ET EXPLOIT Citrix ADC and NetScaler Gateway Information Disclosure Attempt (CVE-2023-4966)

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/idp/.well-known/openid-configuration"; fast_pattern;
    http.host; bsize:>20000;
    reference:url,www.assetnote.io/resources/research/citrix-bleed-leaking-session-tokens-with-cve-2023-4966;
    reference:cve,2023-4966;
    classtype:attempted-admin;
    sid:2048930; rev:1;
    metadata: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 2023_10_29, 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;
)