CVE-2009-2431 in WordPress
Summary
by MITRE
WordPress 2.7.1 places the username of a post s author in an HTML comment, which allows remote attackers to obtain sensitive information by reading the HTML source.
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Analysis
by VulDB Data Team • 02/01/2019
The vulnerability identified as CVE-2009-2431 represents a significant information disclosure issue within WordPress version 2.7.1 that exposes user authentication details through improper HTML comment handling. This flaw occurs when WordPress generates HTML output for posts, specifically embedding the author's username within HTML comments that are visible to all users who can access the page source. The vulnerability stems from WordPress's default behavior of including author information in a manner that inadvertently reveals user account details to unauthorized parties.
This technical weakness falls under the category of information disclosure vulnerabilities and can be classified as CWE-200, which specifically addresses information exposure through improper handling of sensitive data. The flaw operates by placing the author's username within HTML comments that are not typically hidden from end users, creating an unintended data leak channel. Attackers can simply view the HTML source of any post page to extract this information, potentially gathering usernames for further exploitation attempts including social engineering, credential stuffing, or targeted attacks against specific user accounts.
The operational impact of this vulnerability extends beyond simple username disclosure, as it provides attackers with foundational information that can be leveraged in more sophisticated attack vectors. When combined with other reconnaissance techniques, the exposed usernames can be used to identify valid user accounts within the WordPress system, potentially enabling credential brute force attacks or targeted phishing campaigns. The vulnerability affects all WordPress installations running version 2.7.1 and earlier, making it particularly concerning given the widespread adoption of this version during its time. This type of information disclosure aligns with techniques described in the MITRE ATT&CK framework under the information gathering phase, where adversaries collect user account information to facilitate subsequent compromise attempts.
The security implications of this vulnerability are particularly severe because it operates at the application layer without requiring authentication or privileged access to exploit. The flaw demonstrates poor input validation and output sanitization practices where WordPress fails to properly separate user authentication data from publicly accessible HTML content. This represents a failure in the principle of least privilege and proper access control implementation, as sensitive user information is exposed through the application's normal operation. Organizations affected by this vulnerability should immediately implement mitigation strategies including updating to patched WordPress versions, implementing proper output filtering, and conducting security audits to identify similar information disclosure vulnerabilities in their web applications. The vulnerability also highlights the importance of regular security updates and the potential consequences of leaving systems unpatched for extended periods.