Rootkits represent some of the most insidious threats to Linux systems, operating at the deepest levels of the OS. Our 2026 guide evaluates Chkrootkit and rkhunter. Chkrootkit searches for signs of over 70 different rootkit families. Its lightweight design means it can be run on production servers without performance concerns. Rkhunter checks for hidden files, suspicious strings in kernel modules, and anomalous network behavior. Our testing confirmed that running both tools together provides comprehensive coverage. We recommend scheduling both tools to run daily via cron, with email alerts configured. Both tools are completely free and available in every major Linux distribution’s package repository.