ET MALWARE Win32/Valak <v9 - Stage 2 - Request

Query · suricata

flow:established,to_server;
http.method;
content:"GET";
http.uri; bsize:>60;
content:"_aWQ9"; fast_pattern;
content:".html"; endswith;
pcre:"/_aWQ9[a-zA-Z0-9\/]{43,46}(?:JmdpZD|Z2lkP|ZnaWQ9)/";
http.header_names;
content:!"Referer";
Raw source ET MALWARE Win32/Valak <v9 - Stage 2 - Request · 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/Valak <v9 - Stage 2 - Request";
    flow:established,to_server;
    http.method;
    content:"GET";
    http.uri; bsize:>60;
    content:"_aWQ9"; fast_pattern;
    content:".html"; endswith;
    pcre:"/_aWQ9[a-zA-Z0-9\/]{43,46}(?:JmdpZD|Z2lkP|ZnaWQ9)/";
    http.header_names;
    content:!"Referer";
    reference:md5,c254b4f261a6f426c282ed8858a7bee0;
    reference:url,medium.com/@prsecurity_/casual-analysis-of-valak-c2-3497fdb79bf7;
    classtype:command-and-control;
    sid:2029193; rev:2;
    metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_10_22, deployment Perimeter, malware_family Win32_Valak, performance_impact Moderate, confidence High, signature_severity Major, updated_at 2020_12_10;
)

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