Arbitrary File Creation/Overwrite due to insufficient absolute path sanitization
CVE-2021-32804
Key Information:
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What is CVE-2021-32804?
The npm package "tar" (aka node-tar) before versions 6.1.1, 5.0.6, 4.4.14, and 3.3.2 has a arbitrary File Creation/Overwrite vulnerability 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 /home/user/.bashrc would turn into home/user/.bashrc. This logic was insufficient when file paths contained repeated path roots such as ////home/user/.bashrc. node-tar would only strip 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) would still resolve to an absolute path, thus allowing arbitrary file creation and overwrite. This issue was addressed in releases 3.2.2, 4.4.14, 5.0.6 and 6.1.1. Users may work around this vulnerability without upgrading by creating a custom onentry method which sanitizes the entry.path or a filter method which removes entries with absolute paths. See referenced GitHub Advisory for details. Be aware of CVE-2021-32803 which fixes a similar bug in later versions of tar.
Affected Version(s)
node-tar < 3.2.2 < 3.2.2
node-tar >= 4.0.0, < 4.4.14 < 4.0.0, 4.4.14
node-tar >= 5.0.0, < 5.0.6 < 5.0.0, 5.0.6
Exploit Proof of Concept (PoC)
PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.
References
EPSS Score
84% chance of being exploited in the next 30 days.
CVSS V3.1
Timeline
- 🟡
Public PoC available
- 👾
Exploit known to exist
Vulnerability published
Vulnerability Reserved