alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed CobaltStrike CnC Domain in TLS SNI"; flow:to_server,established; tls.sni; content:"advancedanalysis.be"; bsize:19; endswith; classtype:domain-c2; sid:2030456; rev:1; metadata:created_at 2020_07_03, deployment Perimeter, malware_family Cobalt_Strike, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_07_03, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)