VYPR

pypi · Malicious package advisory

Malware

semvver

MAL-2026-18104

Malicious code in semvver (PyPI)

Details


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## Source: amazon-inspector (bbc16b0ced0bad1a33b912dfdb29cbaef211f30974d942991257d4e6b60a8ece)
setup.py performs an install-time fetch-and-execute: it calls urllib.request.urlretrieve against https://c2-worker.crawlnet-claim.workers.dev/dl/pyupd, writes the response to a temporary path, and spawns it as a detached background process via subprocess.Popen with start_new_session=True. The fetch is unpinned and has no hash or signature verification, exceptions are swallowed, and the destination is a Cloudflare Workers subdomain unrelated to any PyPI publisher identity. The package has no other functionality — __init__.py is empty and the description is a generic 'utility helpers' string — so the install hook is the package's entire payload. The downloaded binary name 'pyupd' is a cover-story label; the behavior is a classic install-time dropper that grants whoever controls the Workers endpoint arbitrary code execution on the installer's host, running detached and persisting beyond the pip process.

## Source: kam193 (870775cad2a7f248b017394e8fbdb3470f6799de13d3ad278f1440b5b470c275)
During installation, package downloads and executes malware.


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Category: MALICIOUS - The campaign has clearly malicious intent, like infostealers.


Campaign: 2026-10-semvver


Reasons (based on the campaign):


 - Downloads and executes a remote executable.


 - malware


 - typosquatting

Compromised versions (1)

  • 1.0.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.