huntrule

CVE-2023-4966 Sensitive Info Disclosure Attempt on Citrix ADC via Webserver Logs

Alerts on successful GET requests to the OIDC openid-configuration path that match CVE-2023-4966 related probing patterns.

FreeReviewedSigma · Medium · v5
Category
webserver
Author
Nasreddine Bencherchali (Nextron Systems), Michael Haag (STRT) (SigmaHQ), DRL 1.1
Published
2023-11-28
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Initial Access

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule flags webserver requests that use the GET method to access the OpenID configuration path under /oauth/idp/.well-known/openid-configuration, returning HTTP 200 responses. Such behavior can indicate an attempt to trigger or observe a sensitive information disclosure condition tied to CVE-2023-4966 on Citrix ADC/NetScaler Gateway. Detection relies on webserver telemetry fields for request method, URI stem matching, and the HTTP status code.

Reporting behind it

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Possible Ivanti Pulse Connect Secure Auth Bypass via TOTP Backup Code Path Traversal (via webserver)
Possible Citrix Bleed Session Token Leak via OpenID Configuration Endpoint (CVE-2023-4966) (via webserver)
CVE-2023-4966 Sensitive Info Disclosure Attempt on Citrix ADC via Webserver Logs
Pivot detection · T1190 · 9 related

Changelog

v5
  1. v5
    Candidate ingested via manual entry.2026-07-31
  2. v4
    Candidate ingested via manual entry.2026-07-31
  3. v3
    Candidate ingested via manual entry.2026-07-31
  4. v2
    Candidate ingested via manual entry.2026-07-31
  5. v1
    No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.