{"id":"MAL-2026-18104","summary":"Malicious code in semvver (PyPI)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (bbc16b0ced0bad1a33b912dfdb29cbaef211f30974d942991257d4e6b60a8ece)\nsetup.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.\n\n## Source: kam193 (870775cad2a7f248b017394e8fbdb3470f6799de13d3ad278f1440b5b470c275)\nDuring installation, package downloads and executes malware.\n\n\n---\n\nCategory: MALICIOUS - The campaign has clearly malicious intent, like infostealers.\n\n\nCampaign: 2026-10-semvver\n\n\nReasons (based on the campaign):\n\n\n - Downloads and executes a remote executable.\n\n\n - malware\n\n\n - typosquatting\n","modified":"2026-10-20T19:30:07.604250075Z","published":"2026-10-20T18:20:39Z","database_specific":{"iocs":{"domains":["c2-worker.crawlnet-claim.workers.dev"],"urls":["https://c2-worker.crawlnet-claim.workers.dev/dl/pyupd"]},"malicious-packages-origins":[{"id":"IN-MAL-2026-021537","import_time":"2026-10-20T18:22:19.910972281Z","modified_time":"2026-10-20T18:20:39Z","sha256":"bbc16b0ced0bad1a33b912dfdb29cbaef211f30974d942991257d4e6b60a8ece","source":"amazon-inspector","versions":["1.0.0"]},{"modified_time":"2026-10-20T18:27:10.366642Z","sha256":"870775cad2a7f248b017394e8fbdb3470f6799de13d3ad278f1440b5b470c275","source":"kam193","versions":["1.0.0"],"id":"pypi/2026-10-semvver/semvver","import_time":"2026-10-20T19:15:26.421626699Z"}]},"references":[{"type":"PACKAGE","url":"https://pypi.org/project/semvver/1.0.0/"},{"type":"EVIDENCE","url":"https://www.virustotal.com/gui/file/e6d96b5500b232bea67f6f9046cfbc22d29a515c42d2af9523a15ebe8a7c4ab7/"},{"type":"WEB","url":"https://bad-packages.kam193.eu/pypi/package/semvver"}],"affected":[{"package":{"name":"semvver","ecosystem":"PyPI","purl":"pkg:pypi/semvver"},"versions":["1.0.0"],"database_specific":{"cwes":[{"description":"The product contains code that appears to be malicious in nature.","name":"Embedded Malicious Code","cweId":"CWE-506"}],"indicators":{"evidence_files":[{"path":"setup.py","sha256":"dcadfe8e0f4fcc578d613e8f9c0913edae241e61d39f2e5bac7425ab347148da","tlsh":"58f0c992c617673582c2d231ee3204632ffb9603e783d8f0369c93946fce87a8124a09"}],"package_integrity":[{"filename":"semvver-1.0.0.tar.gz","hashes":{"md5":"ac69532606a46f0ae5a7ba85362c6ee9","sha256":"7cc51e37ad6c8bc62d3352b6f3976a9da8e2e5f6f77132c29603aca68ec17e9e","blake2b_256":"e40c725d4c4070b703f310d3ede05bec3c8e48aaf700fab9c1df23e9c2ecc073"}}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/pypi/semvver/MAL-2026-18104.json"}}],"schema_version":"1.9.0","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"},{"name":"Kamil Mańkowski (kam193)","contact":["https://github.com/kam193","https://bad-packages.kam193.eu/"],"type":"REPORTER"}]}