C2 Infrastructure Hidden via Dynamic DNS Service

Darshan Thummar@Mighty

•updated Jun 12, 2026•0•0•6

This rule detects DNS queries to known dynamic DNS services that are frequently abused by C2 infrastructure. Specifically, it looks for queries ending in '.duckdns.org', '.no-ip.com', '.ddns.net', '.hopto.org', or '.zapto.org'. A threshold of 5 queries within 60 seconds from the same source IP is applied to reduce false positives.