cookie-parser-legacynpm

Package name and README impersonate the well-known cookie-parser Express middleware. The source is a near-verbatim copy of cookie-parser, except the legitimate cookie-signature dependency has been replaced with an unknown package moustick pinned to the mutable latest tag (package.json: "moustick": "latest"). index.js requires moustick as signature and invokes signature.unsign(str.slice(2), secrets[i]) at request time on user-supplied cookie values, executing whatever code moustick currently publishes against installer-side cookie secrets and signed values. index.js additionally imports execSync from child_process at the top of the file with no reference anywhere in the cookie-parsing logic — an unusual staging artifact for a pure parsing module. The combination of name-impersonation of a top-tier middleware, silent substitution of a security-critical dependency, and pinning that substitute to a mutable tag means any installer who picks this up thinking it is cookie-parser will resolve and execute arbitrary third-party code controlled by the moustick publisher on every install.

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.