Find, fix and prevent vulnerabilities in your code.
critical severity
- Vulnerable module: sanitize-html
- Introduced through: sanitize-html@1.11.4
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › sanitize-html@1.11.4Remediation: Upgrade to sanitize-html@2.0.0.
Overview
sanitize-html is a library that allows you to clean up user-submitted HTML, preserving whitelisted elements and whitelisted attributes on a per-element basis
Affected versions of this package are vulnerable to Arbitrary Code Execution. Tag transformations which turn an attribute value into a text node using transformTags
could be vulnerable to code execution.
Remediation
Upgrade sanitize-html
to version 2.0.0-beta or higher.
References
critical severity
- Vulnerable module: hawk
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › hawk@3.1.3
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › request@2.83.0 › hawk@6.0.2
Overview
hawk is a library for the HTTP Hawk Authentication Scheme.
Affected versions of this package are vulnerable to Authentication Bypass. The incoming (client supplied) hash of the payload is trusted by the server and not verified before the signature is calculated.
A malicious actor in the middle can alter the payload and the server side will not identify the modification occurred because it simply uses the client provided value instead of verify the hash provided against the modified payload.
According to the maintainers this issue is to be considered out of scope as "payload hash validation is optional and up to developer to implement".
Remediation
There is no fixed version for hawk
.
References
high severity
- Vulnerable module: nodemailer
- Introduced through: nodemailer@1.0.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › nodemailer@1.0.0Remediation: Upgrade to nodemailer@6.4.16.
Overview
nodemailer is an Easy as cake e-mail sending from your Node.js applications
Affected versions of this package are vulnerable to Command Injection. Use of crafted recipient email addresses may result in arbitrary command flag injection in sendmail transport for sending mails.
PoC
-bi@example.com (-bi Initialize the alias database.)
-d0.1a@example.com (The option -d0.1 prints the version of sendmail and the options it was compiled with.)
-Dfilename@example.com (Debug output ffile)
Remediation
Upgrade nodemailer
to version 6.4.16 or higher.
References
high severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@5.6.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Arbitrary File Write. node-tar
aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary stat calls to determine whether a given path is a directory, paths are cached when directories are created.
This logic was insufficient when extracting tar
files that contained both a directory and a symlink with the same name as the directory, where the symlink and directory names in the archive entry used backslashes as a path separator on posix systems. The cache checking logic used both \
and /
characters as path separators. However, \
is a valid filename character on posix systems.
By first creating a directory, and then replacing that directory with a symlink, it is possible to bypass node-tar
symlink checks on directories, essentially allowing an untrusted tar
file to symlink into an arbitrary location. This can lead to extracting arbitrary files into that location, thus allowing arbitrary file creation and overwrite.
Additionally, a similar confusion could arise on case-insensitive filesystems. If a tar
archive contained a directory at FOO
, followed by a symbolic link named foo
, then on case-insensitive file systems, the creation of the symbolic link would remove the directory from the filesystem, but not from the internal directory cache, as it would not be treated as a cache hit. A subsequent file entry within the FOO
directory would then be placed in the target of the symbolic link, thinking that the directory had already been created.
Remediation
Upgrade tar
to version 6.1.7, 5.0.8, 4.4.16 or higher.
References
high severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@5.6.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Arbitrary File Write. node-tar
aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary stat calls to determine whether a given path is a directory, paths are cached when directories are created.
This logic is insufficient when extracting tar
files that contain two directories and a symlink with names containing unicode values that normalized to the same value. Additionally, on Windows systems, long path portions would resolve to the same file system entities as their 8.3 "short path" counterparts.
A specially crafted tar
archive can include directories with two forms of the path that resolve to the same file system entity, followed by a symbolic link with a name in the first form, lastly followed by a file using the second form. This leads to bypassing node-tar
symlink checks on directories, essentially allowing an untrusted tar
file to symlink into an arbitrary location and extracting arbitrary files into that location.
Remediation
Upgrade tar
to version 6.1.9, 5.0.10, 4.4.18 or higher.
