CVE-2020-36709 in KingComposer Plugin
Summary
by MITRE • 06/07/2023
The Page Builder: KingComposer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via via shortcode in versions before 2.9.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 07/05/2023
The vulnerability identified as CVE-2020-36709 affects the Page Builder: KingComposer plugin for WordPress, specifically impacting versions prior to 2.9.4. This represents a critical security flaw that undermines the integrity of WordPress installations relying on this plugin for content creation and page building functionalities. The vulnerability exists within the plugin's handling of shortcode parameters, creating an avenue for malicious actors to exploit the system through stored cross-site scripting techniques that persist across user sessions.
The technical flaw stems from insufficient input sanitization and inadequate output escaping mechanisms within the plugin's shortcode processing functionality. When administrators or users with appropriate privileges create or modify content using KingComposer's page builder interface, the plugin fails to properly validate and sanitize user-supplied input before storing it in the database. This allows attackers to inject malicious JavaScript code through shortcode parameters that are then stored and executed whenever legitimate users access pages containing the compromised content. The vulnerability operates as a stored XSS attack because the malicious code is permanently saved in the database rather than being reflected in a single request.
The operational impact of this vulnerability is significant for WordPress administrators and end users who rely on KingComposer for website content management. Authenticated attackers with privileges to create or edit pages can inject persistent malicious scripts that execute in the context of other users' browsers when they access compromised pages. This creates a potential attack surface where attackers can steal session cookies, perform unauthorized actions on behalf of users, redirect users to malicious sites, or even escalate privileges within the WordPress environment. The vulnerability particularly affects sites where multiple administrators or users with editing capabilities exist, as any of these users could potentially exploit the flaw.
Mitigation strategies for CVE-2020-36709 should prioritize immediate plugin updates to version 2.9.4 or later, which contain the necessary patches addressing the input sanitization and output escaping deficiencies. System administrators should also implement additional security measures including role-based access controls to limit who can create or modify content, regular security audits of plugin installations, and monitoring for suspicious activity in content management areas. Organizations should consider implementing content security policies and web application firewalls to provide additional defense layers. This vulnerability aligns with CWE-79 which categorizes cross-site scripting flaws, and maps to ATT&CK technique T1546.001 for registry run keys and startup folder, though the specific execution vector here involves stored payload injection within the WordPress content management system rather than traditional persistence mechanisms.