ET MALWARE Oyster Backdoor CnC Checkin M2

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Oyster Backdoor CnC Checkin M2";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri; bsize:4;
    content:"/reg";
    http.user_agent; bsize:14;
    content:"WordPressAgent"; fast_pattern;
    http.header_names;
    content:"|0d 0a|x-amz-cf-id|0d 0a|";
    content:"|0d 0a|Content-Encoding|0d 0a|";
    content:"|0d 0a|Content-Length|0d 0a|";
    reference:url,malpedia.caad.fkie.fraunhofer.de/details/win.broomstick;
    reference:url,www.cyberproof.com/blog/oyster-backdoor-the-malvertising-menace-masquerading-as-popular-tools/;
    reference:url,www.catonetworks.com/blog/cato-ctrl-oyster-malware-campaign/;
    classtype:trojan-activity;
    sid:2064627; rev:1;
    metadata:attack_target Client_and_Server, created_at 2025_09_12, deployment Perimeter, malware_family Oyster_Backdoor, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_09_12, mitre_tactic_id TA0037, mitre_tactic_name Command_And_Control, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;
    target:src_ip;
)