References
high severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@5.6.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Arbitrary File Write. node-tar
aims to guarantee that any file whose location would be outside of the extraction target directory is not extracted. This is, in part, accomplished by sanitizing absolute paths of entries within the archive, skipping archive entries that contain ..
path portions, and resolving the sanitized paths against the extraction target directory.
This logic is insufficient on Windows systems when extracting tar
files that contain a path that is not an absolute path, but specify a drive letter different from the extraction target, such as C:some\path
. If the drive letter does not match the extraction target, for example D:\extraction\dir
, then the result of path.resolve(extractionDirectory, entryPath)
resolves against the current working directory on the C:
drive, rather than the extraction target directory.
Additionally, a ..
portion of the path can occur immediately after the drive letter, such as C:../foo
, and is not properly sanitized by the logic that checks for ..
within the normalized and split portions of the path.
Note: This only affects users of node-tar
on Windows systems.
Remediation
Upgrade tar
to version 6.1.9, 5.0.10, 4.4.18 or higher.
References
high severity
- Vulnerable module: kerberos
- Introduced through: mongodb@2.0.33
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › mongodb@2.0.33 › mongodb-core@1.1.32 › kerberos@0.0.24Remediation: Upgrade to mongodb@2.0.48.
Overview
Affected versions of this package are vulnerable to DLL Injection. An attacker can execute arbitrary code by creating a file with the same name in a folder that precedes the intended file in the DLL path search.
Remediation
Upgrade kerberos
to version 1.0.0 or higher.
References
high severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@5.6.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Arbitrary File Overwrite. This is due to insufficient symlink protection.
node-tar
aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary stat
calls to determine whether a given path is a directory, paths are cached when directories are created.
This logic is insufficient when extracting tar files that contain both a directory and a symlink with the same name as the directory. This order of operations results in the directory being created and added to the node-tar
directory cache. When a directory is present in the directory cache, subsequent calls to mkdir
for that directory are skipped.
However, this is also where node-tar
checks for symlinks occur. By first creating a directory, and then replacing that directory with a symlink, it is possible to bypass node-tar
symlink checks on directories, essentially allowing an untrusted tar file to symlink into an arbitrary location and subsequently extracting arbitrary files into that location.
Remediation
Upgrade tar
to version 3.2.3, 4.4.15, 5.0.7, 6.1.2 or higher.
References
high severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@5.6.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Arbitrary File Overwrite. This is due to insufficient absolute path sanitization.
node-tar
aims to prevent extraction of absolute file paths by turning absolute paths into relative paths when the preservePaths
flag is not set to true
. This is achieved by stripping the absolute path root from any absolute file paths contained in a tar file. For example, the path /home/user/.bashrc
would turn into home/user/.bashrc
.
This logic is insufficient when file paths contain repeated path roots such as ////home/user/.bashrc
. node-tar
only strips a single path root from such paths. When given an absolute file path with repeating path roots, the resulting path (e.g. ///home/user/.bashrc
) still resolves to an absolute path.
Remediation
Upgrade tar
to version 3.2.2, 4.4.14, 5.0.6, 6.1.1 or higher.
References
high severity
- Vulnerable module: ajv
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › har-validator@4.2.1 › ajv@4.11.8Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › request@2.83.0 › har-validator@5.0.3 › ajv@5.5.2Remediation: Upgrade to npm@5.10.0.
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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
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
high severity
- Vulnerable module: npm
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0Remediation: Upgrade to npm@6.13.4.
Overview
npm is a package manager for JavaScript.
Affected versions of this package are vulnerable to Arbitrary File Overwrite. It fails to prevent existing globally-installed binaries to be overwritten by other package installations. For example, if a package was installed globally and created a serve
binary, any subsequent installs of packages that also create a serve
binary would overwrite the first binary. This only affects files in /usr/local/bin
.
For npm
, this behaviour is still allowed in local installations and also through install scripts. This vulnerability bypasses a user using the --ignore-scripts
install option.
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 npm
to version 6.13.4 or higher.
