Kimai Open Redirect in SAML Authentication

Executive Summary

Kimai before version 2.53.0 has an open redirect vulnerability in its SAML authentication success handler. This flaw allows attackers with access to the Identity Provider (IdP) to manipulate the RelayState parameter, which is used to redirect users after successful authentication. The system does not validate these RelayState values, enabling attackers to redirect users to malicious websites for credential theft or phishing attacks.

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Detection Guidance

To detect this vulnerability, inspect Kimai instances for versions before 2.53.0. Check SAML authentication success handlers for unvalidated RelayState parameters. Review server logs for unexpected redirects to external domains.

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Impact Analysis

If you use Kimai versions before 2.53.0 with SAML authentication, attackers could trick you into visiting fake login pages or malicious sites after you log in. This could lead to stolen credentials, unauthorized access to your account, or exposure to malware. Users with IdP access could exploit this to target other users.

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Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection principles or HIPAA's security requirements. Organizations may face compliance breaches if user credentials or data are compromised through phishing or credential theft facilitated by this flaw.

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Mitigation Strategies

Upgrade Kimai to version 2.53.0 or later. Validate RelayState parameters in SAML authentication to ensure they only redirect to trusted URLs. Monitor for suspicious redirect patterns in logs.

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