DGA Domain Query - High Entropy Random Subdomain

Darshan Thummar@Mighty

•updated Jun 12, 2026•1•0•89

This rule detects DNS queries for domains that exhibit characteristics of Domain Generation Algorithms (DGAs). Specifically, it looks for DNS queries where the queried domain consists of a random-looking subdomain (12 to 24 lowercase alphanumeric characters) followed by common top-level domains such as .com, .net, .org, .info, or .biz. The rule uses a thresholding mechanism to trigger an alert if 10 such queries are observed from the same source IP within a 60-second window, indicating potential DGA activity often associated with botnets or malware for command and control.