Versions (3)
Version DetailsCurrent
Rev: 1 • Mar 16, 2022, 12:00 PMET MALWARE Observed Cobalt Stike CnC Domain (nirsoft .me in TLS SNI)
alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Cobalt Stike CnC Domain (nirsoft .me in TLS SNI)"; flow:established,to_server; tls.sni; content:"nirsoft.me"; bsize:10; fast_pattern; reference:md5,aa5e8268e741346c76ebfd1f27941a14; reference:url,cert.gov.ua/article/37704; classtype:domain-c2; sid:2035470; rev:1; metadata:attack_target Client_Endpoint, created_at 2022_03_16, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_03_16, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)
Mar 16, 2022, 12:00 PM
Mar 16, 2022, 12:00 PM
Sep 21, 2024, 3:00 AM
Sep 4, 2025, 9:34 PM
rules/emerging-malware.rules