CVE-2024-7318 is a vulnerability discovered in Keycloak's implementation of OTP (One-Time Password) authentication when used with FreeOTP tokens configured with the default 30-second period. Normally, OTP tokens expire after their designated period, preventing reuse. However, due to this flaw, expired OTP codes remain valid for an additional 30 seconds beyond their intended expiration, effectively doubling the token's validity window to 1 minute. This behavior means that at any given time, two OTP tokens are valid simultaneously, increasing the attack surface and the window of opportunity for attackers to reuse or intercept OTP codes to gain unauthorized access. The vulnerability affects Keycloak versions up to and including 25.0.0. The CVSS 3.1 base score is 4.8 (medium), reflecting the network attack vector with high attack complexity, no privileges required, and no user interaction needed. The impact primarily concerns confidentiality and integrity, as attackers could potentially bypass OTP protections to compromise user accounts. No known exploits have been reported in the wild, but the vulnerability is publicly disclosed and should be addressed proactively. The flaw is rooted in the OTP validation logic and timing checks within Keycloak's authentication flow when interfacing with FreeOTP tokens. This issue highlights the importance of strict adherence to OTP expiration semantics to maintain strong multifactor authentication security.

For European organizations, this vulnerability increases the risk of unauthorized account access through OTP reuse or interception, particularly in sectors relying heavily on Keycloak for identity and access management such as government agencies, financial institutions, and critical infrastructure operators. The extended validity period doubles the window during which an attacker can exploit stolen or intercepted OTP codes, potentially leading to account compromise, data breaches, and unauthorized transactions. While the vulnerability does not directly affect system availability, the compromise of accounts could lead to further lateral movement or privilege escalation within networks. Organizations with high-value targets or sensitive data are at increased risk, especially if they have not implemented additional layers of security such as anomaly detection or adaptive authentication. The medium severity rating reflects a moderate but non-trivial risk that should be addressed promptly to prevent exploitation.

1. Monitor Keycloak vendor advisories and apply patches or updates as soon as a fix for CVE-2024-7318 is released. 2. Temporarily reduce the OTP token validity period if configurable, or adjust FreeOTP settings to minimize token overlap. 3. Implement additional authentication controls such as risk-based or adaptive authentication to detect and block suspicious login attempts. 4. Enhance monitoring and logging of authentication events to identify repeated or anomalous OTP usage patterns. 5. Educate users about the importance of securing their OTP devices and reporting suspicious activity immediately. 6. Consider deploying hardware-based OTP tokens or alternative MFA methods less susceptible to timing issues. 7. Review and tighten session management policies to limit the impact of compromised credentials. 8. Conduct regular security assessments and penetration testing focused on authentication mechanisms to identify related weaknesses.