ET MALWARE Cobalt Strike Beacon Activity (GET)

Query · suricata

flow:established,to_server;
content:"|20|/logo|20|HTTP/1."; fast_pattern;
http.method;
content:"GET";
http.cookie;
content:"lu="; 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";
content:"|0d 0a|Accept|0d 0a|Host|0d 0a|Connection|0d 0a|Accept-Encoding|0d 0a|"; startswith;
Raw source ET MALWARE Cobalt Strike Beacon Activity (GET) · 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 -> $EXTERNAL_NET any (
    msg:"ET MALWARE Cobalt Strike Beacon Activity (GET)";
    flow:established,to_server;
    content:"|20|/logo|20|HTTP/1."; fast_pattern;
    http.method;
    content:"GET";
    http.cookie;
    content:"lu="; startswith;
    pcre:"/^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/R";
    http.header_names;
    content:!"Referer";
    content:"|0d 0a|Accept|0d 0a|Host|0d 0a|Connection|0d 0a|Accept-Encoding|0d 0a|"; startswith;
    reference:md5,45ec8cee2c028e47d3bba2e14a93a957;
    classtype:trojan-activity;
    sid:2032336; rev:2;
    metadata:attack_target Client_Endpoint, created_at 2021_03_25, deployment Perimeter, confidence Medium, signature_severity Major, tag c2, updated_at 2021_03_26, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;
)

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