alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed DarkSide Ransomware Domain (catsdegree .com in TLS SNI)"; flow:established,to_server; tls.sni; content:"catsdegree.com"; bsize:14; fast_pattern; reference:md5,f00aded4c16c0e8c3b5adfc23d19c609; classtype:domain-c2; sid:2032939; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_05_11, deployment Perimeter, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_05_11, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)