Rule History

alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET PHISHING Observed TyKit Domain (segy .zip in TLS SNI)"; flow:established,to_server; tls.sni; bsize:8; content:"segy.zip"; fast_pattern; reference:url,any.run/cybersecurity-blog/tykit-technical-analysis/; classtype:social-engineering; sid:2065372; rev:1; metadata:attack_target Client_Endpoint, created_at 2025_10_23, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Phishing, tag Description_Generated_By_Proofpoint_Nexus, tag Tykit, updated_at 2025_10_23, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1566, mitre_technique_name Phishing;)