ET MALWARE Win32/Ursnif Checkin

Query · suricata

flow:established,to_server;
content:"no-cache|0d 0a 0d 0a 0d 0a|"; endswith;
http.method;
content:"POST";
http.uri;
pcre:"/^(?:\/\w{3,12}){2,4}\?[a-z]{3,12}=(?:[A-Za-z0-9+/\x20]{4})*(?:[A-Za-z0-9+/\x20]{2}==|[A-Za-z0-9+/\x20]{3}=|[A-Za-z0-9+/\x20]{4})$/";
http.header;
content:"|0d 0a|Content-Length|3a 20|2|0d 0a|Connection|3a 20|"; fast_pattern;
http.header_names;
content:!"Referer|0d 0a|";
Raw source ET MALWARE Win32/Ursnif Checkin · 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 -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/Ursnif Checkin";
    flow:established,to_server;
    content:"no-cache|0d 0a 0d 0a 0d 0a|"; endswith;
    http.method;
    content:"POST";
    http.uri;
    pcre:"/^(?:\/\w{3,12}){2,4}\?[a-z]{3,12}=(?:[A-Za-z0-9+/\x20]{4})*(?:[A-Za-z0-9+/\x20]{2}==|[A-Za-z0-9+/\x20]{3}=|[A-Za-z0-9+/\x20]{4})$/";
    http.header;
    content:"|0d 0a|Content-Length|3a 20|2|0d 0a|Connection|3a 20|"; fast_pattern;
    http.header_names;
    content:!"Referer|0d 0a|";
    reference:md5,dfeaae9cb1bc24ac467411955e48483b;
    reference:url,csis.dk/en/csis/news/4472/;
    classtype:command-and-control;
    sid:2019377; rev:8;
    metadata:created_at 2014_10_09, malware_family Win32_Ursnif, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_11_05;
)

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