References
high severity
- Vulnerable module: npm
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0Remediation: Upgrade to npm@6.13.3.
Overview
npm is a package manager for JavaScript.
Affected versions of this package are vulnerable to Arbitrary File Write. It fails to prevent access to folders outside of the intended node_modules
folder through the bin field.
For npm
, a properly constructed entry in the package.json
bin field would allow a package publisher to modify and/or gain access to arbitrary files on a user’s system when the package is installed. This behaviour is possible through install scripts. This vulnerability bypasses a user using the --ignore-scripts install
option.
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 npm
to version 6.13.3 or higher.
References
high severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@5.6.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Arbitrary File Overwrite. Extracting tarballs containing a hard-link to a file that already exists in the system, and a file that matches the hard-link may overwrite system's files with the contents of the extracted file.
Remediation
Upgrade tar
to version 2.2.2, 4.4.2 or higher.
References
high severity
- Vulnerable module: ansi-regex
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › columnify@1.5.4 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@7.21.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npmlog@4.1.2 › gauge@2.7.4 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@7.20.1.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › update-notifier@2.2.0 › chalk@1.1.3 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › update-notifier@2.2.0 › chalk@1.1.3 › has-ansi@2.0.0 › ansi-regex@2.1.1
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npmlog@4.1.2 › gauge@2.7.4 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@7.20.1.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › yargs@8.0.2 › cliui@3.2.0 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@5.8.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › npmlog@4.1.2 › gauge@2.7.4 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-registry-client@8.5.1 › npmlog@4.1.2 › gauge@2.7.4 › strip-ansi@3.0.1 › ansi-regex@2.1.1
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › yargs@8.0.2 › cliui@3.2.0 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@5.8.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › npmlog@4.1.2 › gauge@2.7.4 › string-width@1.0.2 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-registry-client@8.5.1 › 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: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › yargs@8.0.2 › cliui@3.2.0 › wrap-ansi@2.1.0 › strip-ansi@3.0.1 › ansi-regex@2.1.1Remediation: Upgrade to npm@5.8.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › 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@2.1.1Remediation: Upgrade to npm@5.8.0.
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:
- CCC
- CC+C
- C+CC
- 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
high severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1
Overview
lodash is a modern JavaScript utility library delivering modularity, performance, & extras.
Affected versions of this package are vulnerable to Prototype Pollution through the zipObjectDeep
function due to improper user input sanitization in the baseZipObject
function.
PoC
lodash.zipobjectdeep:
const zipObjectDeep = require("lodash.zipobjectdeep");
let emptyObject = {};
console.log(`[+] Before prototype pollution : ${emptyObject.polluted}`);
//[+] Before prototype pollution : undefined
zipObjectDeep(["constructor.prototype.polluted"], [true]);
//we inject our malicious attributes in the vulnerable function
console.log(`[+] After prototype pollution : ${emptyObject.polluted}`);
//[+] After prototype pollution : true
lodash:
const test = require("lodash");
let emptyObject = {};
console.log(`[+] Before prototype pollution : ${emptyObject.polluted}`);
//[+] Before prototype pollution : undefined
test.zipObjectDeep(["constructor.prototype.polluted"], [true]);
//we inject our malicious attributes in the vulnerable function
console.log(`[+] After prototype pollution : ${emptyObject.polluted}`);
//[+] After prototype pollution : 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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade lodash
to version 4.17.17 or higher.
References
high severity
- Vulnerable module: mongodb
- Introduced through: mongodb@2.0.33
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › mongodb@2.0.33Remediation: Upgrade to mongodb@3.1.13.
Overview
mongodb is an official MongoDB driver for Node.js.
Affected versions of this package are vulnerable to Denial of Service (DoS). The package fails to properly catch an exception when a collection name is invalid and the DB does not exist, crashing the application.
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:
- CCC
- CC+C
- C+CC
- 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 mongodb
to version 3.1.13 or higher.
