alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Malleable C2 (Custom)"; flow:established,to_server; http.method; content:"GET"; http.uri; bsize:277; content:"/api/3.1/query?style="; startswith; fast_pattern; pcre:"/^[a-z]{256}$/R"; http.header; content:"Referer|3a 20|https://www.google.com|0d 0a|Accept|3a 20|*/*|0d 0a|Content-Type|3a 20|application/x-www-form-urlencoded|0d 0a|Content-Transfer-Encoding|3a 20|base64|0d 0a|"; reference:url,twitter.com/CyberRaiju/status/1249272772963864576; reference:md5,79bbe1365fb7532613823ce3e0cac499; classtype:command-and-control; sid:2029977; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_04_20, deployment Perimeter, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2020_04_20, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;)