OSSEC is an Open Source Host-based Intrusion Detection System that performs log analysis, file integrity checking, policy monitoring, rootkit detection, real-time alerting and active response.
Updated, there are repos in the new format for u20, u22, and u24 for both amd64 and arm64 systems. You might need to run the atomic installer again to get the new repo file
The repo/apt data for Ubuntu Jammy seems to missing on the atomicorp site. There is for Ubuntu Focal.