References
high severity
- Vulnerable module: semver
- Introduced through: npm@5.5.0 and semver@4.3.3
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › semver@5.3.0Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › semver@5.4.1Remediation: Upgrade to npm@5.7.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › semver@4.3.3Remediation: Upgrade to semver@5.7.2.
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:
- CCC
- CC+C
- C+CC
- 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
high severity
- Vulnerable module: ssri
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-registry-client@8.5.1 › ssri@5.3.0
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › ssri@5.3.0Remediation: Upgrade to npm@5.7.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › ssri@5.3.0Remediation: Upgrade to npm@6.0.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › cacache@10.0.4 › ssri@5.3.0Remediation: Upgrade to npm@5.7.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › cacache@10.0.4 › ssri@5.3.0Remediation: Upgrade to npm@6.0.0.
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:
- CCC
- CC+C
- C+CC
- 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
high severity
- Vulnerable module: hawk
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › hawk@3.1.3Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › request@2.83.0 › hawk@6.0.2Remediation: Upgrade to npm@5.10.0.
Overview
hawk is a library for the HTTP Hawk Authentication Scheme.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) in header parsing where each added character in the attacker's input increases the computation time exponentially.
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:
- CCC
- CC+C
- C+CC
- 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 hawk
to version 9.0.1 or higher.
References
high severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1
Overview
lodash is a modern JavaScript utility library delivering modularity, performance, & extras.
Affected versions of this package are vulnerable to Prototype Pollution. The function defaultsDeep
could be tricked into adding or modifying properties of Object.prototype
using a constructor
payload.
PoC by Snyk
const mergeFn = require('lodash').defaultsDeep;
const payload = '{"constructor": {"prototype": {"a0": true}}}'
function check() {
mergeFn({}, JSON.parse(payload));
if (({})[`a0`] === true) {
console.log(`Vulnerable to Prototype Pollution via ${payload}`);
}
}
check();
For more information, check out our blog post
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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade lodash
to version 4.17.12 or higher.
References
high severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1
Overview
lodash is a modern JavaScript utility library delivering modularity, performance, & extras.
Affected versions of this package are vulnerable to Prototype Pollution via the set
and setwith
functions due to improper user input sanitization.
PoC
lod = require('lodash')
lod.set({}, "__proto__[test2]", "456")
console.log(Object.prototype)
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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade lodash
to version 4.17.17 or higher.
References
high severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1
Overview
lodash is a modern JavaScript utility library delivering modularity, performance, & extras.
Affected versions of this package are vulnerable to Prototype Pollution. The functions merge
, mergeWith
, and defaultsDeep
could be tricked into adding or modifying properties of Object.prototype
. This is due to an incomplete fix to CVE-2018-3721
.
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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade lodash
to version 4.17.11 or higher.
References
high severity
- Vulnerable module: node.extend
- Introduced through: node.extend@1.1.3
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › node.extend@1.1.3Remediation: Upgrade to node.extend@1.1.7.
Overview
node.extend is a port of jQuery.extend that actually works on node.js.
Affected versions of this package are vulnerable to Prototype Pollution. An attacker could inject arbitrary properties onto Object.prototype
.
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:
- CCC
- CC+C
- C+CC
- 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 node.extend
to version 1.1.7, 2.0.1 or higher.
References
high severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1
Overview
lodash is a modern JavaScript utility library delivering modularity, performance, & extras.
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
Upgrade lodash
to version 4.17.21 or higher.
References
medium severity
- Vulnerable module: ip
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › socks-proxy-agent@3.0.1 › socks@1.1.10 › ip@1.1.9
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › socks-proxy-agent@3.0.1 › socks@1.1.10 › ip@1.1.9
Overview
ip is a Node library.
Affected versions of this package are vulnerable to Server-Side Request Forgery (SSRF) via the isPublic
function, which identifies some private IP addresses as public addresses due to improper parsing of the input.
An attacker can manipulate a system that uses isLoopback()
, isPrivate()
and isPublic
functions to guard outgoing network requests to treat certain IP addresses as globally routable by supplying specially crafted IP addresses.
