Shescape is a simple shell escape package for JavaScript. Affected versions were found to have insufficient escaping of white space when interpolating output. This issue only impacts users that use the `escape` or `escapeAll` functions with the `interpolation` option set to `true`. The result is that if an attacker is able to include whitespace in their input they can: 1. Invoke shell-specific behaviour through shell-specific special characters inserted directly after whitespace. 2. Invoke shell-specific behaviour through shell-specific special characters inserted or appearing after line terminating characters. 3. Invoke arbitrary commands by inserting a line feed character. 4. Invoke arbitrary commands by inserting a carriage return character. Behaviour number 1 has been patched in [v1.5.7] which you can upgrade to now. No further changes are required. Behaviour number 2, 3, and 4 have been patched in [v1.5.8] which you can upgrade to now. No further changes are required. The best workaround is to avoid having to use the `interpolation: true` option - in most cases using an alternative is possible, see [the recipes](https://github.com/ericcornelissen/shescape#recipes) for recommendations. Alternatively, users may strip all whitespace from user input. Note that this is error prone, for example: for PowerShell this requires stripping `'\u0085'` which is not included in JavaScript's definition of `\s` for Regular Expressions.
The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
Link | Tags |
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https://github.com/ericcornelissen/shescape/security/advisories/GHSA-44vr-rwwj-p88h | third party advisory exploit |
https://github.com/ericcornelissen/shescape/pull/322 | third party advisory patch |
https://github.com/ericcornelissen/shescape/pull/324 | third party advisory patch |
https://github.com/ericcornelissen/shescape/releases/tag/v1.5.7 | third party advisory release notes |
https://github.com/ericcornelissen/shescape/releases/tag/v1.5.8 | third party advisory release notes |