alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE GCleaner Downloader - Payload Response"; flow:established,to_client; http.header; content:"dllENCR.dll|22 3b 0d 0a|"; fast_pattern; content:"Content-Transfer-Encoding|3a 20|binary|0d 0a|"; content:"Content-Type|3a 20|application/octet-stream|0d 0a|"; pcre:"/^Content-Disposition\x3a\x20attachment\x3b\x20filename\x3d\x22[a-zA-Z0-9]+dllENCR.dll\x22\x3b[\r\n]+$/mi"; reference:md5,780099266c4cf79fbf344297b0a4e29e; classtype:trojan-activity; sid:2044037; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2022_12_06, deployment Perimeter, malware_family GCleaner, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_01_31, former_sid 2852925;)