CVE-2007-0109 in WordPress
Summary
by MITRE
wp-login.php in WordPress 2.0.5 and earlier displays different error messages if a user exists or not, which allows remote attackers to obtain sensitive information and facilitates brute force attacks.
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Analysis
by VulDB Data Team • 07/14/2019
The vulnerability identified as CVE-2007-0109 affects WordPress versions 2.0.5 and earlier, specifically within the wp-login.php script that handles user authentication processes. This flaw represents a classic information disclosure issue that significantly weakens the security posture of affected systems. The vulnerability stems from the application's inconsistent error messaging behavior during authentication attempts, where the system provides different responses depending on whether the username exists in the database.
The technical implementation of this vulnerability resides in the authentication logic of WordPress's login handler. When an attacker submits a login request, the wp-login.php script responds with distinct error messages based on the existence of the provided username. If the username does not exist, the system returns one type of error message, whereas if the username exists but the password is incorrect, it returns a different message. This differential response creates a clear indicator for attackers to determine valid usernames, effectively enabling account enumeration attacks. The vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and specifically demonstrates how error handling can inadvertently leak system information.
The operational impact of this vulnerability extends beyond simple information disclosure, as it directly facilitates brute force and credential stuffing attacks. Attackers can systematically test usernames and passwords by first enumerating valid accounts through the inconsistent error responses, then applying automated tools to guess passwords for those identified users. This approach dramatically reduces the computational complexity of successful attacks, as attackers no longer need to guess both valid usernames and passwords simultaneously. The vulnerability creates a significant risk for WordPress installations that rely solely on basic authentication security measures without additional protections such as account lockout mechanisms or rate limiting.
The security implications of CVE-2007-0109 demonstrate how seemingly minor implementation flaws can create substantial attack vectors in web applications. This vulnerability exposes the importance of consistent error handling practices in security-sensitive applications, particularly those managing user authentication. The flaw also highlights the need for proper access control mechanisms and the importance of implementing defensive measures such as account lockout policies, rate limiting, and CAPTCHA systems. Organizations using vulnerable WordPress versions should immediately implement mitigation strategies including disabling user enumeration through configuration changes, implementing robust authentication policies, and upgrading to patched versions of the software. The vulnerability serves as a critical reminder of how error messaging can become a security risk when not properly designed to maintain consistent responses regardless of the underlying authentication state. This issue directly relates to ATT&CK technique T1110, which covers credential access through brute force and password spraying attacks, making it particularly dangerous in environments where automated attack tools are commonly deployed.