by ChALkeR

require('request')({
          method: 'GET',
          uri: 'http://www.example.com',
          tunnel: true,
          proxy:{
              protocol: 'http:',
              host:"127.0.0.1",
              port:8080,
              auth:80
          }
        });
        

You can read more about the insecure Buffer behavior on our blog.

Similar vulnerabilities were discovered in request, mongoose, ws and sequelize.

Remediation

Upgrade tunnel-agent to version 0.6.0 or higher. Note This is vulnerable only for Node <=4

References

low severity

Prototype Pollution

  • Vulnerable module: hoek
  • Introduced through: request@2.74.0

Detailed paths

  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 request@2.74.0 hawk@3.1.3 hoek@2.16.3
    Remediation: Upgrade to request@2.82.0.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 request@2.74.0 hawk@3.1.3 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to request@2.82.0.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 request@2.74.0 hawk@3.1.3 cryptiles@2.0.5 boom@2.10.1 hoek@2.16.3
    Remediation: Upgrade to request@2.82.0.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 request@2.74.0 hawk@3.1.3 sntp@1.0.9 hoek@2.16.3
    Remediation: Upgrade to request@2.82.0.

Overview

hoek is a Utility methods for the hapi ecosystem.

Affected versions of this package are vulnerable to Prototype Pollution. The utilities function allow modification of the Object prototype. If an attacker can control part of the structure passed to this function, they could add or modify an existing property.

PoC by Olivier Arteau (HoLyVieR)

var Hoek = require('hoek');
        var malicious_payload = '{"__proto__":{"oops":"It works !"}}';
        
        var a = {};
        console.log("Before : " + a.oops);
        Hoek.merge({}, JSON.parse(malicious_payload));
        console.log("After : " + a.oops);
        
        

Remediation

Upgrade hoek to versions 4.2.1, 5.0.3 or higher.

References

low severity

Prototype Pollution

  • Vulnerable module: lodash
  • Introduced through: deps-ok@1.1.0, lodash@3.10.1 and others

Detailed paths

  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 deps-ok@1.1.0 lodash@3.10.1
    Remediation: Upgrade to deps-ok@1.2.3.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 lodash@3.10.1
    Remediation: Upgrade to lodash@4.17.5.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 changed-log@0.11.0 lodash@3.10.1
    Remediation: Run snyk wizard to patch lodash@3.10.1.

Overview

lodash is a javaScript utility library delivering modularity, performance & extras.

Affected versions of this package are vulnerable to Prototype Pollution. The utilities function allow modification of the Object prototype. If an attacker can control part of the structure passed to this function, they could add or modify an existing property.

PoC by Olivier Arteau (HoLyVieR)

var _= require('lodash');
        var malicious_payload = '{"__proto__":{"oops":"It works !"}}';
        
        var a = {};
        console.log("Before : " + a.oops);
        _.merge({}, JSON.parse(malicious_payload));
        console.log("After : " + a.oops);
        

Remediation

Upgrade lodash to version 4.17.5 or higher.

References

low severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: debug
  • Introduced through: debug@2.2.0, changed-log@0.11.0 and others

Detailed paths

  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 debug@2.2.0
    Remediation: Upgrade to debug@2.6.9.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 changed-log@0.11.0 debug@2.2.0
    Remediation: Run snyk wizard to patch debug@2.2.0.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 npm-utils@1.7.1 debug@2.2.0
    Remediation: Upgrade to npm-utils@2.0.1.

Overview

debug is a JavaScript debugging utility modelled after Node.js core's debugging technique..

debug uses printf-style formatting. Affected versions of this package are vulnerable to Regular expression Denial of Service (ReDoS) attacks via the the %o formatter (Pretty-print an Object all on a single line). It used a regular expression (/\s*\n\s*/g) in order to strip whitespaces and replace newlines with spaces, in order to join the data into a single line. This can cause a very low impact of about 2 seconds matching time for data 50k characters long.

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 debug to version 2.6.9, 3.1.0 or higher.

References

low severity

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: ms
  • Introduced through: debug@2.2.0, changed-log@0.11.0 and others

Detailed paths

  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 debug@2.2.0 ms@0.7.1
    Remediation: Upgrade to debug@2.6.7.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 changed-log@0.11.0 debug@2.2.0 ms@0.7.1
    Remediation: Run snyk wizard to patch ms@0.7.1.
  • Introduced through: next-update@bahmutov/next-update#230d136b5c68dadb1fd5459619df8f7678d28429 npm-utils@1.7.1 debug@2.2.0 ms@0.7.1
    Remediation: Upgrade to npm-utils@2.0.0.

Overview

ms is a tiny millisecond conversion utility.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to an incomplete fix for previously reported vulnerability npm:ms:20151024. The fix limited the length of accepted input string to 10,000 characters, and turned to be insufficient making it possible to block the event loop for 0.3 seconds (on a typical laptop) with a specially crafted string passed to ms() function.

Proof of concept

ms = require('ms');
        ms('1'.repeat(9998) + 'Q') // Takes about ~0.3s
        

Note: Snyk's patch for this vulnerability limits input length to 100 characters. This new limit was deemed to be a breaking change by the author. Based on user feedback, we believe the risk of breakage is very low, while the value to your security is much greater, and therefore opted to still capture this change in a patch for earlier versions as well. Whenever patching security issues, we always suggest to run tests on your code to validate that nothing has been broken.

For more information on Regular Expression Denial of Service (ReDoS) attacks, go to our blog.

Disclosure Timeline

  • Feb 9th, 2017 - Reported the issue to package owner.
  • Feb 11th, 2017 - Issue acknowledged by package owner.
  • April 12th, 2017 - Fix PR opened by Snyk Security Team.
  • May 15th, 2017 - Vulnerability published.
  • May 16th, 2017 - Issue fixed and version 2.0.0 released.
  • May 21th, 2017 - Patches released for versions >=0.7.1, <=1.0.0.

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 ms to version 2.0.0 or higher.

References