Note
This vulnerability derived from an incomplete fix for CVE-2023-42282
Remediation
There is no fixed version for ip
.
References
medium severity
- Vulnerable module: request
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-registry-client@8.5.1 › request@2.88.2
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › request@2.83.0
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
medium severity
- Vulnerable module: sanitize-html
- Introduced through: sanitize-html@1.11.4
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › sanitize-html@1.11.4Remediation: Upgrade to sanitize-html@2.3.1.
Overview
sanitize-html is a library that allows you to clean up user-submitted HTML, preserving whitelisted elements and whitelisted attributes on a per-element basis
Affected versions of this package are vulnerable to Access Restriction Bypass. Internationalized domain name (IDN) is not properly handled. This allows attackers to bypass hostname whitelist validation set by the allowedIframeHostnames
option.
Remediation
Upgrade sanitize-html
to version 2.3.1 or higher.
References
medium severity
- Vulnerable module: sanitize-html
- Introduced through: sanitize-html@1.11.4
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › sanitize-html@1.11.4Remediation: Upgrade to sanitize-html@2.3.2.
Overview
sanitize-html is a library that allows you to clean up user-submitted HTML, preserving whitelisted elements and whitelisted attributes on a per-element basis
Affected versions of this package are vulnerable to Validation Bypass. There is no proper validation of the hostnames set by the allowedIframeHostnames
option when the allowIframeRelativeUrls
is set to true
. This allows attackers to bypass the hostname whitelist for the iframe element.
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 <
; and >
can be coded as >
; 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 sanitize-html
to version 2.3.2 or higher.
References
medium severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › tar@4.4.19Remediation: Upgrade to npm@7.0.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@7.0.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Uncontrolled Resource Consumption ('Resource Exhaustion') due to the lack of folders count validation during the folder creation process. An attacker who generates a large number of sub-folders can consume memory on the system running the software and even crash the client within few seconds of running it using a path with too many sub-folders inside.
Remediation
Upgrade tar
to version 6.2.1 or higher.
References
medium severity
- Vulnerable module: tough-cookie
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › request@2.83.0 › tough-cookie@2.3.4
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › tough-cookie@2.3.4
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-registry-client@8.5.1 › 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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
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
medium severity
- Vulnerable module: hoek
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › hawk@3.1.3 › hoek@2.16.3Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › hawk@3.1.3 › boom@2.10.1 › hoek@2.16.3Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › hawk@3.1.3 › sntp@1.0.9 › hoek@2.16.3Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › request@2.81.0 › hawk@3.1.3 › cryptiles@2.0.5 › boom@2.10.1 › hoek@2.16.3Remediation: Upgrade to npm@5.6.0.
Overview
hoek is an 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);
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:
- CCC
- CC+C
- C+CC
- 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 hoek
to version 4.2.1, 5.0.3 or higher.
References
medium severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1Remediation: Open PR to patch lodash@3.10.1.
Overview
lodash is a modern 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);
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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
For more information on this vulnerability type:
Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018
Remediation
Upgrade lodash
to version 4.17.5 or higher.
References
medium severity
- Vulnerable module: nodemailer
- Introduced through: nodemailer@1.0.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › nodemailer@1.0.0Remediation: Upgrade to nodemailer@6.6.1.
Overview
nodemailer is an Easy as cake e-mail sending from your Node.js applications
Affected versions of this package are vulnerable to HTTP Header Injection if unsanitized user input that may contain newlines and carriage returns is passed into an address object.
PoC:
const userEmail = 'foo@bar.comrnSubject: foobar'; // imagine this comes from e.g. HTTP request params or is otherwise user-controllable
await transporter.sendMail({
from: '...',
to: '...',
replyTo: {
name: 'Customer',
address: userEmail,
},
subject: 'My Subject',
text: message,
});
Remediation
Upgrade nodemailer
to version 6.6.1 or higher.
