ET MALWARE NimPlant Task Activity (GET)

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE NimPlant Task Activity (GET)";
    flow:established,to_server;
    flowbits:set,ET.nimplant;
    urilen:5;
    http.method;
    content:"GET";
    http.uri;
    content:"/task"; fast_pattern;
    http.accept_enc;
    content:"gzip"; bsize:4;
    http.header;
    content:"|0d 0a|X-Identifier|3a 20|";
    pcre:"/^[a-zA-Z]{8}\r\n/R";
    http.header_names;
    content:"|0d 0a|User-Agent|0d 0a|X-Identifier|0d 0a|Host|0d 0a 0d 0a|";
    content:!"Referer";
    threshold:type both, count 1, seconds 120, track by_src;
    reference:url,github.com/chvancooten/NimPlant;
    classtype:trojan-activity;
    sid:2044350; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2023_02_27, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_02_27;
    target:src_ip;
)