alert dns $HOME_NET any -> any any (msg:"ET INFO Network Tunneling Service in DNS Lookup (zrok .io)"; dns.query; dotprefix; content:".zrok.io"; nocase; endswith; reference:url,github.com/anderspitman/awesome-tunneling?tab=readme-ov-file; classtype:misc-activity; sid:2066013; rev:1; metadata:affected_product Any, attack_target Client_and_Server, created_at 2025_12_04, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, tag Network_Tunneling, updated_at 2025_12_04, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1572, mitre_technique_name Protocol_Tunneling;)