References
medium severity
- Vulnerable module: inflight
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › glob@7.1.7 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cacache@9.2.9 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › init-package-json@1.10.3 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › read-package-json@2.0.13 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › rimraf@2.6.3 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › move-concurrently@1.0.1 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cacache@9.2.9 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › fs-vacuum@1.2.10 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › init-package-json@1.10.3 › read-package-json@2.1.2 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › read-installed@4.0.3 › read-package-json@2.1.2 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › read-package-tree@5.1.6 › read-package-json@2.1.2 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › cacache@9.3.0 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › move-concurrently@1.0.1 › copy-concurrently@1.0.5 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cacache@9.2.9 › move-concurrently@1.0.1 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › fstream@1.0.12 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › cacache@9.3.0 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › cacache@10.0.4 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › cacache@10.0.4 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cacache@9.2.9 › move-concurrently@1.0.1 › copy-concurrently@1.0.5 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › cacache@9.3.0 › move-concurrently@1.0.1 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2 › fstream@1.0.12 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › cacache@10.0.4 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › cacache@10.0.4 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › cacache@9.3.0 › move-concurrently@1.0.1 › copy-concurrently@1.0.5 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › cacache@10.0.4 › move-concurrently@1.0.1 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › cacache@10.0.4 › move-concurrently@1.0.1 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › cacache@10.0.4 › move-concurrently@1.0.1 › copy-concurrently@1.0.5 › rimraf@2.7.1 › glob@7.2.3 › inflight@1.0.6
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › cacache@10.0.4 › move-concurrently@1.0.1 › copy-concurrently@1.0.5 › rimraf@2.7.1 › glob@7.2.3 › 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
- Vulnerable module: yargs-parser
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › yargs@8.0.2 › yargs-parser@7.0.0Remediation: Upgrade to npm@5.8.0.
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:
- It could be used for privilege escalation.
- 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 mergeProperty 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
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
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
medium severity
- Vulnerable module: got
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › update-notifier@2.2.0 › latest-version@3.1.0 › package-json@4.0.1 › got@6.7.1Remediation: Upgrade to npm@7.0.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › update-notifier@2.5.0 › latest-version@3.1.0 › package-json@4.0.1 › got@6.7.1
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
medium severity
- Vulnerable module: hosted-git-info
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › hosted-git-info@2.5.0Remediation: Upgrade to npm@5.8.0.
Overview
hosted-git-info is a Provides metadata and conversions from repository urls for Github, Bitbucket and Gitlab
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via regular expression shortcutMatch
in the fromUrl
function in index.js. The affected regular expression exhibits polynomial worst-case time complexity.
PoC by Yeting Li
var hostedGitInfo = require("hosted-git-info")
function build_attack(n) {
var ret = "a:"
for (var i = 0; i < n; i++) {
ret += "a"
}
return ret + "!";
}
for(var i = 1; i <= 5000000; i++) {
if (i % 1000 == 0) {
var time = Date.now();
var attack_str = build_attack(i)
var parsedInfo = hostedGitInfo.fromUrl(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:
- CCC
- CC+C
- C+CC
- 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 hosted-git-info
to version 3.0.8, 2.8.9 or higher.
References
medium severity
- Vulnerable module: http-cache-semantics
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-profile@2.0.5 › make-fetch-happen@2.6.0 › http-cache-semantics@3.8.1Remediation: Upgrade to npm@6.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › make-fetch-happen@2.6.0 › http-cache-semantics@3.8.1Remediation: Upgrade to npm@7.21.0.
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
Steps to reproduce:
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:
- CCC
- CC+C
- C+CC
- 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
medium severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1
Overview
lodash is a modern JavaScript utility library delivering modularity, performance, & extras.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the toNumber
, trim
and trimEnd
functions.
POC
var lo = require('lodash');
function build_blank (n) {
var ret = "1"
for (var i = 0; i < n; i++) {
ret += " "
}
return ret + "1";
}
var s = build_blank(50000)
var time0 = Date.now();
lo.trim(s)
var time_cost0 = Date.now() - time0;
console.log("time_cost0: " + time_cost0)
var time1 = Date.now();
lo.toNumber(s)
var time_cost1 = Date.now() - time1;
console.log("time_cost1: " + time_cost1)
var time2 = Date.now();
lo.trimEnd(s)
var time_cost2 = Date.now() - time2;
console.log("time_cost2: " + time_cost2)
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:
- CCC
- CC+C
- C+CC
- 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 lodash
to version 4.17.21 or higher.
