{"id":"MAL-2026-18092","title":"Malicious code in test-workalendar-internal (PyPI)","summary":"Malicious code in test-workalendar-internal (PyPI)","severity":"critical","exploited":true,"vendor":"test-workalendar-internal","product":"test-workalendar-internal","ecosystem":"pip","affected":["test-workalendar-internal"],"published":"2026-10-20","updated":"2026-10-20","sourceUpdated":"2026-10-20T18:30:11.131291138Z","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/MAL-2026-18092","references":[{"url":"https://bad-packages.kam193.eu/pypi/package/test-workalendar-internal"},{"url":"https://pypi.org/project/test-workalendar-internal/0.0.3/"}],"tags":["osv","pip","malware"],"ingestedAt":"2026-10-21T11:54:42.738Z","slug":"MAL-2026-18092","body":"## Overview\n\n\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (06eccee3c04982c18f9f348949477e1540d3e63eab7ae66f5d851428d0308597)\ntest-workalendar-internal 0.0.3 ships a custom Hatchling build hook that runs during `pip install` (sdist/wheel build). The hook downloads two standalone binaries — ttyd from github.com/tsl0922/ttyd and cloudflared from github.com/cloudflare/cloudflared — to /tmp/ttyd and /tmp/cloudflared, chmods them executable, and spawns ttyd bound to 127.0.0.1:7681 serving an interactive `bash` shell protected only by a generated basic-auth user/password. It then launches `cloudflared tunnel --url http://127.0.0.1:7681`, parses the resulting `*.trycloudflare.com` URL from cloudflared's stdout, and POSTs a JSON payload containing the tunnel URL, username, and password to the hardcoded collector https://webhook.site/f03cbdbe-704b-4932-a0a7-847d749c19b6. The combined effect is a fully automatic install-time remote shell on the installer's host: a remote party receives the public tunnel URL and basic-auth credentials and can interact with bash on the installer's machine. The package's declared purpose (a weekday/calendar helper) is unrelated to web terminals or tunnels.\n\n## Source: kam193 (9f36e976d0fcf254def6da62e0090bfb2dbdf76176ed316655574408c25cb9a0)\nDuring build, the package creates a web-sharable terminal session and exposes it via a Cloudflare tunnel to the attacker.\n\n\n---\n\nCategory: MALICIOUS - The campaign has clearly malicious intent, like infostealers.\n\n\nCampaign: 2026-10-test-workalendar-internal\n\n\nReasons (based on the campaign):\n\n\n - backdoor\n\n\n - The package overrides the install command in setup.py to execute malicious code during installation.\n\n\n## Affected packages\n\n- `test-workalendar-internal`\n\n## Remediation\n\nRefer to the advisory for the patched release.","depth":"abyssal","depthScore":70,"depthScoreParts":{"impact":52.3,"likelihood":0,"exploitation":18,"ransomware":0},"changes":[]}