chai-mocksnpm

The package masquerades as a pino-style logger middleware but is a remote code loader. When the exported middleware is invoked, index.js spawns a detached node./lib/caller.js child process. caller.js fetches https://jsonkeeper.com/b/U2BTS (with a second URL https://jsonkeeper.com/b/XRGF3 stored base64-encoded in a variable named DEV_API_KEY to disguise it as a configuration constant), reads the cookie field of the JSON response, and executes it via new Function.constructor('require', s)(require) — arbitrary attacker-controlled code execution with full Node require access on the consumer's machine. jsonkeeper.com is an anonymous, mutable paste service; the contents can be changed by the author at any time without republishing the package. The package name (chai-mocks) and bait API surface (exports pino, references DEFAULT_LEVELS/redact/customLevels, scripts named smoke:pino) are unrelated to the package's author identity (Alexus111 [email protected]) and are designed to lure developers who mistype or confuse it with the chai or pino logger ecosystems. The base64-obfuscated URLs and fake DEV_API_KEY/DEV_SECRET_KEY variable names confirm intent to hide the C2 endpoint.

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.