ET MALWARE Cobalt Strike Malleable C2 (Microsoft Update GET)

Query · suricata

flow:established,to_server;
urilen:220;
http.method;
content:"GET";
http.uri;
content:"/c/msdownload/update/others/2016/12/29136388_"; startswith; fast_pattern;
content:".cab"; distance:171; endswith;
http.user_agent;
content:"Windows-Update-Agent/10.0.10011.16384 Client-Protocol/1.40"; bsize:58;
http.header_names;
content:!"Referer";
Raw source ET MALWARE Cobalt Strike Malleable C2 (Microsoft Update GET) · Suricata
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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 Malleable C2 (Microsoft Update GET)";
    flow:established,to_server;
    urilen:220;
    http.method;
    content:"GET";
    http.uri;
    content:"/c/msdownload/update/others/2016/12/29136388_"; startswith; fast_pattern;
    content:".cab"; distance:171; endswith;
    http.user_agent;
    content:"Windows-Update-Agent/10.0.10011.16384 Client-Protocol/1.40"; bsize:58;
    http.header_names;
    content:!"Referer";
    reference:url,github.com/rsmudge/Malleable-C2-Profiles/blob/master/normal/microsoftupdate_getonly.profile;
    classtype:command-and-control;
    sid:2032752; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2020_09_18, deployment Perimeter, deployment SSLDecrypt, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, updated_at 2020_11_19, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1001, mitre_technique_name Data_Obfuscation;
)

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