ET RETIRED TrueBot/Silence.Downloader CnC Checkin 4

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET RETIRED TrueBot/Silence.Downloader CnC Checkin 4";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:".php"; endswith;
    http.request_body;
    content:"q="; depth:2;
    pcre:"/^q=(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/i";
    http.user_agent;
    content:"Mozilla/112.0"; startswith; fast_pattern;
    http.header_names;
    content:!"Referer";
    content:!"Accept";
    reference:md5,f1a4e74e72390ef98c23f19589d3c7cd;
    reference:url,blog.talosintelligence.com/breaking-the-silence-recent-truebot-activity/;
    classtype:command-and-control;
    sid:2045299; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_05_02, deployment Perimeter, deployment SSLDecrypt, former_category MALWARE, malware_family TrueBot, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_04_17, reviewed_at 2025_04_17;
    target:src_ip;
)