alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Cobalt Strike Domain (asureupdate .tech in TLS SNI)"; flow:established,to_server; tls.sni; content:"asureupdate.tech"; bsize:16; fast_pattern; reference:url,www.cert.ssi.gouv.fr/uploads/CERTFR-2021-CTI-009.pdf; reference:md5,80447e4ec87e319bdc6895e04b18363e; classtype:domain-c2; sid:2034393; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_11_09, deployment Perimeter, malware_family Cobalt_Strike, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_11_09, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)