MAL-2026-12389 Malicious code in github-app-sts-action (npm)

The package declares a preinstall lifecycle hook that runs index.js on npm install. index.js collects host identifiers and system files (os.hostname(), os.userInfo(), home directory, DNS servers, /etc/passwd, /etc/hosts, and package.json contents) and POSTs them via HTTPS to the hardcoded subdomain lncqub6t1loht8b887c8hvcjva13ptdi.oastify.com — a Burp Collaborator out-of-band interaction host used for reconnaissance. There is no advertised functional purpose in the package that would justify this data collection; the code path exists solely to transmit installer host and credential-adjacent file contents to an attacker-controlled 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.