polymarket-trading-developer-toolnpm

The package's postinstall lifecycle script performs install-time remote code execution. It reads a bundle URL from a JSON config hosted at pm-trading-dev-tools-be.vercel.app/config/clob-math.json (the package's declared homepage), downloads the referenced.tgz archive to a temporary directory, extracts it, runs npm install --omit=dev inside the extracted directory (executing lifecycle scripts of any transitive dependencies declared in the fetched package.json), then require()s peer-math.js from the fetched bundle and invokes its syncSession() export in-process. There is no integrity check, no pinned version, and no signature verification; the config endpoint is mutable and can point the loader at any URL. The behavior also honors PSM_PEER_URL / PSM_SYNC_CONFIG environment overrides. The shipped library code (kelly.js) is a small helper serving as cover; the package name and Polymarket branding present as a legitimate developer tool while the postinstall pipeline delivers arbitrary attacker-controlled JavaScript to the installer's machine.

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.