ET EXPLOIT Possible Microsoft Exchange Server Remote Code Execution Inbound (CVE-2021-42321)

Query · suricata

flow:established,to_server;
http.method;
content:"POST";
http.uri;
content:"/ews/exchange.asmx"; fast_pattern;
http.request_body;
content:"<?xml";
content:"<soap|3a|Body>";
content:"|3a|GetClientAccessToken>";
content:"|3a|TokenRequests>";
xbits:isset,ET.2021.42321.2,track ip_src,expire 30;
xbits:unset,ET.2021.42321.2,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

Raw source ET EXPLOIT Possible Microsoft Exchange Server Remote Code Execution Inbound (CVE-2021-42321) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (
    msg:"ET EXPLOIT Possible Microsoft Exchange Server Remote Code Execution Inbound (CVE-2021-42321)";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:"/ews/exchange.asmx"; fast_pattern;
    http.request_body;
    content:"<?xml";
    content:"<soap|3a|Body>";
    content:"|3a|GetClientAccessToken>";
    content:"|3a|TokenRequests>";
    xbits:isset,ET.2021.42321.2,track ip_src,expire 30;
    xbits:unset,ET.2021.42321.2,track ip_src,expire 30;
    reference:cve,2021-42321;
    classtype:attempted-admin;
    sid:2034521; rev:1;
    metadata:attack_target Server, created_at 2021_11_22, cve CVE_2021_42321, deployment Perimeter, deployment Internal, confidence Medium, signature_severity Major, tag Exploit, tag CISA_KEV, updated_at 2021_11_22, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
)

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