CVE-2021-4338 in 404 to 301 Plugin
Summary
by MITRE • 06/07/2023
The 404 to 301 plugin for WordPress is vulnerable to authorization bypass due to missing capability checks on the open_redirect & save_redirect functions in versions up to, and including, 3.0.7. This makes it possible for authenticated attackers to view, create and edit redirections.
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Analysis
by VulDB Data Team • 07/05/2023
The CVE-2021-4338 vulnerability affects the 404 to 301 WordPress plugin, which is designed to handle URL redirections for websites. This plugin serves as a critical component in maintaining website navigation and SEO performance by automatically redirecting users from non-existent pages to relevant content. The vulnerability stems from inadequate access control mechanisms within the plugin's core functionality, specifically in the open_redirect and save_redirect functions. These functions are responsible for managing the creation and modification of URL redirection rules that govern how a website handles requests for missing or changed content.
The technical flaw manifests as a missing capability check that should validate user permissions before allowing administrative operations. When authenticated attackers exploit this vulnerability, they can bypass the standard WordPress authorization mechanisms that normally restrict access to plugin settings and redirection management features. This authorization bypass occurs because the plugin fails to verify whether the currently logged-in user possesses the necessary capabilities such as 'manage_options' or equivalent administrative privileges required to modify redirection rules. The vulnerability exists in plugin versions up to and including 3.0.7, indicating that developers did not implement proper input validation or capability verification before executing sensitive operations.
The operational impact of this vulnerability is significant for WordPress website administrators and security teams. Attackers who can authenticate to the WordPress system gain unauthorized access to redirection management capabilities, potentially allowing them to redirect visitors to malicious websites, steal user credentials through phishing redirections, or manipulate website traffic for malicious purposes. This vulnerability undermines the integrity of website navigation systems and can be exploited to create persistent redirection chains that may go unnoticed for extended periods. The ability to create and edit redirections provides attackers with a persistent backdoor mechanism that can be used for ongoing malicious activities without requiring additional authentication steps.
The vulnerability aligns with CWE-285, which addresses improper authorization issues in software systems, and can be mapped to ATT&CK technique T1078.004 for Valid Accounts, where attackers leverage legitimate credentials to perform unauthorized actions. Organizations using vulnerable versions of this plugin face increased risk of data breaches, reputation damage, and potential compliance violations. The exploitation of this vulnerability demonstrates a common security pattern where plugins fail to implement proper access controls despite handling sensitive administrative functions. Security practitioners should note that this vulnerability affects not just the immediate plugin functionality but also represents a broader concern about plugin security practices in the WordPress ecosystem.
Mitigation strategies should include immediate updating of the 404 to 301 plugin to version 3.0.8 or later, which contains the necessary capability checks and authorization controls. Administrators should also implement regular security audits of installed plugins, ensuring that all third-party components are kept current with security patches. Network monitoring should be enhanced to detect unusual redirection patterns that might indicate exploitation attempts. Additionally, implementing role-based access controls and limiting plugin permissions to the minimum required privileges can reduce the potential impact of similar vulnerabilities. Organizations should establish comprehensive patch management procedures that include automated vulnerability scanning and immediate remediation of identified security flaws. The incident underscores the importance of proper input validation and capability verification in plugin development, particularly for components that handle website navigation and user traffic management functions.