CVE-2002-2028 in Windows
Summary
by MITRE
The screensaver on Windows NT 4.0, 2000, XP, and 2002 does not verify if a domain account has already been locked when a valid password is provided, which makes it easier for users with physical access to conduct brute force password guessing.
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Analysis
by VulDB Data Team • 04/07/2017
The vulnerability described in CVE-2002-2028 represents a significant security flaw in the Windows operating system authentication mechanism, specifically affecting Windows NT 4.0, 2000, XP, and 2002 platforms. This issue stems from the screensaver implementation's failure to properly validate account lockout status during authentication attempts, creating an exploitable condition that undermines the system's password protection mechanisms. The flaw particularly impacts environments where physical access to systems is possible, as it removes a critical layer of security that would normally prevent repeated authentication attempts against locked accounts.
The technical implementation of this vulnerability lies in the screensaver's authentication process which operates independently of the standard account lockout validation procedures. When a user attempts to unlock a protected screen saver with a valid password, the system should verify whether the account has been locked due to multiple failed authentication attempts. However, the screensaver component bypasses this crucial verification step, allowing attackers to continue attempting password guesses even when accounts have been locked by previous failed attempts. This behavior creates a window of opportunity for brute force attacks, as the authentication system fails to enforce the account lockout policies that are normally enforced during regular login processes. The vulnerability specifically relates to the improper handling of authentication state within the graphical user interface components, which should maintain consistency with the underlying security policies.
From an operational perspective, this vulnerability significantly weakens the security posture of affected systems by enabling unauthorized access through physical proximity attacks. Attackers with physical access can exploit this flaw to conduct repeated password guessing attempts without triggering the normal account lockout mechanisms that would typically protect against such attacks. The impact extends beyond simple password guessing as it effectively neutralizes the account lockout feature, which is a fundamental security control designed to prevent automated brute force attacks. This vulnerability particularly affects enterprise environments where desktop systems are accessible to unauthorized individuals, as it removes the protection that should prevent attackers from systematically working through password lists against locked accounts. The operational risk is compounded by the fact that the screensaver authentication process is often used as a convenience feature, making it more likely to be triggered during security-sensitive periods when physical access might be unmonitored.
The mitigation strategies for this vulnerability must address both the immediate security gap and the underlying design flaw in the authentication process. System administrators should implement additional account lockout policies that specifically address screen saver authentication attempts, ensuring that failed attempts during screensaver unlocking trigger the appropriate account lockout mechanisms. Network security controls should be enhanced to monitor for unusual authentication patterns, including repeated failed attempts against the same accounts during screensaver unlock operations. The implementation of additional physical security measures, such as secure workstations and restricted access to systems, becomes crucial in environments where this vulnerability cannot be immediately remediated through software patches. Organizations should also consider implementing stronger authentication mechanisms, such as smart cards or biometric authentication, to reduce reliance on password-based systems that are vulnerable to this type of attack. This vulnerability aligns with CWE-617, which addresses the weakness of reachable assertion, and maps to ATT&CK technique T1110.003 for Brute Force: Password Guessing, highlighting the specific attack vector that this vulnerability enables.