ET MALWARE Cobalt Strike Activity (GET)

Query · suricata

flow:established,to_server;
http.method;
content:"GET";
http.uri;
content:"/oscp/"; startswith; fast_pattern;
pcre:"/^[a-z]{256}$/R";
http.header_names;
content:"|0d 0a|Accept|0d 0a|Host|0d 0a|User-Agent|0d 0a|Connection|0d 0a|Cache-Control|0d 0a 0d 0a|"; bsize:57;
Raw source ET MALWARE Cobalt Strike 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 -> $EXTERNAL_NET any (
    msg:"ET MALWARE Cobalt Strike Activity (GET)";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri;
    content:"/oscp/"; startswith; fast_pattern;
    pcre:"/^[a-z]{256}$/R";
    http.header_names;
    content:"|0d 0a|Accept|0d 0a|Host|0d 0a|User-Agent|0d 0a|Connection|0d 0a|Cache-Control|0d 0a 0d 0a|"; bsize:57;
    reference:url,www.cert.ssi.gouv.fr/cti/CERTFR-2021-CTI-009;
    reference:md5,f790bea81673806479e30337629fa605;
    classtype:trojan-activity;
    sid:2034358; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2021_11_08, deployment Perimeter, deployment SSLDecrypt, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_11_08;
)

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