ET MALWARE Possible Kelihos Infection Executable Download With Malformed Header

Query · suricata

flow:established,from_server;
http.header;
content:"Last-Modified|3a|";
http.header.raw;
pcre:"/^Last-Modified\x3a(?:\s[^\r\n]{2}|[^\r\n\s]{3}),/m";
file.data;
content:"MZ"; within:2;
byte_jump:4,58,relative,little;
content:"PE|00 00|"; fast_pattern; distance:-64; within:4;
Raw source ET MALWARE Possible Kelihos Infection Executable Download With Malformed Header · 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 $EXTERNAL_NET any -> $HOME_NET any (
    msg:"ET MALWARE Possible Kelihos Infection Executable Download With Malformed Header";
    flow:established,from_server;
    http.header;
    content:"Last-Modified|3a|";
    http.header.raw;
    pcre:"/^Last-Modified\x3a(?:\s[^\r\n]{2}|[^\r\n\s]{3}),/m";
    file.data;
    content:"MZ"; within:2;
    byte_jump:4,58,relative,little;
    content:"PE|00 00|"; fast_pattern; distance:-64; within:4;
    classtype:trojan-activity;
    sid:2018241; rev:3;
    metadata:created_at 2014_03_09, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_04_28;
)

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