ET MALWARE Cobalt Strike Beacon CnC

Query · suricata

flow:established,to_server;
http.method;
content:"GET";
http.uri;
content:".css"; endswith;
http.cookie;
content:"lu="; fast_pattern; startswith;
pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/R";
http.header_names;
content:!"Referer";
Raw source ET MALWARE Cobalt Strike Beacon CnC · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Cobalt Strike Beacon CnC";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:".css"; endswith;
    http.cookie;
    content:"lu="; fast_pattern; startswith;
    pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/R";
    http.header_names;
    content:!"Referer";
    reference:md5,ce73caaa42bd465a37802ad3457d2081;
    reference:url,medium.com/walmartglobaltech/nimar-loader-4f61c090c49e;
    classtype:command-and-control;
    sid:2031810; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2021_03_04, deployment Perimeter, deployment SSLDecrypt, confidence Medium, signature_severity Major, tag c2, updated_at 2021_03_04, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;
)

Detection rules belong to the projects that publish them and remain under their own licenses. This site indexes and links to them; it claims no rights in them.