Rule History

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;)