CVE-2020-36747 in Lightweight Sidebar Manager Plugin
Summary
by MITRE • 07/01/2023
The Lightweight Sidebar Manager plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 1.1.4. This is due to missing or incorrect nonce validation on the metabox_save() function. This makes it possible for unauthenticated attackers to save metbox data via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
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Analysis
by VulDB Data Team • 07/01/2023
The Lightweight Sidebar Manager plugin for WordPress represents a common category of web application vulnerabilities that exploits fundamental security mechanisms designed to prevent unauthorized actions. This particular vulnerability affects versions up to and including 1.1.4, making it a significant concern for WordPress site administrators who have not updated their installations. The vulnerability stems from a critical flaw in the plugin's implementation of cross-site request forgery protection mechanisms, which are essential for maintaining the integrity of user sessions and preventing malicious exploitation. The issue specifically manifests in the metabox_save() function where the necessary security validation has been omitted or incorrectly implemented, creating an exploitable condition that undermines the security model of the WordPress platform.
The technical flaw in this vulnerability can be categorized under CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses in software applications. The absence of proper nonce validation in the metabox_save() function creates a scenario where an attacker can craft malicious requests that appear legitimate to the WordPress system. A nonce is a cryptographic value that is used once and only once to ensure that requests are genuine and not forged by malicious actors. When this validation mechanism fails, the system cannot distinguish between legitimate requests initiated by authorized users and malicious requests crafted by attackers. This vulnerability enables attackers to manipulate sidebar configurations and potentially gain unauthorized access to administrative functions through the manipulation of WordPress metabox data structures. The flaw is particularly dangerous because it requires no authentication to exploit, meaning that attackers can operate entirely in the realm of unauthenticated access while still achieving significant system compromise.
The operational impact of this vulnerability extends beyond simple data manipulation to encompass potential system compromise and administrative access escalation. An attacker who successfully exploits this vulnerability can modify sidebar configurations, potentially redirecting users to malicious websites or injecting harmful content into the site's interface. The attack vector relies on social engineering techniques where administrators are tricked into clicking malicious links or visiting compromised websites that trigger the forged requests. This makes the vulnerability particularly insidious because it leverages human factors alongside technical weaknesses. The consequences could include unauthorized modification of site content, potential data exfiltration through manipulated sidebar widgets, and the establishment of persistent backdoors through sidebar configuration changes that might be overlooked during routine security audits.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security hardening measures. The most critical immediate action is to upgrade the Lightweight Sidebar Manager plugin to a version that properly implements nonce validation in the metabox_save() function, which would align with the principle of least privilege and proper input validation. Administrators should also implement additional security layers including regular plugin updates, monitoring for unauthorized configuration changes, and maintaining comprehensive backup systems that can quickly restore affected sites. The vulnerability demonstrates the importance of implementing proper security controls such as the Content Security Policy headers and regular security audits of installed plugins. Organizations should also consider implementing web application firewalls to detect and block suspicious requests that attempt to exploit known CSRF vulnerabilities, as well as establishing security awareness training for administrators to recognize social engineering attempts that could exploit this weakness. The remediation process should include verification that all sidebar configurations have not been tampered with and that no unauthorized modifications have been made to the WordPress installation.