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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

• GitHub Commit
• GitHub PR
• Maintainer's Advisory

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

• GitHub Advisory
• GitHub Commit
• GitHub PR
• GitHub Release

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:

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

• GitHub Commit
• GitHub PR
• Maintainer's Advisory

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:

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

• GitHub Commit
• GitHub PR
• Maintainer's Advisory

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:

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

• GitHub Commit
• GitHub PR
• Maintainer's Advisory

Overview

brace-expansion is a Brace expansion as known from sh/bash

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the expand_ function, which implements a Bash quirk where a brace group followed by a comma set (e.g. {a},b}) causes the parser to rewrite the input string and restart the scan, absorbing one closing brace per pass. Because each pass re-reads the entire string and the string itself grows by approximately 25 characters per rewrite (due to the escClose sentinel), the work is quadratic in the number of trailing braces, allowing an attacker to block the event loop with a small input. An input of the form '{a}' + '}'.repeat(128000) + ',z}' takes approximately 27 seconds to process while producing only two results, and neither the existing max nor maxLength guards can prevent this because the cost is incurred during parsing before any result set is produced.

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.

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 brace-expansion to version 1.1.21, 2.1.7, 3.0.9, 5.0.12 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub Commit
• Maintainer's Advisory

Overview

Affected versions of this package are vulnerable to Incorrect Regular Expression in the escapeRegex function in index.js, which escapes ], \, /, (, ), *, +, ?, ., and $ but leaves ^, |, [, {, and } intact, and whose output is joined into the alternation that the RedirectableRequest constructor compiles into this._headerFilter. An attacker can receive a custom credential header that the application declared through sensitiveHeaders by drawing the request into a cross-origin redirect to a host they control, because a declared name holding ^, such as X-Api^Key, gains a mid-pattern start-of-string anchor and can never match, while one holding |, such as X-Token|Secret, splits into the separate alternatives X-Token and Secret, so the real header is forwarded and unrelated headers by those names are stripped instead. Only ^ and | are reachable in practice, since Node rejects [, {, and } in header names with ERR_INVALID_HTTP_TOKEN and declaring one of them instead throws a SyntaxError from the constructor, and the built-in Authorization, Proxy-Authorization, and Cookie entries contain no metacharacters, so the failure is confined to applications that declare their own names and silently lose the protection they configured.

Remediation

Upgrade follow-redirects to version 1.16.1 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Release

Overview

smol-toml is an A small, fast, and correct TOML parser/serializer

Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity via the parseKey function in src/struct.ts, which used the regular expression KEY_PART_RE (/^[a-zA-Z0-9-_]+[ \t]*$/) to validate bare key components. An attacker can supply a TOML document containing a long bare key with trailing characters that cause catastrophic backtracking in the regex engine, blocking the event loop and crashing the process.

Remediation

Upgrade smol-toml to version 1.9.0 or higher.

References

• GitHub Commit
• Maintainer's Advisory