alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed StrongPity CnC Domain in TLS SNI"; flow:established,to_server; tls.sni; content:"system2-access-sec43.com"; bsize:24; reference:url,blog.talosintelligence.com/2020/06/promethium-extends-with-strongpity3.html; classtype:domain-c2; sid:2030423; rev:2; metadata:affected_product Web_Browsers, created_at 2020_07_01, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag StrongPity, tag SSL_TLS_SNI, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_11_17, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)