ET MALWARE Win32/TrojanDownloader.Agent.FC CnC Activity

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/TrojanDownloader.Agent.FC CnC Activity";
    flow:established,to_server;
    http.start;
    content:"POST /loader/gate HTTP/1.0|0d 0a|Host|3a 20|"; fast_pattern;
    http.user_agent;
    content:!"|20|";
    http.referer;
    content:!"|2e|";
    http.request_body;
    content:"data="; startswith;
    pcre:"/^(?:[a-zA-Z0-9+/]{4})*(?:[a-zA-Z0-9+/]{2}==|[a-zA-Z0-9+/]{3}=|[a-zA-Z0-9+/]{4})$/R";
    reference:md5,d8dbaecab080b40e7782b10affb630f4;
    classtype:command-and-control;
    sid:2030678; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_08_12, deployment Perimeter, malware_family Win32_TrojanDownloader_Agent_FC, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_12;
)