Can you suggest a Linux folder auditing system?

Question

linux

There is a folder / var / www - where a bunch of sites are located, on completely different CMS.
Somehow it got infected - (through joomla I guess) - and the malicious redirect appeared on all sites.
Now everything has been cleaned up, it is still difficult to reorganize, a temporary crutch is needed, as in the days of DOS I remember there were antiviruses that checked the checksum of changed files at each boot.
The same thing is needed now under Linux, with a flexible system of exclusion folders. Some kind of script. ON.
Thank you.

Answer 1

Usually such a problem is solved from two sides:
Security - in order to prevent all sites from being infected, you need to configure your web server so that each site is a separate user without access rights to files of other sites. to dig towards suphp suexec and similar solutions.
Version control - each site, except for folders with caches and content, is uploaded to the version control system, this will make it easy to figure out if something has changed.

Answer 2

Can you suggest a Linux folder auditing system?

Native auditctl.