alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed MageCart CnC Domain in TLS SNI"; flow:established,to_server; tls.sni; content:"sucuil.net"; bsize:10; reference:url,twitter.com/felixaime/status/1301090258671542272; classtype:trojan-activity; sid:2030828; rev:1; metadata:attack_target Client_Endpoint, created_at 2020_09_02, deployment Perimeter, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_02, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)