The npm package 'prefer-arrow' 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. Systems with this package installed should be considered fully compromised, and all secrets and keys stored on those systems must be rotated immediately from a different, clean computer. Removal of the package alone does not guarantee elimination of all malicious software introduced.