I published a blog post about testing Security Onion's DNS C2 detection capabilities: https://akusilvennoinen.fi/posts/security-onion-dns-c2/
Sliver DNS C2 traffic is not detected by Security Onion 2.4.111 using the default detection rules.
None of the Security Onion detections (at least from the default sources) are statistical anomaly detections or some other behavioral detections, and detecting DNS C2 traffic requires a statistical or some other behavioral method to avoid an excessively high number of false positives.
Security Onion 2.4.111 contains Zeek (formerly known as Bro), a network traffic analysis framework. Zeek can be used for defining statistical detections with its event-driven scripting language.
Jeremy Baggs has developed Zeek scripts for detecting anomalous DNS traffic. The scripts are available at https://github.com/jbaggs/anomalous-dns.
The blog post describes a method for adding these scripts to Security Onion.
#securityonion #sliver #zeek #detectionengineering