ET HUNTING Microsoft Exchange OWA Authenticated Unsigned JSON Web Token (JWT) Request M2

Query · suricata

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";
target:dest_ip;
Raw source ET HUNTING Microsoft Exchange OWA Authenticated Unsigned JSON Web Token (JWT) Request M2 · 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 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;
)

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