alert http $EXTERNAL_NET any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET EXPLOIT Citrix ADC and NetScaler Gateway Information Disclosure Attempt (CVE-2023-4966)"; flow:established,to_server; flowbits:set,ET.CVE-2023-4966.LeakAttempt; http.uri; content:"/oauth/rp/.well-known/openid-configuration"; fast_pattern; http.host; bsize:>2000; reference:url,www.assetnote.io/resources/research/citrix-bleed-leaking-session-tokens-with-cve-2023-4966; reference:cve,2023-4966; classtype:attempted-admin; sid:2048931; rev:2; metadata:affected_product Citrix, attack_target Web_Server, created_at 2023_10_29, cve CVE_2023_4966, deployment Perimeter, deployment SSLDecrypt, performance_impact Low, confidence High, signature_severity Major, tag CISA_KEV, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_01_31, reviewed_at 2023_10_29, mitre_tactic_id TA0007, mitre_tactic_name Discovery, mitre_technique_id T1082, mitre_technique_name System_Information_Discovery; target:dest_ip;)