CVE-2021-4372 in WooCommerce Dynamic Pricing and Discounts Plugin
Summary
by MITRE • 06/07/2023
The WooCommerce Dynamic Pricing and Discounts plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to, and including, 2.4.1. This is due to missing sanitization on the settings imported via the import() function. This makes it possible for unauthenticated attackers to import a settings file containing malicious JavaScript that would execute when an administrator accesses the settings area of the site.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/05/2023
The WooCommerce Dynamic Pricing and Discounts plugin represents a widely used extension within the WordPress ecosystem that enables merchants to implement complex pricing strategies and discount mechanisms for their online stores. This particular vulnerability affects versions up to and including 241, creating a significant security risk for WordPress sites that rely on this plugin for their e-commerce operations. The flaw exists within the plugin's import functionality, specifically in how it handles settings files that are processed through the import() function, which creates a pathway for malicious actors to inject persistent cross-site scripting payloads into the target system.
The technical implementation of this vulnerability stems from inadequate input validation and sanitization practices within the plugin's codebase. When administrators access the plugin's settings area, the imported configuration data is rendered without proper sanitization, creating a stored XSS vector that allows attackers to execute malicious JavaScript code within the context of the administrator's browser session. This particular weakness aligns with CWE-79, which categorizes cross-site scripting vulnerabilities as a result of insufficient input validation and output encoding. The vulnerability is particularly dangerous because it requires no authentication from the attacker to initiate the malicious payload, making it an attractive target for automated exploitation campaigns.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it provides attackers with the ability to establish persistent access to the administrative interface of affected WordPress sites. Once an administrator loads the malicious settings page, the injected JavaScript code can perform various malicious activities including but not limited to stealing session cookies, redirecting users to malicious sites, modifying store configurations, or even installing additional malware. The stored nature of this vulnerability means that the malicious payload remains active even after the initial import, creating a long-term threat vector that persists until the affected plugin is updated or the malicious settings are manually removed from the system.
From a threat modeling perspective, this vulnerability maps directly to several ATT&CK techniques including T1059.007 for script execution and T1566 for phishing with malicious attachments. The attack surface is particularly concerning because it leverages the trust relationship between administrators and the plugin's import functionality, making it difficult for security personnel to detect malicious activity. Organizations should immediately implement mitigation strategies including updating to the patched version of the plugin, implementing web application firewalls to monitor for suspicious import patterns, and conducting thorough security audits of all installed WordPress plugins. Additionally, network segmentation and privileged access controls should be enforced to limit the potential damage from successful exploitation attempts, while regular security monitoring should be implemented to detect anomalous behavior in the plugin's settings areas.
The vulnerability demonstrates the critical importance of proper input sanitization and validation in web applications, particularly those handling user-provided configuration data. Security practitioners should emphasize the need for comprehensive testing of import/export functionalities and implement automated scanning tools to identify similar vulnerabilities in other plugins and themes. Organizations maintaining WordPress installations should establish robust patch management processes and regularly audit their plugin ecosystems to prevent similar vulnerabilities from being exploited in their environments.