Vulnerabilities

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high severity

Asymmetric Resource Consumption (Amplification)

  • Vulnerable module: ws
  • Introduced through: engine.io-client@5.2.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › engine.io-client@5.2.0 › ws@7.4.6
    Remediation: Upgrade to engine.io-client@6.6.6.

Overview

ws is a simple to use websocket client, server and console for node.js.

Affected versions of this package are vulnerable to Asymmetric Resource Consumption (Amplification) when handling a large number of very small fragments and data chunks. An attacker can cause excessive memory allocation and OOM by sending a high volume of tiny WebSocket frames

Workaround

This vulnerability can be mitigated by lowering the value of the maxPayload option.

PoC

import { WebSocket, WebSocketServer } from 'ws';

const wss = new WebSocketServer({ port: 0 }, function () {
  const data = Buffer.alloc(1);
  const options = { fin: false };
  const { port } = wss.address();
  const ws = new WebSocket(`ws://localhost:${port}`);

  ws.on('open', function () {
    (function send() {
      ws.send(data, options, function (err) {
        if (err) return;
        send();
      });
    })();
  });

  ws.on('error', console.error);
  ws.on('close', function (code, reason) {
    console.log(`client close - code: ${code} reason: ${reason.toString()}`);
  });
});

wss.on('connection', function (ws) {
  ws.on('error', console.error);
  ws.on('close', function (code, reason) {
    console.log(`server close - code: ${code} reason: ${reason.toString()}`);
  });
});

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 ws to version 5.2.5, 6.2.4, 7.5.11, 8.21.0 or higher.

References

high severity
new

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution via insufficient hardening of runtime option handling across multiple request-processing helpers (lib/helpers/resolveConfig.js, lib/helpers/toFormData.js, lib/adapters/fetch.js, and related files). An attacker can supply a manipulated configuration object that overrides internally owned fetch options (such as body, headers, method, signal) or bypasses the default formSerializer.maxDepth limit, leading to integrity violations in outgoing requests or a crash causing denial of service.

Note: This is only exploitable when the caller does not explicitly set formSerializer.maxDepth, allowing a prototype-level or caller-supplied value to override the expected default.

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

Remediation

Upgrade axios to version 0.34.0, 1.20.0 or higher.

References

high severity
new

Allocation of Resources Without Limits or Throttling

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via unsafe runtime option handling in the fetch and HTTP adapters, where user-supplied fetchOptions are merged into the resolved request options without sanitization. An attacker who can influence request configuration can trigger uncontrolled resource consumption, crashing the process.

Note: This is only exploitable when requests follow redirects (i.e., maxRedirects is not set to 0), unless application code manually follows the malicious redirect and re-enters axios.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

high severity
new

Improper Validation of Specified Quantity in Input

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Improper Validation of Specified Quantity in Input via unsafe runtime option handling in the fetch and HTTP adapters, where user-supplied fetchOptions are merged into the resolved request options without sanitization or allowlist enforcement. An attacker who can influence request configuration can supply option values that override Axios-owned fields (such as signal, method, headers, or body) or inject unexpected fetch option keys, causing the request pipeline to crash and producing a denial of service.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

high severity
new

Improper Validation of Specified Quantity in Input

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Improper Validation of Specified Quantity in Input via unsafe runtime option handling in the fetch and HTTP adapters, where user-supplied fetchOptions are merged into the resolved request options without sanitization or allowlist enforcement. An attacker who can influence request configuration can supply option values that override Axios-owned fields (such as signal, method, headers, or body) or inject unexpected fetch option keys, causing the request pipeline to crash and producing a denial of service.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

high severity
new

Regular Expression Denial of Service (ReDoS)

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via improper validation of runtime options in resolveConfig and related helpers, where an attacker-controlled or malformed configuration value can trigger a crash in the request processing pipeline. The hardening of option handling across fetch.js, http.js, dispatchRequest.js, and supporting helpers indicates that unsanitized option objects could be passed through to the underlying fetch or HTTP adapter in a way that causes an unhandled runtime error, crashing the process and denying service to other users.

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 axios to version 1.20.0 or higher.

References

high severity
new

Unintended Proxy or Intermediary ('Confused Deputy')

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Unintended Proxy or Intermediary ('Confused Deputy') via insufficient hardening of runtime option handling in the fetch and HTTP adapters (lib/adapters/fetch.js, lib/adapters/http.js, and related helpers). An authenticated attacker can supply malicious request options that are passed through without sanitization, allowing them to override Axios-controlled fetch properties such as body, headers, method, signal, duplex, and credentials, leading to a full compromise of request confidentiality and integrity.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

high severity

Denial of Service (DoS)

  • Vulnerable module: ws
  • Introduced through: engine.io-client@5.2.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › engine.io-client@5.2.0 › ws@7.4.6
    Remediation: Upgrade to engine.io-client@6.5.4.

Overview

ws is a simple to use websocket client, server and console for node.js.

