ET WEB_SERVER Possible Darkleech C2

Query · suricata

flow:established,to_server;
http.uri;
content:"/blog/?"; depth:7; fast_pattern;
content:"&utm_source="; distance:0;
pcre:"/^\/blog\/\?[a-z]{3,20}+\&utm_source=\d+\x3a\d+\x3a\d+$/";
http.host;
pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/";
http.header_names;
content:!"Referer|0d 0a|";
Raw source ET WEB_SERVER Possible Darkleech C2 · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $HTTP_SERVERS any -> $EXTERNAL_NET any (
    msg:"ET WEB_SERVER Possible Darkleech C2";
    flow:established,to_server;
    http.uri;
    content:"/blog/?"; depth:7; fast_pattern;
    content:"&utm_source="; distance:0;
    pcre:"/^\/blog\/\?[a-z]{3,20}+\&utm_source=\d+\x3a\d+\x3a\d+$/";
    http.host;
    pcre:"/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/";
    http.header_names;
    content:!"Referer|0d 0a|";
    reference:url,blog.sucuri.net/2015/12/evolution-of-pseudo-darkleech.html;
    classtype:command-and-control;
    sid:2022260; rev:4;
    metadata:created_at 2015_12_14, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_11_03;
)

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