ET EXPLOIT Microsoft Exchange - Successful msExchEcpCanary Disclosure (CVE-2021-33766)

Query · suricata

flow:established,from_server;
http.stat_code;
content:"500";
http.cookie;
content:"msExchEcpCanary="; fast_pattern;
flowbits:isset,ET.proxytoken;
flowbits:unset,ET.proxytoken;
xbits:set,ET.proxytoken.500,track ip_src,expire 30;

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

Feeds into

  • 1 rule read ET.proxytoken.500 · view all
Raw source ET EXPLOIT Microsoft Exchange - Successful msExchEcpCanary Disclosure (CVE-2021-33766) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http [$HOME_NET,$HTTP_SERVERS] any -> any any (
    msg:"ET EXPLOIT Microsoft Exchange - Successful msExchEcpCanary Disclosure (CVE-2021-33766)";
    flow:established,from_server;
    http.stat_code;
    content:"500";
    http.cookie;
    content:"msExchEcpCanary="; fast_pattern;
    flowbits:isset,ET.proxytoken;
    flowbits:unset,ET.proxytoken;
    xbits:set,ET.proxytoken.500,track ip_src,expire 30;
    reference:cve,2021-33766;
    classtype:attempted-admin;
    sid:2033835; rev:2;
    metadata:created_at 2021_08_30, cve CVE_2021_33766, confidence High, signature_severity Major, tag CISA_KEV, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_30;
)

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