Affected versions of this package are vulnerable to Denial of Service (DoS) when the number of received headers exceed the server.maxHeadersCount or request.maxHeadersCount threshold.

Workaround

This issue can be mitigating by following these steps:

  1. Reduce the maximum allowed length of the request headers using the --max-http-header-size=size and/or the maxHeaderSize options so that no more headers than the server.maxHeadersCount limit can be sent.

  2. Set server.maxHeadersCount to 0 so that no limit is applied.

PoC


const http = require('http');
const WebSocket = require('ws');

const server = http.createServer();

const wss = new WebSocket.Server({ server });

server.listen(function () {
  const chars = "!#$%&'*+-.0123456789abcdefghijklmnopqrstuvwxyz^_`|~".split('');
  const headers = {};
  let count = 0;

  for (let i = 0; i < chars.length; i++) {
    if (count === 2000) break;

    for (let j = 0; j < chars.length; j++) {
      const key = chars[i] + chars[j];
      headers[key] = 'x';

      if (++count === 2000) break;
    }
  }

  headers.Connection = 'Upgrade';
  headers.Upgrade = 'websocket';
  headers['Sec-WebSocket-Key'] = 'dGhlIHNhbXBsZSBub25jZQ==';
  headers['Sec-WebSocket-Version'] = '13';

  const request = http.request({
    headers: headers,
    host: '127.0.0.1',
    port: server.address().port
  });

  request.end();
});

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 ws to version 5.2.4, 6.2.3, 7.5.10, 8.17.1 or higher.

References

high severity
new

Server-side Request Forgery (SSRF)

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via unsafe merging of user-supplied fetchOptions into the resolved request options object in lib/adapters/fetch.js. An attacker who controls request configuration can supply a fetchOptions object with prototype-polluting keys (e.g. __proto__ or constructor), which are spread directly into the options passed to the Fetch API without sanitization, allowing pollution of Object.prototype and affecting downstream system-level behaviour. The fix replaces the spread with Object.assign(Object.create(null), fetchOptions) to strip inherited properties and enforces an allowlist of safe Fetch API keys.

Note: This is only exploitable when the attacker can influence the fetchOptions configuration passed to axios requests.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

high severity
new

Unintended Proxy or Intermediary ('Confused Deputy')

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Unintended Proxy or Intermediary ('Confused Deputy') via improper enforcement of maxRedirects: 0 in the fetch adapter, where user-supplied fetchOptions are merged into the resolved request options without defaulting the redirect field. When a caller sets maxRedirects: 0 to prevent redirects, the fetch adapter does not apply redirect: 'manual' unless the caller also explicitly sets fetchOptions.redirect, causing the underlying fetch runtime to silently follow a 302 redirect from the initial target and forward the request - including any credentials or sensitive headers - to the redirect destination, which may be attacker-controlled.

Note: This is only exploitable when requests are configured with maxRedirects: 0 but without fetchOptions.redirect: 'manual' or an equivalent runtime-specific redirect control.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

medium severity
new

Improper Input Validation

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Improper Input Validation via insufficient hardening of runtime option handling in the fetch and HTTP adapters, where user-supplied fetchOptions are merged into the resolved request options without sanitization. An attacker who can influence request configuration can inject or override internal Axios-owned options (such as body, headers, method, signal, credentials), leading to integrity impact on the downstream system receiving the request.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

medium severity
new

Improper Isolation or Compartmentalization

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Improper Isolation or Compartmentalization in lib/helpers/shouldBypassProxy.js, which matches NO_PROXY entries by exact host or IP and has no parsing for CIDR notation, so an entry such as 127.0.0.0/8 or 10.0.0.0/8 never matches and the request is routed through the configured proxy. An attacker able to observe or operate that proxy can read internal hostnames, request URLs, headers, and any credentials those requests carry, by receiving traffic the deployment intended to keep direct. This requires a Node.js deployment with HTTP_PROXY or HTTPS_PROXY set, at least one NO_PROXY entry written in CIDR form, and a proxy sitting outside the intended trust boundary, and exact host or IP entries in NO_PROXY are matched correctly.

Note: This is only exploitable when requests are configured with proxy: false.

Workaround

This vulnerability can be avoided by writing NO_PROXY entries for sensitive destinations as exact hosts or IP addresses rather than CIDR ranges.

Remediation

Upgrade axios to version 1.20.0 or higher.

References

medium severity
new

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution via unsafe merging of user-supplied fetchOptions in lib/adapters/fetch.js. When a caller passes a fetchOptions object, axios spreads it directly into the resolved request options without sanitizing prototype-inherited properties, allowing an attacker who controls request configuration to pollute Object.prototype and influence downstream system behavior such as request routing or security-sensitive option values.

Note: This is only exploitable when the attacker can influence the fetchOptions configuration object passed to axios requests.

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

Remediation

Upgrade axios to version 1.20.0 or higher.

