{"id":"MAL-2026-18599","summary":"Malicious code in w002yardprobe (RubyGems)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (721580f8eda44ad5ee7604f5ba0648e8830302f784e3e4a995e02ca7359c909e)\nThe gem ships a `.yardopts` file containing `--load./script.rb`, which causes YARD to execute `script.rb` whenever documentation is generated for the gem (locally via `yard doc`, in CI, or on doc-hosting services such as RubyDoc.info). `script.rb` collects host identifiers — `Socket.gethostname`, current working directory, UID, and `RUBY_VERSION` — and POSTs them via `Net::HTTP.post_form` to the hardcoded third-party collector `https://webhook.site/97fa3c6a-3fad-4d2d-8312-15dc37e41e66`. The same script also rewrites `lib/w002yardprobe.rb` in place (substituting a `MARKSLOT` token with a runtime stamp) and drops sentinel files `W002SCRIPT_RAN.txt` and `W002EGRESS_OK.txt` in the detected build directory (e.g. `/build`), indicating the gem is instrumented to probe a documentation-build sandbox. The package self-identifies as a probe; the exfiltration and build-environment mutation are the gem's purpose. The trigger is YARD doc generation rather than `gem install` or `require`, so the harm materializes against whichever host (developer workstation, CI runner, or doc-hosting pipeline) processes the gem's documentation.\n","modified":"2026-11-04T03:30:03.195537037Z","published":"2026-11-04T02:58:21Z","database_specific":{"malicious-packages-origins":[{"modified_time":"2026-11-04T02:58:29Z","sha256":"5252a1d5dd27d6e0edd3c1fc3936ff09d93b2fcc8e5544afc09fe7fb7d90bee5","source":"amazon-inspector","versions":["0.0.4"],"id":"IN-MAL-2026-022534","import_time":"2026-11-04T03:13:46.189246589Z"},{"id":"IN-MAL-2026-022533","import_time":"2026-11-04T03:13:46.098494137Z","modified_time":"2026-11-04T02:58:21Z","sha256":"721580f8eda44ad5ee7604f5ba0648e8830302f784e3e4a995e02ca7359c909e","source":"amazon-inspector","versions":["0.0.5"]}]},"references":[{"type":"PACKAGE","url":"https://rubygems.org/gems/w002yardprobe/versions/0.0.4"},{"type":"PACKAGE","url":"https://rubygems.org/gems/w002yardprobe/versions/0.0.5"}],"affected":[{"package":{"name":"w002yardprobe","ecosystem":"RubyGems","purl":"pkg:gem/w002yardprobe"},"versions":["0.0.4","0.0.5"],"database_specific":{"cwes":[{"description":"The product contains code that appears to be malicious in nature.","name":"Embedded Malicious Code","cweId":"CWE-506"},{"cweId":"CWE-506","description":"The product contains code that appears to be malicious in nature.","name":"Embedded Malicious Code"}],"indicators":{"package_integrity":[{"filename":"w002yardprobe-0.0.4.gem","hashes":{"sha256":"2c92205c8a1ecbffe953de63a4308e7de19bff714f6b01a67f1780bd38f39794"}}],"evidence_files":[{"sha256":"1a9aaf4ada6ff1225a0c9066bcc9ba27f91ce8eaf928fcfed5e32939e21a4f89","tlsh":"dc4142725cc14d7b67e0e4483e2c1550f762614fc70418703aad426a2f65d3ba2b5bfb","path":"script.rb"}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/w002yardprobe/MAL-2026-18599.json"}}],"schema_version":"1.9.2","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"}]}