Logger

Lynis generates multiple logs. Besides a profile containing the respective test scenario, it generates a logfile and a report. Lynis shows you the search paths for the individual files after starting the tests.

The report is the most important of these files. It not only contains a detailed list of all loaded kernel modules, data on the network interfaces, and the directory structures, but it also includes all of the installed packages, cron jobs, and the tests that have been run. These do not appear in plain text like in the program output, but with their internal designations. Lynis also outputs detailed information about the services loaded by the init system.

The report also contains several suggestions on how to harden the current system against attacks. However, these suggestions are somewhat cluttered and unstructured in the report. The suggestion tag at the beginning of each line marks the individual suggestions.

Profiles

Lynis supports the use of different profiles. You can view a list of all existing profiles with lynis show profiles. The preset profile uses all available options. If you only want to test certain components or services, you can create an additional profile for this purpose. There are no restrictions on the number of profiles.

The profiles are simple text files, which can be managed with any text editor. However, be careful not to modify the original profile. To use a specific profile during a test run, specify its name as an option when calling Lynis. To perform a test run with a specific profile, type the following at the prompt:

lynis audit --profile <profile>

When you assign names to new profiles that you generate from the default profile as a template, you should include the components to be tested in the name. For example, you can create specific profiles for different installations, but also group different server services, such as web or mail servers, into separate profiles. The security level can also be taken into account in individual profiles.

Regular Scanning

Especially in a corporate environment, you will want to run security scans regularly. A cron job gives you the ability to run Lynis at fixed intervals. To do this, the application offers the --cronjob call parameter, which does a complete scan of the system. You also need to generate a matching script and create the associated paths to be able to save the report.

Automated tests will then run at regular intervals without any user interaction. The software also removes all special characters from the report to facilitate processing downstream. Users of the Enterprise variant also have the option to use the --upload parameter to send the report to their own Lynis instance for auditing and documentation purposes [5].