The npm package 'only-warn' version 9.9.0 contains malicious code that installs a dependency from a custom domain which executes an information stealer during installation. This malware targets sensitive tokens related to npm, git, and CI/CD environments. Any system with this package installed or running is considered fully compromised, necessitating immediate rotation of all secrets and keys from a secure machine. Removal of the package alone does not guarantee eradication of all malicious components.