ET MALWARE Win32/Valak - Plugin Data Exfil

Query · suricata

flow:established,to_server;
http.method;
content:"POST";
http.uri; bsize:>60;
content:"bm9uY2UyP"; fast_pattern;
content:"cGx1Z2luP"; distance:55;
content:".html"; endswith;
http.header_names;
content:!"Referer";
Raw source ET MALWARE Win32/Valak - Plugin Data Exfil · 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 Win32/Valak - Plugin Data Exfil";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri; bsize:>60;
    content:"bm9uY2UyP"; fast_pattern;
    content:"cGx1Z2luP"; distance:55;
    content:".html"; endswith;
    http.header_names;
    content:!"Referer";
    reference:md5,c254b4f261a6f426c282ed8858a7bee0;
    reference:url,medium.com/@prsecurity_/casual-analysis-of-valak-c2-3497fdb79bf7;
    classtype:command-and-control;
    sid:2029197; rev:1;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_12_23, deployment Perimeter, malware_family Win32_Valak, performance_impact Low, confidence High, signature_severity Major, updated_at 2019_12_23;
)

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