We use Lynis as automated security resource for auditing, system hardening and compliance testing: 

Lynis is a battle-tested security tool for systems running Linux, macOS, or Unix-based operating system. It performs an extensive health scan of your systems to support system hardening and compliance testing. The project is open source software with the GPL license and available since 2007.

Lynis performs hundreds of individual tests. Each test will help to determine the security state of the system. Most tests are written in shell script and have a unique identifier.