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resolvedcritical

Malicious code in yzip (PyPI)

The yzip package on PyPI contained malicious code that downloads and executes multi-stage malware during archive-support class initialization. The malware exhibits obfuscation and infosteal capabilities, tracked as campaign 2025-11-uzip.

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Disclosed
Last updated
Blast radius
All users who installed the malicious yzip package from PyPI
Ecosystems
PyPI
Attack vectors
Compromised package
Threat actor
2025 11 Uzip
Affected entities
  • yzipPyPI package containing malicious code

The yzip package published on PyPI contained embedded malicious code designed to execute during the initialization of the archive-support class. Upon installation and import, the package would download and execute a remote executable payload, representing a multi-stage malware attack.

The malicious code included obfuscation techniques and was identified as part of campaign 2025-11-uzip. Analysis indicates clear malicious intent consistent with infostealer functionality, suggesting the attack aimed to compromise user systems and exfiltrate sensitive data.

The incident was identified and documented by the OpenSSF's malicious-packages repository (MAL-2025-192468), which tracks confirmed malicious packages across package ecosystems. The package has been removed from PyPI following disclosure.

Indicators of compromise

Packages
  • yzip

Remediation

  • Immediately uninstall yzip from all systems where it was installed
  • Scan affected systems for signs of compromise or malware execution
  • Review system logs and network traffic for indicators of the downloaded malware payload
  • Change credentials and review account activity on systems that may have been compromised
  • Monitor for data exfiltration or unauthorized access following the installation period

Sources

  1. GitHub Advisory GHSA-qw6w-66xx-g6w9 · GitHub Advisory Database

Cite this entry

"Malicious code in yzip (PyPI)." supplychainattack.org, Supply Chain Attack Incident Catalog. Disclosed July 21, 2026; last updated July 21, 2026. https://supplychainattack.org/incident/malicious-code-in-yzip-pypi-1i5q9u

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