testmgkregmenpm

npm package [email protected] uses a binding.gyp whose sources field employs GYP command-expansion (<!(env node index.js...; echo stub.c)) to run node index.js during node-gyp rebuild, which npm invokes automatically when a binding.gyp is present. No native source files (.c/.cc/.cpp/.h) are shipped, so the binding.gyp exists solely to trigger install-time code execution rather than to build a native addon. The executed index.js is a 2.9 MB single-IIFE wrapper: an outer Caesar-cipher (ROT k=4) layer is passed to eval, and the decoded body then AES-128-GCM-decrypts hardcoded hex ciphertexts with a hardcoded key/IV/authTag and evals the plaintext. The multi-layer ROT->eval->AES->eval construction has no legitimate purpose and conceals the runtime payload from static review. The result is that npm install testmgkregme causes opaque attacker-authored JavaScript to execute on the installer's machine with the installer's privileges.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.