ET EXPLOIT Suspected Exim External Auth Overflow (CVE-2023-42115)

Query · suricata

flow:established;
flowbits:isset,ET.eximsmtp;
content:"auth|20|"; nocase; fast_pattern;
pcre:"/^(?:(?:[^A\r\n]+[A])(?:[^A\r\n]+[A])){2,}/R";
target:dest_ip;

Rule dependencies

⚠ Higher-order rule. It fires on other rules' alerts, not on raw events, so it cannot fire on its own. Deploy the rules it depends on too.

Depends on

Raw source ET EXPLOIT Suspected Exim External Auth Overflow (CVE-2023-42115) · 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 any (
    msg:"ET EXPLOIT Suspected Exim External Auth Overflow (CVE-2023-42115)";
    flow:established;
    flowbits:isset,ET.eximsmtp;
    content:"auth|20|"; nocase; fast_pattern;
    pcre:"/^(?:(?:[^A\r\n]+[A])(?:[^A\r\n]+[A])){2,}/R";
    reference:url,www.zerodayinitiative.com/advisories/ZDI-23-1469/;
    reference:url,labs.watchtowr.com/exim-0days-90s-vulns-in-90s-software/;
    reference:cve,2023-42115;
    classtype:attempted-admin;
    sid:2048390; rev:1;
    metadata:attack_target SMTP_Server, created_at 2023_10_03, cve CVE_2023_42115, deployment Perimeter, deployment SSLDecrypt, performance_impact Significant, confidence Low, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_10_03, reviewed_at 2023_10_03;
    target:dest_ip;
)

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