alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE GCleaner Downloader Activity M4"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".php?pub=mix"; fast_pattern; content:"&user="; distance:0; http.content_type; content:"application/x-www-form-urlencoded"; bsize:33; http.user_agent; content:"-"; offset:2; depth:1; content:"-"; distance:2; within:1; content:"-"; distance:2; within:1; content:"-"; distance:2; within:1; content:"-"; distance:1; within:1; isdataat:!2,relative; bsize:15; reference:md5,ff4ae9d00058d3e9d5034d043387c4be; reference:url,medium.com/csis-techblog/gcleaner-garbage-provider-since-2019-2708e7c87a8a; classtype:command-and-control; sid:2033795; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_08_25, deployment Perimeter, malware_family GCleaner, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_25;)