ET EXPLOIT Microsoft Exchange Create User Configuration - xbit set 2 (CVE-2021-42321)

alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (
    msg:"ET EXPLOIT Microsoft Exchange Create User Configuration - xbit set 2 (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|CreateUserConfiguration>";
    content:"|3a|UserConfiguration>";
    content:"|3a|BinaryData>";
    base64_decode:offset 0, relative;
    base64_data;
    content:"|00|"; depth:10;
    xbits:isset,ET.2021.42321.1,track ip_src,expire 30;
    xbits:unset,ET.2021.42321.1,track ip_src,expire 30;
    xbits:set,ET.2021.42321.2,track ip_src,expire 30;
    noalert;
    reference:cve,2021-42321;
    classtype:attempted-admin;
    sid:2034520; rev:1;
    metadata:attack_target Server, created_at 2021_11_22, cve CVE_2021_42321, deployment Perimeter, deployment Internal, confidence High, 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;
)