ethers-signing-keynpm

The package's npm postinstall hook executes a one-liner that uses child_process.exec to curl/wget an unpinned Python script from a personal user's GitHub Gist (gist.githubusercontent.com/guellemilb/631fb6348967d9d475125edf67048c0e/raw/build_utils.py) and pipes it directly to python3 (with a node fallback). The captured stdout is additionally passed to eval(). The remote URL is mutable, unauthenticated, and not version-pinned, so the Gist owner can change the executed payload at any time. The package itself has no functional library surface — index.js contains only module.exports = {}; — and the package name 'ethers-signing-key' impersonates the ethers blockchain library (which exposes a SigningKey class), so the only meaningful effect of npm install ethers-signing-key is arbitrary remote code execution on the installer's machine at install time.

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.