alert dns $HOME_NET any -> any any (msg:"ET INFO FUNNULL CDN Domain in DNS Lookup (* .funnull .com)"; dns.query; dotprefix; content:".funnull.com"; nocase; endswith; threshold:type limit, count 1, seconds 120, track by_src reference:url,www.silentpush.com/blog/triad-nexus-funnull/; reference:url,silentpush.com/blog/infrastructure-laundering/; classtype:bad-unknown; sid:2061962; rev:1; metadata:attack_target Client_and_Server, created_at 2025_04_29, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2025_04_29, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1189, mitre_technique_name Drive_by_Compromise;)