{"id":"MAL-2026-11141","summary":"Malicious code in lib-streak-math (npm)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (06cd4f53bed50a86ce85bcd8ebcd672ae7e3c01926cac1efd7f3dcf152484267)\nThe package's main entry `index.mjs` presents itself as a math helper but contains a top-level async IIFE that runs on any `require`/`import` of the module. All network destinations, filesystem paths, subprocess names, and Node built-in module names are stored as integer arrays and reconstructed at runtime via a char-code decoder `_D(a) = String.fromCharCode(...a.map((c,i)=\u003e((c-_K[i%3])+256)%256))` with `_K=[11,23,47]`, hiding `fs/promises`, `path`, `child_process`, and `node-fetch` from static inspection. Decoded, the block downloads `https://f004.backblazeb2.com/file/dp8hbvocjd2fpza/helper.tar.gz` into a hidden directory under `AppData/Local/Microsoft/Windows/syscache/helper/`, extracts it with `tar -xzf`, and executes the dropped payload. On Windows, the target user profile is located by scanning `/mnt/c/Users` (WSL), and a launcher `env-setup.cmd` is written into `AppData/Roaming/Microsoft/Windows/Start Menu/Programs/Startup/` so the dropped `vite.exe` auto-launches on every login. On Linux, a `background-service` binary is written to the same hidden path, `chmod 0o755`d, and spawned with `stdio: 'ignore', detached: true` followed by `.unref()`, surviving the parent process. The package's advertised math-library purpose is unrelated to the code that actually runs on import.\n","modified":"2026-07-28T14:37:02.632164108Z","published":"2026-07-28T13:30:11Z","database_specific":{"malicious-packages-origins":[{"sha256":"06cd4f53bed50a86ce85bcd8ebcd672ae7e3c01926cac1efd7f3dcf152484267","source":"amazon-inspector","versions":["1.0.0"],"id":"IN-MAL-2026-010874","import_time":"2026-07-28T14:19:56.910544363Z","modified_time":"2026-07-28T13:30:11Z"}]},"references":[{"type":"PACKAGE","url":"https://www.npmjs.com/package/lib-streak-math/v/1.0.0"}],"affected":[{"package":{"name":"lib-streak-math","ecosystem":"npm","purl":"pkg:npm/lib-streak-math"},"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":[{"sha256":"d3c35c429dde7ce7789db727c146052a41524f031700726e19da0ae1fbdfdba4","tlsh":"f322628245b602b8e52adbd45a5f5019a2b1f01f3f568a847a8de3433f07c349676fac","path":"index.mjs"}],"package_integrity":[{"hashes":{"sha1":"2ecc72530857b5ee201e8cf2844b7500846f78c4","sha512_sri":"sha512-Y+aZLxPyK0QVca5oLwnPSiTep8DHd3YweMz0n8eIM3me+7GHw7eE/fT2YjEUtO2zxy1YJ9R//nbRTsm6RuGwvw=="},"filename":"lib-streak-math-1.0.0.tgz"}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/lib-streak-math/MAL-2026-11141.json"}}],"schema_version":"1.7.5","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"}]}