ET RETIRED BunnyLoader CnC Checkin - Heartbeat

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET RETIRED BunnyLoader CnC Checkin - Heartbeat";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/Bunny/Heartbeat.php?"; startswith; fast_pattern;
    content:"country=";
    content:"ip=";
    content:"host=";
    pcre:"/^[A-Z0-9]{4,8}/R";
    content:"ver=";
    pcre:"/^\d\.\d/R";
    content:"system=Windows";
    content:"privs=";
    content:"av=";
    flowbits:set,ET.BunnyLoader.Heartbeat;
    threshold:type limit, track by_src, count 1, seconds 300;
    reference:url,www.zscaler.com/blogs/security-research/bunnyloader-newest-malware-service;
    reference:md5,dbf727e1effc3631ae634d95a0d88bf3;
    classtype:trojan-activity;
    sid:2048402; rev:4;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, created_at 2023_10_04, deployment Perimeter, former_category MALWARE, malware_family BunnyLoader, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_04_17, reviewed_at 2025_04_17;
    target:src_ip;
)