References

medium severity
new

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution via insufficiently hardened runtime option handling in the fetch and HTTP adapters (lib/adapters/fetch.js, lib/adapters/http.js, and related helpers), where user-controlled or prototype-polluted properties on request configuration objects are merged into fetch/request options without sanitization. An attacker who can introduce a prototype-pollution gadget elsewhere in the application can inject arbitrary properties into the resolved fetch options, leading to integrity violations on outbound requests.

Note: This is only exploitable if an existing prototype-pollution path is present in the application.

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

Remediation

Upgrade axios to version 0.34.0, 1.20.0 or higher.

References

medium severity
new

Prototype Pollution

  • Vulnerable module: axios
  • Introduced through: axios@1.19.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › axios@1.19.0
    Remediation: Upgrade to axios@1.20.0.

Overview

axios is a promise-based HTTP client for the browser and Node.js.

Affected versions of this package are vulnerable to Prototype Pollution via insufficient hardening of runtime option handling in the fetch and HTTP adapters (lib/adapters/fetch.js, lib/adapters/http.js, and related helpers). An attacker who can influence request configuration options passed to axios can supply unsanitized values that bypass expected constraints, resulting in unintended modification of downstream system behavior (SI:H) such as request routing or proxy bypass, while leaving the client-side response unaffected (VC:N, VI:N, VA:N).

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

Remediation

Upgrade axios to version 1.20.0 or higher.

References

medium severity

Uncaught Exception

  • Vulnerable module: qs
  • Introduced through: qs@6.15.3 and body-parser@1.20.6

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › qs@6.15.3
    Remediation: Upgrade to qs@6.16.0.
  • Introduced through: snyk-broker@snyk/broker › body-parser@1.20.6 › qs@6.15.3
    Remediation: Upgrade to body-parser@1.20.8.

Overview

qs is a querystring parser that supports nesting and arrays, with a depth limit.

Affected versions of this package are vulnerable to Uncaught Exception in the isBuffer() function in lib/utils.js, which calls obj.constructor.isBuffer(obj) without checking that it is callable, reached from stringify() at lib/stringify.js:127. An attacker can throw an uncaught TypeError that fails each request with HTTP 500, and terminates the worker process when stringify() runs in an unguarded async context, by supplying a query string such as x[constructor][isBuffer]=y that sets constructor.isBuffer to a non-function value. This requires the application to call qs.parse() with plainObjects: true or allowPrototypes: true, which preserves the constructor own property, and to then pass the parsed result to qs.stringify().

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 qs to version 6.16.0 or higher.

References

medium severity
new

Improper Validation of Specified Quantity in Input

  • Vulnerable module: sprintf-js
  • Introduced through: global-agent@3.0.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › global-agent@3.0.0 › roarr@2.15.4 › sprintf-js@1.1.3

Overview

Affected versions of this package are vulnerable to Improper Validation of Specified Quantity in Input via unbounded precision specifiers passed without validation to the toFixed, toExponential, and toPrecision methods. An attacker who controls a format string can inject precision values exceeding ECMAScript limits, causing uncaught RangeError exceptions that abort the calling operation.

Remediation

There is no fixed version for sprintf-js.

References

medium severity

Allocation of Resources Without Limits or Throttling

  • Vulnerable module: qs
  • Introduced through: qs@6.15.3 and body-parser@1.20.6

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › qs@6.15.3
    Remediation: Upgrade to qs@6.16.0.
  • Introduced through: snyk-broker@snyk/broker › body-parser@1.20.6 › qs@6.15.3
    Remediation: Upgrade to body-parser@1.20.8.

Overview

qs is a querystring parser that supports nesting and arrays, with a depth limit.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the parseArrayValue() comma-parsing logic, which applies the arrayLimit and throwOnLimitExceeded checks only to flat values, so a bracket-key input such as a[]=1,2,3,4 is treated as non-flat and its comma-split inner array is wrapped after parsing without ever being length-checked. An attacker can exceed the configured array limit and force excessive memory allocation by supplying a query string or form body that uses the bracket-key comma form, for example a[]=1,2,3,.... This requires the application to parse untrusted input with the comma: true option enabled alongside a configured arrayLimit or throwOnLimitExceeded.

PoC


const qs = require('qs')
const options = { comma: true, arrayLimit: 3, throwOnLimitExceeded: true }

const result = qs.parse('a[]=1,2,3,4', options)
console.log(result.a[0].length) // 4; expected RangeError

const big = qs.parse('a[]=' + '1,'.repeat(1000000) + '1', { comma: true, arrayLimit: 20 })
console.log(big.a[0].length) // 1000001

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 qs to version 6.16.0 or higher.

References

medium severity

Missing Release of Resource after Effective Lifetime

  • Vulnerable module: inflight
  • Introduced through: bunyan@1.8.15

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › bunyan@1.8.15 › mv@2.1.1 › rimraf@2.4.5 › glob@6.0.4 › inflight@1.0.6

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

medium severity

LGPL-3.0 license

  • Module: openpgp
  • Introduced through: openpgp@6.3.0

Detailed paths

  • Introduced through: snyk-broker@snyk/broker › openpgp@6.3.0

LGPL-3.0 license