alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Malleable C2 OCSP Profile"; flow:to_server,established; http.method; content:"GET"; http.uri; content:"/oscp/"; fast_pattern; depth:6; pcre:"/^\/oscp\/[a-z]+$/"; http.header; content:"Host|3a 20|ocsp.verisign.com|0d 0a|Accept"; depth:31; content:"Microsoft-CryptoAPI/6.1"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,2ba2e7af1246da08e4fd7345c7207b59; reference:url,github.com/rsmudge/Malleable-C2-Profiles/blob/master/normal/oscp.profile; classtype:command-and-control; sid:2032750; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2017_05_15, deployment Perimeter, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2020_08_06, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;)