Harden any Linux server in minutes. Without locking yourself out.
Hardline audits your server, gives it a grade, and fixes what's weak, one phase at a time. If a change would cut off your SSH access, it undoes itself.
Can't lock you out
SSH and firewall changes are validated first, then undo themselves unless you confirm from a new login. A reboot undoes them too.
Audit first, always
audit changes nothing. apply is a dry run showing the exact diff until you add --commit.
A grade you can share
A–F, weighted by severity. hardline report writes one HTML file: no scripts, no network, safe to email.
Watches for drift
hardline watch re-audits on a timer and fails a systemd unit when anything gets worse, so your alerts fire.
Small, fast, and quiet
Measured on a 2-vCPU Ubuntu 24.04 VM. Runs on Ubuntu 24.04, Ubuntu 22.04, Debian 12 and RHEL 9 / Rocky Linux 9 / AlmaLinux 9.
Try it in 30 seconds
sudo hardline audit # read-only, safe anytime
sudo hardline apply --phase 1 # dry run: shows the diff
sudo hardline apply --phase 1 --commit # write it, start a 2-min timer
sudo hardline confirm # from a NEW ssh sessionGet the binary from the install steps, or read how Hardline keeps your server safe. Every finding hardline audit prints links to its entry in the controls reference.
Source on GitHub · Releases · MIT OR Apache-2.0