{"id":"MAL-2026-17782","summary":"Malicious code in crypto-tax-export (RubyGems)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (d2481974cbcc361b29455129afea878124dafde18097efca0a87235df57f3bea)\nThe gem's native-extension build script ext/crypto_tax_export/extconf.rb runs during `gem install`. Before executing its payload it performs sandbox/analysis-evasion checks (CI environment variables, ephemeral/generated hostnames and usernames, known analysis paths, system uptime under 30 minutes, and presence of developer-signal files such as ~/.ssh, ~/.gem/credentials, and ~/.gitconfig). When those checks indicate a real developer workstation, it double-forks a detached, stdio-closed daemon that sleeps a randomized 20-40 minutes and then executes `eval(Base64.decode64(...))` on an embedded payload that opens a /bin/sh reverse shell via TCPSocket to the hardcoded bare IP 45.138.12.177:8089 in a reconnect loop. The create_makefile call is a stub targeting an unrelated name (`bitcoin_rpc_lite_native`), the shipped lib/crypto_tax_export.rb contains only trivial VERSION/build_id/healthy? methods with no tax-export functionality, and the README is for a different package (`bitcoin-rpc-lite`), indicating the extension script is the gem's sole purpose and the advertised identity is cover.\n","modified":"2026-10-11T14:30:07.619574367Z","published":"2026-10-11T13:47:41Z","database_specific":{"malicious-packages-origins":[{"modified_time":"2026-10-11T13:47:41Z","sha256":"d2481974cbcc361b29455129afea878124dafde18097efca0a87235df57f3bea","source":"amazon-inspector","versions":["0.9.1"],"id":"IN-MAL-2026-021361","import_time":"2026-10-11T14:17:59.293128453Z"}]},"references":[{"type":"PACKAGE","url":"https://rubygems.org/gems/crypto-tax-export/versions/0.9.1"}],"affected":[{"package":{"name":"crypto-tax-export","ecosystem":"RubyGems","purl":"pkg:gem/crypto-tax-export"},"versions":["0.9.1"],"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":"ext/crypto_tax_export/extconf.rb","sha256":"10218e975f54a4f11fe3954e1b584a5f05054003bf5773c3c2b8cceaa74ba763","tlsh":"9751775acf8359e55aa1c0c045798012faa3ab0a50646875f3ee0868ff59b26c0f12fe"},{"tlsh":"b2c02b409c10f00783b09561bbc0019ba800c0cc9000c30b4874063cc0988518e65419","path":"README.md","sha256":"c11ea90465c14afe868c0d0028b54d69fbad390a73ddb7779e88becd2957d8f3"}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/crypto-tax-export/MAL-2026-17782.json"}}],"schema_version":"1.9.0","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"}]}