CVE-2022-25918: Regular Expression Denial of Service (ReDoS)
Impact
This impacts users that use shescape to escape arguments:
- for the Unix shell Bash, or any not-officially-supported Unix shell; - using the escape or escapeAll functions with the interpolation option set to true.
An attacker can cause polynomial backtracking in terms of the input string length due to a Regular Expression in shescape that is vulnerable to Regular Expression Denial of Service (ReDoS). Example:
javascript import as shescape from "shescape";
/ 1. Prerequisites / const options = { interpolation: true, // and shell: "/bin/bash", // or shell: "some-not-officially-supported-shell", // or shell: undefined, // Only if the system's default shell is bash or an unsupported shell. };
/ 2. Attack / let userInput = '{,'.repeat(150000); // polynomial backtracking
/ 3. Usage / shescape.escape(userInput, options); // or shescape.escapeAll([userInput], options);
Patches
This bug has been patched in v1.6.1 which you can upgrade to now. No further changes required.
Workarounds
Alternatively, a maximum length can be enforced on input strings to shescape to reduce the impact of the vulnerability. It is not recommended to try and detect vulnerable input strings, as the logic for this may end up being vulnerable to ReDoS itself.
References
- Shescape commit 552e8ea - Shescape Release v1.6.1
For more information
- Comment on commit 552e8ea - Open an issue at https://github.com/ericcornelissen/shescape/issues (New issue > Question > Get started)
Other sources
The package shescape from 1.5.10 and before 1.6.1 are vulnerable to Regular Expression Denial of Service (ReDoS) via the escape function in index.js, due to the usage of insecure regex in the escapeArgBash function.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the impact of CVE-2022-25918?
The vulnerability allows an attacker to cause polynomial backtracking, leading to Denial of Service (DoS).
Which versions of shescape are affected by CVE-2022-25918?
Versions 1.5.10 to 1.6.0 of shescape are vulnerable.
How can I fix CVE-2022-25918?
Upgrade to version 1.6.1 of shescape to fix the vulnerability.
Where can I find more information about CVE-2022-25918?
You can find more information about CVE-2022-25918 in the following references: [GitHub Advisory](https://github.com/ericcornelissen/shescape/security/advisories/GHSA-cr84-xvw4-qx3c), [NVD](https://nvd.nist.gov/vuln/detail/CVE-2022-25918), [GitHub Commit](https://github.com/ericcornelissen/shescape/commit/552e8eab56861720b1d4e5474fb65741643358f9).