alert http any any -> $HOME_NET any (msg:"ET HUNTING Microsoft Exchange OWA Authenticated Unsigned JSON Web Token (JWT) Request M2"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/owa/service.svc|3f|action|3d|getaccesstokenforresource"; fast_pattern; startswith; nocase; http.request_body; content:"tokenrequest|3a 23|exchange"; nocase; pcre:"/^[^\x0d\x0a]*?(?:\x22|\x2522)[rR][eE][sS][oO][uU][rR][sS[eE](?:\x22|\x2522)(?:\x3a|\x253[aA]).*?[hH][tT]{2}[pP]/R"; reference:url,i.blackhat.com/USA-19/Thursday/us-19-Jaiswal-Preventing-Authentication-Bypass-A-Tale-Of-Two-Researchers.pdf; classtype:web-application-activity; sid:2063644; rev:1; metadata:affected_product Microsoft_Exchange, attack_target Server, tls_state TLSDecrypt, created_at 2025_07_21, deployment Perimeter, deployment Internal, confidence Medium, signature_severity Major, tag Exploit, updated_at 2025_07_21, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)