alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/BlackRain CnC Activity"; flow:established,to_server; http.method; content:"POST"; http.header_names; content:!"Referer"; http.request_body; content:"action="; startswith; content:"&botID="; fast_pattern; pcre:"/^(?:[a-z0-9]{40})$/R"; threshold:type limit,seconds 300,count 1,track by_src; reference:md5,7c711ea527dece150c377ba6ea303173; classtype:trojan-activity; sid:2049802; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_12_20, deployment Perimeter, malware_family Win32_BlackRain, confidence High, signature_severity Critical, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_12_20;)