CVE-2016-5832 in WordPress
Summary
by MITRE
The customizer in WordPress before 4.5.3 allows remote attackers to bypass intended redirection restrictions via unspecified vectors.
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Analysis
by VulDB Data Team • 05/08/2019
The vulnerability identified as CVE-2016-5832 represents a critical access control flaw within WordPress core software that affects versions prior to 4.5.3. This issue specifically targets the customizer functionality, which serves as a powerful interface allowing users to modify various aspects of their WordPress site including themes, widgets, and navigation menus. The customizer operates as a sophisticated administrative tool that provides real-time preview capabilities and seamless integration with the site's existing configuration. The vulnerability stems from insufficient validation mechanisms within the redirection logic that governs how users are directed when accessing customizer features. Attackers can exploit this weakness to manipulate the redirection behavior and gain unauthorized access to restricted administrative functions that should only be available to authenticated users with appropriate privileges. This flaw essentially undermines the fundamental security model of WordPress by allowing unauthenticated or improperly authenticated users to bypass intended access controls and potentially execute malicious actions within the administrative interface.
The technical implementation of this vulnerability involves the customizer's handling of URL parameters and session management during the redirection process. When users attempt to access the customizer, the system should verify user authentication status and authorization levels before permitting access to specific administrative functions. However, the flaw allows attackers to manipulate the redirection vectors through unspecified input parameters that control the flow of user navigation within the customizer environment. This manipulation can occur through crafted HTTP requests that exploit the lack of proper input sanitization and validation. The vulnerability's impact extends beyond simple access bypass, as it can potentially enable attackers to perform actions such as modifying theme settings, accessing sensitive configuration data, or even executing arbitrary code within the context of the WordPress installation. The unspecified vectors mentioned in the description suggest that multiple attack surfaces may be affected, including but not limited to URL rewriting, parameter injection, or session manipulation techniques that could be leveraged to achieve unauthorized access.
From an operational perspective, this vulnerability poses significant risks to WordPress installations that have not been updated to version 4.5.3 or later. Organizations relying on older WordPress versions face potential compromise of their entire content management system, as the customizer bypass allows attackers to access administrative functions without proper authentication. The implications are particularly severe for sites with multiple administrators or those that rely heavily on customizer features for site management. Attackers could potentially exploit this vulnerability to modify site content, install malicious plugins, change user permissions, or even establish persistent backdoors within the WordPress environment. The attack surface is further expanded by the fact that the customizer is often used by non-technical users who may not be aware of the security implications of accessing administrative interfaces. This vulnerability also represents a significant concern for managed service providers and hosting companies that maintain multiple WordPress installations, as a single compromised site could potentially serve as a foothold for broader attacks within their infrastructure. The vulnerability's classification aligns with CWE-284 Access Control Issues, specifically focusing on improper access control mechanisms that allow unauthorized access to protected resources.
The mitigation strategy for CVE-2016-5832 centers exclusively on updating WordPress installations to version 4.5.3 or later, which contains the necessary patches to address the customizer redirection bypass vulnerability. Organizations should prioritize immediate deployment of this security update across all affected WordPress installations to eliminate the risk of exploitation. Additionally, system administrators should implement comprehensive monitoring of access logs to detect any suspicious activity related to customizer access attempts or unusual redirection patterns that might indicate exploitation attempts. Security hardening measures should include implementing proper network segmentation to limit access to WordPress administrative interfaces and deploying web application firewalls that can detect and block malicious requests targeting the customizer functionality. The vulnerability's remediation also emphasizes the importance of maintaining current security practices and regular software updates as part of a comprehensive cybersecurity strategy. Organizations should also consider implementing multi-factor authentication for administrative accounts and establishing robust backup procedures to ensure quick recovery in case of successful exploitation attempts. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the T1068 privilege escalation sub-technique related to local or remote access to administrative interfaces, highlighting the critical nature of addressing such access control weaknesses in content management systems.