References
medium severity
- Vulnerable module: nodemailer
- Introduced through: nodemailer@1.0.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › nodemailer@1.0.0Remediation: Upgrade to nodemailer@6.9.9.
Overview
nodemailer is an Easy as cake e-mail sending from your Node.js applications
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the attachDataUrls
parameter or when parsing attachments with an embedded file. An attacker can exploit this vulnerability by sending a specially crafted email that triggers inefficient regular expression evaluation, leading to excessive consumption of CPU resources.
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:
- CCC
- CC+C
- C+CC
- 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 nodemailer
to version 6.9.9 or higher.
References
medium severity
- Vulnerable module: npm
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0Remediation: Upgrade to npm@5.7.1.
Overview
npm is a package manager for JavaScript.
Affected versions of this package are vulnerable to Access Restriction Bypass. It might allow local users to bypass intended filesystem access restrictions due to ownerships of /etc
and /usr
directories are being changed unexpectedly, related to a "correctMkdir" issue.
Remediation
Upgrade npm
to version 5.7.1 or higher.
References
medium severity
- Vulnerable module: npm
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0Remediation: Upgrade to npm@6.14.6.
Overview
npm is a package manager for JavaScript.
Affected versions of this package are vulnerable to Insertion of Sensitive Information into Log File. The CLI supports URLs like <protocol>://[<user>[:<password>]@]<hostname>[:<port>][:][/]<path>
. The password value is not redacted and is printed to stdout and also to any generated log files.
Remediation
Upgrade npm
to version 6.14.6 or higher.
References
medium severity
- Vulnerable module: sanitize-html
- Introduced through: sanitize-html@1.11.4
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › sanitize-html@1.11.4Remediation: Upgrade to sanitize-html@2.12.1.
Overview
sanitize-html is a library that allows you to clean up user-submitted HTML, preserving whitelisted elements and whitelisted attributes on a per-element basis
Affected versions of this package are vulnerable to Information Exposure when used on the backend and with the style
attribute allowed, allowing enumeration of files in the system (including project dependencies). An attacker could exploit this vulnerability to gather details about the file system structure and dependencies of the targeted server.
PoC
// index.js
const sanitizeHtml = require('sanitize-html');
const file_exist = `<a style='background-image: url("/*# sourceMappingURL=./node_modules/sanitize-html/index.js */");'>@slonser_</a>`;
const file_notexist = `<a style='background-image: url("/*# sourceMappingURL=./node_modules/randomlibrary/index.js */");'>@slonser_</a>`;
const file_exist_clean = sanitizeHtml(file_exist, {
allowedAttributes: { ...sanitizeHtml.defaults.allowedAttributes, a: ['style'] },
})
const file_notexist_clean = sanitizeHtml(file_notexist, {
allowedAttributes: { ...sanitizeHtml.defaults.allowedAttributes, a: ['style'] },
})
console.log(file_exist_clean, "// valid file path on backend")
console.log(file_notexist_clean, "// invalid file path on backend")
Remediation
Upgrade sanitize-html
to version 2.12.1 or higher.
References
medium severity
- Vulnerable module: sanitize-html
- Introduced through: sanitize-html@1.11.4
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › sanitize-html@1.11.4Remediation: Upgrade to sanitize-html@2.7.1.
Overview
sanitize-html is a library that allows you to clean up user-submitted HTML, preserving whitelisted elements and whitelisted attributes on a per-element basis
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to insecure global regular expression replacement logic of HTML comment removal.
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:
- CCC
- CC+C
- C+CC
- 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 sanitize-html
to version 2.7.1 or higher.
