alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Malleable C2 Profile (Teams) M2"; flow:established,to_server; http.method; content:"GET"; http.header; header_lowercase; content:"authentication|3a 20|skypetoken|3d|eyJhbGciOi"; fast_pattern; pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/R"; http.accept; bsize:4; content:"json"; http.referer; bsize:29; content:"https://teams.microsoft.com/_"; reference:url,www.blackarrow.net/leveraging-microsoft-teams-to-persist-and-cover-up-cobalt-strike-traffic/; classtype:command-and-control; sid:2032976; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_05_18, deployment Perimeter, deployment SSLDecrypt, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2024_04_30, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;)