CVE-2016-5835 in WordPress
Summary
by MITRE
WordPress before 4.5.3 allows remote attackers to obtain sensitive revision-history information by leveraging the ability to read a post, related to wp-admin/includes/ajax-actions.php and wp-admin/revision.php.
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Analysis
by VulDB Data Team • 08/24/2022
WordPress versions prior to 4.5.3 contained a critical information disclosure vulnerability that allowed remote attackers to access sensitive revision history data through improperly controlled access permissions. This vulnerability existed within the administrative AJAX actions and revision handling components of the platform, specifically in the wp-admin/includes/ajax-actions.php and wp-admin/revision.php files. The flaw occurred because the system failed to properly validate user permissions when processing revision history requests, enabling unauthorized users to retrieve detailed information about post modifications even when they lacked proper authorization to view such data.
The technical implementation of this vulnerability exploited the lack of proper access control checks within the WordPress administrative interface. When users made requests to retrieve revision history information through the AJAX endpoints, the system did not adequately verify whether the requesting user possessed sufficient privileges to access the specific revision data. This weakness allowed attackers to craft malicious requests that would bypass normal permission controls and expose sensitive metadata about content modifications, including timestamps, author information, and detailed change logs that could reveal internal workflows and content creation patterns.
The operational impact of this vulnerability extended beyond simple information disclosure, as the leaked revision history data could provide attackers with valuable intelligence for planning more sophisticated attacks. The exposed revision information often contained detailed metadata about content creation and editing activities, including timestamps of when changes were made and which users were responsible for modifications. This information could be leveraged to identify potential security weaknesses in user accounts, understand content management workflows, or even discover sensitive information that was inadvertently published through revision history. The vulnerability particularly affected sites where content creators had varying permission levels, as it allowed lower-privileged users to access information that should have been restricted to administrators or editors.
This vulnerability aligns with CWE-284, which addresses improper access control, and represents a classic example of how insufficient authorization checks can lead to information disclosure. From an ATT&CK framework perspective, this issue maps to T1213 - Data from Information Repositories, where adversaries attempt to gather information from content management systems and administrative interfaces. The vulnerability demonstrates how weaknesses in access control mechanisms within web applications can create pathways for attackers to escalate their privileges and gather intelligence about system internals.
The recommended mitigation for this vulnerability involves upgrading to WordPress version 4.5.3 or later, which included proper access control checks in the revision handling components. Administrators should also implement additional monitoring of AJAX endpoints and revision history requests to detect potential exploitation attempts. Security teams should conduct regular audits of user permissions and access controls to ensure that sensitive administrative functionality remains properly restricted. Organizations should also consider implementing web application firewalls and intrusion detection systems that can identify and block suspicious requests to revision and AJAX endpoints that attempt to bypass normal access controls.