ET EXPLOIT Suspected Exim External Auth Overflow (CVE-2023-4115) set

alert smtp $HOME_NET any -> any any (
    msg:"ET EXPLOIT Suspected Exim External Auth Overflow (CVE-2023-4115) set";
    flow:established;
    flowbits:set,ET.eximsmtp;
    flowbits:noalert;
    content:"ESMTP Exim|20|"; fast_pattern;
    reference:url,www.zerodayinitiative.com/advisories/ZDI-23-1469/;
    reference:url,labs.watchtowr.com/exim-0days-90s-vulns-in-90s-software/;
    reference:cve,2023-4115;
    classtype:attempted-admin;
    sid:2048389; rev:1;
    metadata:attack_target SMTP_Server, created_at 2023_10_03, cve CVE_2023_4115, 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:src_ip;
)