pypi · Malicious package advisory
Malwaresemvver
MAL-2026-18104
Malicious code in semvver (PyPI)
Details
--- _-= Per source details. Do not edit below this line.=-_ ## 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. --- 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.