{"id":"MAL-2026-18181","summary":"Malicious code in test-brotli-testmetest (npm)","details":"test-brotli-testmetest 1.0.0 ships a rebuild of the data-pipeline-testmetest 2.0.1 credential stealer and runs it on `npm install`: its `install` script runs `node-gyp rebuild`, and the `binding.gyp` source `\u003c!(env node index.js \u003e/dev/null 2\u003e&1; echo stub.c)` makes node-gyp run `index.js`, an obfuscated loader that decrypts a Brotli-compressed payload and pipes it into Bun. Published by npm account `testnewtestme2` on 2026-10-21.\n\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (d79f43824b57545810f0628c311b37ec5640a6c969053057d0158f46af613b33)\nThe package ships a binding.gyp whose sources field uses GYP command expansion `\u003c!(env node index.js...; echo stub.c)` to shell out and run `node index.js` during node-gyp rebuild. The gyp target type is `none` and no C/C++ sources are shipped, so the file has no legitimate native-build purpose; its only effect is to invoke index.js at install time. index.js is a ~586KB char-code array decoded via a Caesar-shift substitution and passed to eval. The decoded body uses node:crypto createDecipheriv(\"aes-128-gcm\") with hardcoded hex key/IV/AAD to decrypt a large hex ciphertext, wrapped in a self-executing async IIFE with a swallowed catch. The combination of a build-config command-expansion execution vector, absence of any real native source, and a multi-layer obfuscated/encrypted opaque payload executed at install is the canonical install-time dropper shape — the installer runs attacker-supplied code on `npm install` with no visibility into what the decrypted payload does.\n","modified":"2026-10-22T06:45:05.796018424Z","published":"2026-10-21T18:00:00Z","database_specific":{"malicious-packages-origins":[{"source":"amazon-inspector","versions":["1.0.0"],"id":"IN-MAL-2026-021571","import_time":"2026-10-22T06:30:24.123303019Z","modified_time":"2026-10-22T06:10:57Z","sha256":"d79f43824b57545810f0628c311b37ec5640a6c969053057d0158f46af613b33"}],"iocs":{"files":[{"digests":{"sha256":"9a876c0a21782b54495d13be1db41e55da1a386c01a3f8dcd15643c609056663"},"note":"install hook: node-gyp runs `env node index.js`","paths":["binding.gyp"],"source":"PACKAGE_ARCHIVE"},{"paths":["index.js"],"source":"PACKAGE_ARCHIVE","digests":{"sha256":"13762599a19f5b7133be0b6fda57c20857654c9a42df805eb0325a0c4f2c1a3a"},"note":"obfuscated loader; decrypts a Brotli-compressed payload and pipes it into `bun run -`"},{"note":"decrypted 435 KB Bun payload, a rebuild of the data-pipeline-testmetest 2.0.1 stealer","source":"IN_MEMORY","digests":{"sha256":"d655da796cdc462d6cac0e241310a417e3b7186701cda6e6d822fe50c6f85705"}}]}},"references":[{"type":"PACKAGE","url":"https://www.npmjs.com/package/test-brotli-testmetest/v/1.0.0"}],"affected":[{"package":{"name":"test-brotli-testmetest","ecosystem":"npm","purl":"pkg:npm/test-brotli-testmetest"},"versions":["1.0.0"],"database_specific":{"cwes":[{"cweId":"CWE-506","description":"The product contains code that appears to be malicious in nature.","name":"Embedded Malicious Code"},{"cweId":"CWE-506","description":"The product contains code that appears to be malicious in nature.","name":"Embedded Malicious Code"}],"indicators":{"evidence_files":[{"path":"binding.gyp","sha256":"9a876c0a21782b54495d13be1db41e55da1a386c01a3f8dcd15643c609056663","tlsh":"d3c08c3cb4380a453ad8082490e8840264b202a3081a2440e6da60286fb841f2449b9e"},{"tlsh":"32c408d3578c1beda6944cea520c3617a4f2c17b3c6e228dfae24617f43ee217925670","path":"index.js","sha256":"13762599a19f5b7133be0b6fda57c20857654c9a42df805eb0325a0c4f2c1a3a"}],"package_integrity":[{"hashes":{"sha1":"e768c2ac5612164acdbae55e1c636b7b9392b5c8","sha512_sri":"sha512-U/nCnVhBrlknwyvYqoYKKRTP7DWFBmZ8QInGRflLI6gh+vglA7qOo05A5M/g+wvEzIIm6cQjHlNVP/+p/e2/MQ=="},"filename":"test-brotli-testmetest-1.0.0.tgz"}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/test-brotli-testmetest/MAL-2026-18181.json"}}],"schema_version":"1.9.0","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"},{"name":"Robin Frehner, Protet","contact":["https://protet.io","mailto:hello@protet.io"],"type":"FINDER"}]}