ET MALWARE Possible PDF Dictionary Entry with Hex/Ascii replacement

Query · suricata

flow:established,from_server;
file_data;
content:"%PDF-"; fast_pattern; within:5;
content:"obj";
pcre:"/^[\r\n\s]*?<<(?:(?!>>).)+?\/[a-zA-Z\d]*?#(?:[46][1-9a-fA-F]|[57][\daA])(?:[a-zA-Z\d])*?#(?:[46][1-9a-fA-F]|[57][\daA])/Rsi";
Raw source ET MALWARE Possible PDF Dictionary Entry with Hex/Ascii replacement · 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 MALWARE Possible PDF Dictionary Entry with Hex/Ascii replacement";
    flow:established,from_server;
    file_data;
    content:"%PDF-"; fast_pattern; within:5;
    content:"obj";
    pcre:"/^[\r\n\s]*?<<(?:(?!>>).)+?\/[a-zA-Z\d]*?#(?:[46][1-9a-fA-F]|[57][\daA])(?:[a-zA-Z\d])*?#(?:[46][1-9a-fA-F]|[57][\daA])/Rsi";
    classtype:trojan-activity;
    sid:2017899; rev:4;
    metadata:created_at 2013_12_24, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;
)

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