CVE-2007-4893 in WordPress
Summary
by MITRE
wp-admin/admin-functions.php in Wordpress before 2.2.3 and Wordpress multi-user (MU) before 1.2.5a does not properly verify the unfiltered_html privilege, which allows remote attackers to conduct cross-site scripting (XSS) attacks via modified data to (1) post.php or (2) page.php with a no_filter field.
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Analysis
by VulDB Data Team • 03/15/2021
The vulnerability described in CVE-2007-4893 represents a critical cross-site scripting flaw within the WordPress content management system that affected versions prior to 2.2.3 for standard installations and 1.2.5a for multi-user deployments. This security weakness stems from inadequate privilege verification mechanisms within the administrative functions of WordPress, specifically within the wp-admin/admin-functions.php file. The flaw enables malicious actors to exploit the system by manipulating data through carefully crafted requests to post.php or page.php scripts, leveraging a no_filter field parameter to bypass intended security restrictions.
The technical exploitation of this vulnerability occurs when remote attackers manipulate the unfiltered_html privilege check within WordPress's administrative interface. This privilege is typically restricted to users with elevated permissions such as administrators or editors who are authorized to input raw HTML content. However, the vulnerability allows attackers to bypass this verification process, enabling them to inject malicious JavaScript code through the no_filter parameter. When legitimate users view posts or pages containing this malicious content, the injected scripts execute in their browsers, potentially leading to session hijacking, credential theft, or other malicious activities.
The operational impact of CVE-2007-4893 extends beyond simple XSS attacks, as it represents a fundamental flaw in WordPress's privilege management system that could enable attackers to escalate their privileges within the CMS. This vulnerability specifically aligns with CWE-79, which describes cross-site scripting vulnerabilities, and demonstrates how improper input validation and privilege checks can create persistent security risks. The flaw operates at the application layer and can be exploited without requiring authentication, making it particularly dangerous for WordPress installations that allow user-generated content or have compromised administrator accounts.
This vulnerability directly relates to ATT&CK technique T1566, which covers the exploitation of vulnerabilities in web applications, and specifically addresses the use of web application vulnerabilities for initial access or privilege escalation. The security implications are significant for WordPress installations as it allows attackers to inject malicious content that can persist across multiple user sessions, potentially compromising entire websites and their associated user data. Organizations using vulnerable versions of WordPress face increased risk of data breaches, website defacement, and potential compromise of user credentials through session hijacking techniques.
The recommended mitigation strategies for CVE-2007-4893 involve immediate upgrading to WordPress versions 2.2.3 or later for standard installations and 1.2.5a or later for multi-user deployments. Additionally, administrators should implement proper input sanitization measures and review user privilege assignments to minimize the impact of such vulnerabilities. The fix addresses the core issue by properly validating the unfiltered_html privilege before allowing modification of content through the affected administrative scripts, ensuring that only authorized users can bypass HTML filtering mechanisms. This vulnerability serves as a critical reminder of the importance of proper privilege verification and input sanitization in web application security.