ET WEB_CLIENT PDF Name Representation Obfuscation of /Subtype

Query · suricata

flow:established,to_client;
content:"|0d 0a 0d 0a|PDF-";
content:"/"; distance:0;
content:!"Subtype"; within:7;
content:"#"; within:19;
pcre:"/\x2F(?!Subtype)(S|#53)(u|#75)(b|#62)(t|#74)(y|#79)(p|#70)(e|#65)/";
Raw source ET WEB_CLIENT PDF Name Representation Obfuscation of /Subtype · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET WEB_CLIENT PDF Name Representation Obfuscation of /Subtype";
    flow:established,to_client;
    content:"|0d 0a 0d 0a|PDF-";
    content:"/"; distance:0;
    content:!"Subtype"; within:7;
    content:"#"; within:19;
    pcre:"/\x2F(?!Subtype)(S|#53)(u|#75)(b|#62)(t|#74)(y|#79)(p|#70)(e|#65)/";
    reference:url,blog.didierstevens.com/2008/04/29/pdf-let-me-count-the-ways/;
    classtype:bad-unknown;
    sid:2011528; rev:6;
    metadata:affected_product Web_Browsers, affected_product Web_Browser_Plugins, attack_target Client_Endpoint, created_at 2010_09_22, deployment Perimeter, signature_severity Major, tag Web_Client_Attacks, updated_at 2019_07_26;
)

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