CVE-2020-36722 in Visual Composer Plugin
Summary
by MITRE • 06/07/2023
The Visual Composer plugin for WordPress is vulnerable to Cross-Site Scripting in versions up to, and including, 26.0 due to insufficient input sanitization and output escaping. This makes it possible for attackers to inject arbitrary web scripts that execute in a victim's browser.
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Analysis
by VulDB Data Team • 07/05/2023
The vulnerability identified as CVE-2020-36722 affects the Visual Composer plugin for WordPress, a widely used page builder tool that allows users to create complex web pages through drag-and-drop interfaces. This particular vulnerability exists in versions up to and including 26.0, representing a significant security risk for WordPress installations that rely on this plugin for content creation and management. The flaw manifests as a cross-site scripting vulnerability that undermines the security model of web applications by enabling attackers to execute malicious scripts in the context of legitimate user sessions.
The technical root cause of this vulnerability stems from inadequate input sanitization and insufficient output escaping mechanisms within the Visual Composer plugin's codebase. When users input data through the plugin's interface, particularly in fields that accept HTML content or dynamic parameters, the plugin fails to properly validate and sanitize this input before processing or storing it. Additionally, the output escaping mechanisms that should protect against XSS attacks are either absent or improperly implemented, allowing malicious scripts to be stored and subsequently executed when legitimate users view pages containing the compromised content. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS attack vector where malicious code persists in the application's database and executes automatically when accessed by other users.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to perform various malicious activities within the context of authenticated users' browsers. An attacker could potentially steal session cookies, redirect users to malicious websites, deface web pages, or even escalate privileges within the WordPress environment. Given that Visual Composer is commonly used by both administrators and regular users, the attack surface is broad, and successful exploitation could compromise entire WordPress installations. The vulnerability particularly affects sites where users have administrative or editor roles, as these users are more likely to interact with the plugin's features and potentially introduce malicious payloads through the vulnerable input fields.
Mitigation strategies for CVE-2020-36722 should prioritize immediate plugin updates to versions that contain proper input validation and output escaping mechanisms. WordPress administrators should also implement additional security measures such as content security policies to limit script execution, regular monitoring of user input through the plugin, and implementing web application firewalls to detect and block suspicious requests. According to ATT&CK framework methodology, this vulnerability aligns with T1059.001 for command and scripting interpreter and T1566.001 for spearphishing attachment, as attackers can use this vulnerability to deliver malicious payloads through compromised WordPress sites. Organizations should also consider implementing least privilege access controls, regular security audits of installed plugins, and maintaining up-to-date security patches as part of their overall defense-in-depth strategy. The vulnerability demonstrates the critical importance of proper input validation and output escaping in web applications, particularly in content management systems where user-generated content processing is prevalent.