CVE-2024-41107: Apache CloudStack Auth Bypass Vulnerability

CVE-2024-41107 Overview

CVE-2024-41107 is an Authentication Bypass vulnerability affecting Apache CloudStack's SAML authentication mechanism. The CloudStack SAML authentication (disabled by default) does not enforce signature check, allowing attackers to bypass authentication by submitting spoofed SAML responses. In CloudStack environments where SAML authentication is enabled, an attacker that initiates CloudStack SAML single sign-on authentication can bypass SAML authentication by submitting a spoofed SAML response with no signature and known or guessed username and other user details of a SAML-enabled CloudStack user-account.

Critical Impact

Complete compromise of resources owned and/or accessible by SAML-enabled user accounts in affected CloudStack environments where SAML authentication is enabled.

Affected Products

• Apache CloudStack versions prior to 4.18.2.2
• Apache CloudStack versions prior to 4.19.1.0
• Any CloudStack deployment with SAML authentication enabled (saml2.enabled set to true)

Discovery Timeline

• 2024-07-19 - CVE-2024-41107 published to NVD
• 2025-03-19 - Last updated in NVD database

Technical Details for CVE-2024-41107

Vulnerability Analysis

This vulnerability stems from a fundamental flaw in how Apache CloudStack handles SAML authentication responses. The SAML authentication plugin fails to enforce cryptographic signature validation on incoming SAML responses, which is a critical security control in any SAML-based single sign-on implementation. SAML signatures serve as the primary mechanism to ensure that authentication assertions originate from a trusted Identity Provider (IdP) and have not been tampered with in transit.

Without signature enforcement, an attacker can craft arbitrary SAML responses containing forged assertions. If the attacker possesses knowledge of—or can successfully guess—a valid username and associated user details for a SAML-enabled account, they can construct a spoofed SAML response that CloudStack will accept as legitimate, granting unauthorized access to that user's account and all associated cloud resources.

Root Cause

The root cause is classified as CWE-290: Authentication Bypass by Spoofing. The CloudStack SAML authentication implementation does not properly verify the cryptographic signature on SAML assertions before accepting them as valid authentication proofs. This missing validation step allows attackers to forge authentication responses that the system trusts implicitly.

Attack Vector

The attack is network-based and requires the attacker to initiate a SAML single sign-on flow against a vulnerable CloudStack instance. The attack involves intercepting or replacing the SAML response in the authentication flow with a crafted unsigned response containing the target user's identity attributes.

The exploitation process involves:

1. The attacker initiates a SAML SSO authentication request to CloudStack
2. Instead of forwarding to the legitimate IdP, the attacker crafts a spoofed SAML response
3. The spoofed response contains no signature but includes known or guessed user details
4. CloudStack accepts the unsigned response due to missing signature validation
5. The attacker gains access to the targeted user account and associated cloud resources

For detailed technical information, refer to the Apache CloudStack Security Advisory and GitHub CloudStack Issue #4519.

Detection Methods for CVE-2024-41107

Indicators of Compromise

• SAML authentication requests or responses lacking valid cryptographic signatures
• Unusual login patterns for SAML-enabled user accounts, especially from unexpected IP addresses
• Authentication events without corresponding IdP-side login records
• Multiple successful authentications for the same user from disparate geographic locations

Detection Strategies

• Monitor SAML authentication logs for responses that do not contain signature elements
• Implement alerting on authentication attempts that bypass normal IdP authentication flows
• Cross-reference CloudStack authentication logs with IdP authentication logs to identify discrepancies
• Deploy network monitoring to detect anomalous SAML traffic patterns

Monitoring Recommendations

• Enable verbose logging for SAML authentication events in CloudStack
• Implement centralized log aggregation for correlation analysis across CloudStack and IdP systems
• Configure alerts for authentication events from SAML-enabled accounts that lack corresponding IdP audit trails
• Monitor for changes to the saml2.enabled configuration setting

How to Mitigate CVE-2024-41107

Immediate Actions Required

• Disable SAML authentication by setting the saml2.enabled global setting to false if SAML is not required
• Audit all SAML-enabled user accounts for signs of unauthorized access
• Review recent authentication logs for suspicious activity
• Upgrade to Apache CloudStack version 4.18.2.2, 4.19.1.0, or later

Patch Information

Apache has released patched versions that address this vulnerability. Organizations should upgrade to version 4.18.2.2 for the 4.18.x branch or version 4.19.1.0 for the 4.19.x branch. Detailed patch information is available in the Apache CloudStack Security Advisory and the Apache Mailing List Thread.

Workarounds

• Disable SAML authentication entirely by setting saml2.enabled to false in the global configuration
• Implement network-level access controls to restrict SAML authentication endpoints to trusted networks
• Enable additional authentication factors for SAML-enabled accounts as a compensating control
• Monitor and audit SAML-enabled accounts with increased scrutiny until patches can be applied

# Disable SAML authentication in CloudStack
# Access CloudStack management server and update global settings
cloudmonkey set saml2.enabled false

# Verify the setting has been applied
cloudmonkey list configurations name=saml2.enabled