alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed MageCart Group 12 Domain (toolser .pw in TLS SNI)"; flow:established,to_server; tls.sni; content:"toolser.pw"; bsize:10; fast_pattern; reference:url,lukeleal.com/research/posts/magecart-group-12-toolser-skimmer/; classtype:trojan-activity; sid:2033213; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_07_01, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_01, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)