{"id":"MAL-2026-17171","summary":"Malicious code in agency-testts (npm)","details":"\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (ac3bbe97b41f8d8d1a74e9f369318620c08d648365a4e78d49d1da31d085531d)\npackage.json declares a postinstall lifecycle hook `wscript.exe 4444.vbs` that auto-runs on `npm install` on Windows. The bundled 4444.vbs is a ~674KB script containing large opaque base64 blobs and an AES key/IV pair (`stateFKK`, `manifestGCP`) which it uses at runtime to decrypt an embedded payload via `CreateDecryptor().TransformFinalBlock` and hand it to `C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe` for execution. After staging, the script self-cleans with `cmd.exe /c ping 127.0.0.1 -n 8 \u003enul & del /f /q... & rmdir /s /q...` to remove its own artifacts. Cover-story comments label the script a `Sync Agent — diagnostic telemetry collector` from a fictitious `Wingtip Toys Corporation`, but the code performs no telemetry-shaped behavior — it decrypts and executes an opaque payload. The package ships no other functionality; installing it on Windows results in arbitrary attacker code running under the installer's user account.\n","modified":"2026-09-25T03:00:06.512644878Z","published":"2026-09-25T02:38:03Z","database_specific":{"malicious-packages-origins":[{"import_time":"2026-09-25T02:45:28.358535604Z","modified_time":"2026-09-25T02:38:03Z","sha256":"ac3bbe97b41f8d8d1a74e9f369318620c08d648365a4e78d49d1da31d085531d","source":"amazon-inspector","versions":["1.0.0"],"id":"IN-MAL-2026-020526"}]},"references":[{"type":"PACKAGE","url":"https://www.npmjs.com/package/agency-testts/v/1.0.0"}],"affected":[{"package":{"name":"agency-testts","ecosystem":"npm","purl":"pkg:npm/agency-testts"},"versions":["1.0.0"],"database_specific":{"indicators":{"evidence_files":[{"tlsh":"d4d0a7164c44556329f487a409714406b5514f1f11304c47b2fb741884e76b24889f17","path":"package.json","sha256":"ef4b97e89a4aa7ac6165ef9d8eaa769aa5d541b92e8ec74fa2d4d48e4b18b11c"},{"sha256":"4c3218af4966a2fcb590bb3a1a459f12d626e400f036651986044306b967b1fb","tlsh":"64e4013a1e1c4725a6aa6d8ca7e30077adef2e0b11117c877f5d1c511bf2296e4e3a1c","path":"4444.vbs"}],"package_integrity":[{"hashes":{"sha1":"d90958337c1fe793543cac3f3565d6be58ec11bf","sha512_sri":"sha512-UqLBFzm1pKNhB3Qtmt77AU60nIlKgxXy4qgdU+FsZwUeNOJdsuFawWgbZIXVwAtYNs/f3UzEf/XrdTCI0BSriw=="},"filename":"agency-testts-1.0.0.tgz"}]},"source":"https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/agency-testts/MAL-2026-17171.json","cwes":[{"name":"Embedded Malicious Code","cweId":"CWE-506","description":"The product contains code that appears to be malicious in nature."}]}}],"schema_version":"1.9.0","credits":[{"name":"Amazon Inspector","contact":["inspector-research@amazon.com"],"type":"FINDER"}]}