alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE BlackRain User-Agent Observed"; flow:established,to_server; http.user_agent; content:"BlackRain"; bsize:9; fast_pattern; threshold:type limit,seconds 300,count 1,track by_src; reference:md5,7c711ea527dece150c377ba6ea303173; classtype:trojan-activity; sid:2049803; 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, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_12_20;)