alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed DOUBLEBACK CnC Domain (bestcake .ca in TLS SNI)"; flow:established,to_server; tls.sni; content:"bestcake.ca"; bsize:11; fast_pattern; reference:url,twitter.com/k3dg3/status/1532454383631450115; classtype:domain-c2; sid:2036822; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2022_06_03, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_06_03, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)