ET EXPLOIT Exim New-Line Injection into Spool Header File Inbound M2 (CVE-2020-28021)

Query · suricata

flow:established,to_server;
content:"MAIL|20|FROM";
content:"AUTH="; distance:0;
pcre:"/^[^\+]+(?:\+[A-F0-9]{2}){4,}/R";
content:"+0A"; fast_pattern;
Raw source ET EXPLOIT Exim New-Line Injection into Spool Header File Inbound M2 (CVE-2020-28021) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert smtp any any -> [$HOME_NET,$HTTP_SERVERS,$SMTP_SERVERS] any (
    msg:"ET EXPLOIT Exim New-Line Injection into Spool Header File Inbound M2 (CVE-2020-28021)";
    flow:established,to_server;
    content:"MAIL|20|FROM";
    content:"AUTH="; distance:0;
    pcre:"/^[^\+]+(?:\+[A-F0-9]{2}){4,}/R";
    content:"+0A"; fast_pattern;
    reference:url,www.qualys.com/2021/05/04/21nails/21nails.txt;
    reference:cve,2020-28021;
    classtype:attempted-admin;
    sid:2032901; rev:1;
    metadata:attack_target SMTP_Server, created_at 2021_05_04, cve CVE_2020_28021, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_05_04;
)

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