ET SMTP Incoming SMTP Message with Possibly Malicious MIME Epilogue 2016-05-13 (BadEpilogue)

Query · suricata

flow:to_server,established;
content:"|0d 0a|Content-Type|3a 20|multipart|2f|mixed|3b|"; fast_pattern;
content:"|0d 0a 2d 2d|"; distance:0;
pcre:"/^(?P<boundary>[\x20\x27-\x29\x2b-\x2f0-9\x3a\x3d\x3fA-Z\x5fa-z]{0,69}?[^\x2d])--(?:\x0d\x0a(?!--|\x2e|RSET)[^\r\n]*?)*\x0d\x0a--(?P=boundary)\x0d\x0a/R";
Raw source ET SMTP Incoming SMTP Message with Possibly Malicious MIME Epilogue 2016-05-13 (BadEpilogue) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert tcp any any -> $SMTP_SERVERS [25,587] (
    msg:"ET SMTP Incoming SMTP Message with Possibly Malicious MIME Epilogue 2016-05-13 (BadEpilogue)";
    flow:to_server,established;
    content:"|0d 0a|Content-Type|3a 20|multipart|2f|mixed|3b|"; fast_pattern;
    content:"|0d 0a 2d 2d|"; distance:0;
    pcre:"/^(?P<boundary>[\x20\x27-\x29\x2b-\x2f0-9\x3a\x3d\x3fA-Z\x5fa-z]{0,69}?[^\x2d])--(?:\x0d\x0a(?!--|\x2e|RSET)[^\r\n]*?)*\x0d\x0a--(?P=boundary)\x0d\x0a/R";
    reference:url,www.certego.local/en/news/badepilogue-the-perfect-evasion/;
    classtype:bad-unknown;
    sid:2023255; rev:2;
    metadata:attack_target SMTP_Server, created_at 2016_09_22, deployment Datacenter, performance_impact Low, signature_severity Major, updated_at 2022_03_17;
)

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