References
medium severity
- Vulnerable module: ssri
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › ssri@4.1.6Remediation: Upgrade to npm@5.7.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cacache@9.2.9 › ssri@4.1.6Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › ssri@4.1.6Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › pacote@6.0.4 › cacache@9.3.0 › ssri@4.1.6Remediation: Upgrade to npm@5.6.0.
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) attacks. It used a regular expression (^([^-]+)-([A-Za-z0-9+/]+(?:=?=?))([?\\x21-\\x7E]*)$
) in order to match SRI hashes. This can cause an impact of about 10 seconds matching time for data 50k characters long.
Disclosure Timeline
- Feb 14th, 2018 - Initial Disclosure to package owner
- Feb 14th, 2018 - Initial Response from package owner
- Feb 14th, 2018 - Fix issued
- Feb 15th, 2018 - Vulnerability published
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:
- CCC
- CC+C
- C+CC
- 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 5.2.2 or higher.
References
medium severity
- Vulnerable module: mem
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › libnpx@9.6.0 › yargs@8.0.2 › os-locale@2.1.0 › mem@1.1.0Remediation: Upgrade to npm@5.8.0.
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
medium severity
- Vulnerable module: chownr
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › chownr@1.0.1Remediation: Upgrade to npm@6.6.0.
Overview
chownr is a package that takes the same arguments as fs.chown()
Affected versions of this package are vulnerable to Time of Check Time of Use (TOCTOU). Affected versions of this package are vulnerable toTime of Check Time of Use (TOCTOU) attacks.
It does not dereference symbolic links and changes the owner of the link, which can trick it into descending into unintended trees if a non-symlink is replaced by a symlink at a critical moment:
fs.lstat(pathChild, function(er, stats) {
if (er)
return cb(er)
if (!stats.isSymbolicLink())
chownr(pathChild, uid, gid, then)
Remediation
Upgrade chownr
to version 1.1.0 or higher.
References
medium severity
- Vulnerable module: lodash
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › cli-table2@0.2.0 › lodash@3.10.1
Overview
lodash is a modern JavaScript utility library delivering modularity, performance, & extras.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). It parses dates using regex strings, which may cause a slowdown of 2 seconds per 50k characters.
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:
- CCC
- CC+C
- C+CC
- 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 lodash
to version 4.17.11 or higher.
References
medium severity
- Module: npm
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0
Artistic-2.0 license
medium severity
- Module: npm-lifecycle
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › npm-lifecycle@1.0.3
Artistic-2.0 license
low severity
- Vulnerable module: tar
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › node-gyp@3.6.3 › tar@2.2.2Remediation: Upgrade to npm@5.6.0.
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0 › tar@4.0.2Remediation: Upgrade to npm@5.6.0.
Overview
tar is a full-featured Tar for Node.js.
Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS). When stripping the trailing slash from files
arguments, the f.replace(/\/+$/, '')
performance of this function can exponentially degrade when f
contains many /
characters resulting in ReDoS.
This vulnerability is not likely to be exploitable as it requires that the untrusted input is being passed into the tar.extract()
or tar.list()
array of entries to parse/extract, which would be unusual.
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:
- CCC
- CC+C
- C+CC
- 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 tar
to version 6.1.4, 5.0.8, 4.4.16 or higher.
References
low severity
- Vulnerable module: npm
- Introduced through: npm@5.5.0
Detailed paths
-
Introduced through: pimpmycause-rebuild@womenhackfornonprofits/pimpmycause-rebuild#42c54a078ba74e388ca7c77cd3e67fc8a5c63ffc › npm@5.5.0Remediation: Upgrade to npm@6.13.3.
Overview
npm is a package manager for JavaScript.
Affected versions of this package are vulnerable to Unauthorized File Access. It is possible for packages to create symlinks to files outside of thenode_modules
folder through the bin
field upon installation.
For npm
, a properly constructed entry in the package.json
bin field would allow a package publisher to create a symlink pointing to arbitrary files on a user’s system when the package is installed. This behaviour is possible through install scripts. This vulnerability bypasses a user using the --ignore-scripts
install option.
Remediation
Upgrade npm
to version 6.13.3 or higher.