CVE-2024-11208 Overview
CVE-2024-11208 affects Apereo Central Authentication Service (CAS) version 6.6 and concerns improper session handling in the /login?service endpoint. The flaw is classified under [CWE-613: Insufficient Session Expiration], allowing remote attackers to manipulate session expiration behavior under specific conditions.
The exploit has been disclosed publicly through a third-party gist, but the vendor did not respond to disclosure attempts. Attack complexity is high, which limits practical exploitation. No active exploitation has been reported, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog.
Critical Impact
Remote attackers can leverage insufficient session expiration in Apereo CAS 6.6 to interact with sessions that should have terminated, potentially affecting authentication assurance for downstream services.
Affected Products
- Apereo Central Authentication Service 6.6.0
- Deployments exposing the /login?service endpoint over the network
- Single Sign-On (SSO) integrations relying on CAS 6.6 session lifecycle
Discovery Timeline
- 2024-11-14 - CVE-2024-11208 published to NVD
- 2024-11-19 - Last updated in NVD database
Technical Details for CVE-2024-11208
Vulnerability Analysis
The vulnerability resides in an unspecified function reachable via the /login?service endpoint of Apereo CAS 6.6. An attacker can manipulate request parameters in a way that affects session expiration handling.
This maps to [CWE-613: Insufficient Session Expiration]. When session expiration is not enforced consistently, an attacker may continue to use or interact with a session that should have been invalidated.
The attack requires no authentication and no user interaction, but the complexity is high. Public reporting describes the exploit as difficult to reproduce reliably. The EPSS probability is 0.741%, placing it in the 49th percentile for likelihood of exploitation activity.
Root Cause
The root cause is improper handling of session lifecycle state within the CAS login flow. CAS does not consistently terminate or invalidate session artifacts associated with the service parameter once expiration conditions should apply.
Because Apereo CAS brokers authentication for downstream applications, weakened session expiration affects the trust model that relying parties place on CAS tickets and SSO sessions.
Attack Vector
The attack vector is network-based against the CAS login endpoint. An unauthenticated remote attacker submits crafted requests to /login?service and manipulates fields that influence session expiration logic.
A proof-of-concept reference is hosted on a public gist by 0xArthurSouza and tracked in VulDB entry 284522. Successful exploitation requires meeting specific timing and state conditions, which accounts for the high attack complexity rating.
No verified exploitation code is reproduced here. Refer to the VulDB entry 284522 and the public PoC gist for technical reproduction details.
Detection Methods for CVE-2024-11208
Indicators of Compromise
- Repeated unauthenticated requests to /login?service from the same source with varying parameters
- Authentication events that succeed using session identifiers older than the configured sessionTimeout
- CAS ticket validation events for sessions that should have been expired
- HTTP requests with unusual service parameter values targeting CAS 6.6 instances
Detection Strategies
- Inspect CAS application logs for anomalies in TGT (Ticket Granting Ticket) lifecycle events, especially reuse after expected expiration
- Correlate authentication assertions issued to downstream services against expected session timeouts
- Deploy web application firewall (WAF) rules to flag malformed or repetitive requests to the /login?service endpoint
- Baseline normal CAS authentication flows and alert on sessions that exceed configured lifetime thresholds
Monitoring Recommendations
- Enable verbose audit logging in cas.properties for ticket creation, validation, and expiration events
- Forward CAS logs to a centralized SIEM with retention sufficient to investigate slow-moving session anomalies
- Monitor outbound SSO assertions to relying parties for sessions older than policy permits
- Track HTTP 200 responses on /login?service paired with reused session cookies across IP changes
How to Mitigate CVE-2024-11208
Immediate Actions Required
- Inventory all Apereo CAS deployments and confirm whether any instance runs version 6.6.0
- Restrict network access to the CAS login endpoint to trusted networks or via reverse proxy controls where feasible
- Reduce configured session and ticket lifetimes to limit the window in which expiration weaknesses can be abused
- Force re-authentication for high-value relying services until a vendor fix is available
Patch Information
The vendor did not respond to disclosure attempts, and no official patch reference is published in the advisory data. Administrators should monitor the Apereo CAS project repository and release notes for fixes addressing session expiration handling, and plan an upgrade path away from the 6.6 branch.
Workarounds
- Lower cas.ticket.tgt.primary.max-time-to-live-in-seconds and related ticket expiration settings to minimize session reuse windows
- Enforce shorter idle timeouts at the reverse proxy or load balancer layer in front of CAS
- Require step-up authentication or multi-factor authentication (MFA) for sensitive services brokered by CAS
- Disable persistent SSO cookies where session continuity is not a business requirement
# Example CAS session hardening in cas.properties
cas.ticket.tgt.primary.max-time-to-live-in-seconds=3600
cas.ticket.tgt.primary.time-to-kill-in-seconds=900
cas.ticket.st.time-to-kill-in-seconds=10
cas.sso.create-sso-cookie-on-renew-authn=false
cas.sso.renew-authn-enabled=true
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
