Malicious code in xsltproc (PyPI)
The xsltproc package on PyPI contained malicious code that exfiltrates basic host information (IP address, username) upon installation or module import. The package overrides the install command in setup.py to execute the malicious payload during installation.
- Disclosed
- Last updated
- Blast radius
- Any user who installed the malicious xsltproc package from PyPI
- Ecosystems
- Attack vectors
- Affected entities
- xsltprocPyPI package
The xsltproc package published on PyPI was found to contain intentionally malicious code designed to exfiltrate basic system information from infected hosts. The malicious payload is executed during package installation by overriding the install command in setup.py, ensuring code execution occurs before the package is fully installed.\n\nThe exfiltrated data includes basic host information such as IP addresses and usernames. According to the OpenSSF malicious packages database, this package was classified as a low-harm pentest-style package with limited risk scope, though any system information disclosure poses a privacy and reconnaissance threat.\n\nThe incident was identified and documented by the OpenSSF malicious packages project (MAL-2025-191937), which tracks intentionally malicious packages published to public repositories.
Indicators of compromise
- Packages
- xsltproc
Remediation
- Immediately uninstall the xsltproc package if installed: pip uninstall xsltproc
- Review system logs and network traffic from the time of installation to identify any data exfiltration
- Change credentials (passwords, SSH keys, API tokens) on affected systems as a precaution
- Scan systems for any additional malicious artifacts or persistence mechanisms
- Monitor for unauthorized access or reconnaissance activity on affected hosts
- Use only verified, legitimate packages from trusted sources; verify package authenticity before installation
Sources
- GitHub Advisory GHSA-8339-c9j3-rqv3 · GitHub Advisory Database
Cite this entry
"Malicious code in xsltproc (PyPI)." supplychainattack.org, Supply Chain Attack Incident Catalog. Disclosed July 21, 2025; last updated July 21, 2026. https://supplychainattack.org/incident/malicious-code-in-xsltproc-pypi-1ricwp
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