Malicious code in yuzo (PyPI)
The yuzo package on PyPI contained malicious code implementing an infostealer (CStealer-based) designed to exfiltrate browser data and other sensitive information to a hardcoded Discord webhook. Multiple versions of the package were affected with varying implementations of the malware.
- Disclosed
- Last updated
- Blast radius
- All users who installed the malicious yuzo package versions
- Ecosystems
- Attack vectors
- Threat actor
- Affected entities
- yuzoPyPI package containing infostealer malware
The yuzo package published on PyPI contained embedded malicious code with clear intent to steal user information. The malware implements an infostealer capability, with newer versions based on CStealer, a known data exfiltration tool.\n\nThe malicious code was configured to exfiltrate stolen data to a hardcoded Discord webhook endpoint, enabling automated collection of sensitive information from affected systems. Different versions of the package contained variations of the infostealer payload.\n\nThe incident was identified and attributed to the 2025-09-suyo campaign by the OpenSSF's malicious-packages project. The malware specifically targets browser data and other sensitive user information for exfiltration.
Indicators of compromise
- Packages
- yuzo
Remediation
- Immediately uninstall the yuzo package from all systems
- Audit systems that installed yuzo for signs of compromise or data exfiltration
- Change passwords and sensitive credentials on affected systems
- Monitor for suspicious network connections to Discord webhooks or other C2 infrastructure
- Review browser history and check for unauthorized access to stored credentials or sensitive data
- Consider the yuzo package as untrusted and do not reinstall
Sources
- GitHub Advisory GHSA-38qh-vg5h-3j68 · GitHub Advisory Database
Cite this entry
"Malicious code in yuzo (PyPI)." supplychainattack.org, Supply Chain Attack Incident Catalog. Disclosed July 21, 2026; last updated July 21, 2026. https://supplychainattack.org/incident/malicious-code-in-yuzo-pypi-t867y0
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