CVE-2022-4237 in Welcart e-Commerce Plugin
Summary
by MITRE • 01/03/2023
The Welcart e-Commerce WordPress plugin before 2.8.6 does not validate user input before using it in file_exist() functions via various AJAX actions available to any authenticated users, which could allow users with a role as low as subscriber to perform PHAR deserialisation when they can upload a file and a suitable gadget chain is present on the blog
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 02/21/2025
The CVE-2022-4237 vulnerability affects the Welcart e-Commerce WordPress plugin version 2.8.5 and earlier, presenting a critical security risk that stems from inadequate input validation within the plugin's AJAX handling mechanisms. This flaw specifically targets the file_exist() function calls that occur during various AJAX actions, which are accessible to any authenticated user regardless of their role within the WordPress environment. The vulnerability's severity is amplified by the fact that even users with the lowest possible role of subscriber can exploit this weakness, making it particularly dangerous in environments where user registration is open or where compromised accounts exist. The plugin's failure to validate user-supplied input before passing it to file_exist() functions creates a pathway for malicious actors to manipulate the application's behavior through crafted requests.
The technical exploitation of this vulnerability requires the attacker to first upload a malicious file to the target system, typically through the plugin's file upload functionality. Once the file is uploaded, the attacker can leverage the insecure file_exist() calls to trigger a PHAR deserialization attack, provided that suitable gadget chains are present within the WordPress installation. This process involves the manipulation of serialized PHP objects within a PHAR file, which are then deserialized by the application when the file_exist() function is called with attacker-controlled input. The vulnerability operates under the principle that the application does not properly sanitize or validate the file paths provided by users, allowing arbitrary file system operations to be performed through the AJAX interface. This technique aligns with common web application exploitation patterns where insecure deserialization vulnerabilities are leveraged to achieve remote code execution or privilege escalation within the application context.
The operational impact of CVE-2022-4237 extends beyond simple privilege escalation, as it enables attackers to potentially gain full control over the WordPress installation and underlying server resources. The vulnerability's accessibility to subscriber-level users means that even in environments with strict user access controls, an attacker could exploit this weakness to perform actions that would normally require administrator privileges. The attack surface is particularly concerning because the vulnerability exists within a widely used e-commerce plugin, increasing the potential for widespread exploitation across multiple WordPress installations. The PHAR deserialization aspect of the attack can lead to arbitrary code execution, data exfiltration, or system compromise, depending on the attacker's objectives and the specific gadget chains available within the target environment. This vulnerability directly relates to CWE-20, which describes improper input validation, and can be mapped to ATT&CK technique T1059 for execution through PHP deserialization attacks.
Organizations affected by CVE-2022-4237 should immediately implement the available patch from the plugin vendor, which addresses the input validation issues within the AJAX handling functions. The recommended mitigation strategy includes upgrading to Welcart e-Commerce plugin version 2.8.6 or later, which contains the necessary security fixes to prevent unauthorized file system access through the vulnerable file_exist() function calls. Additionally, administrators should implement network-level restrictions to limit access to the plugin's AJAX endpoints and consider implementing web application firewalls to detect and block malicious requests targeting this vulnerability. Regular security audits of WordPress installations should include verification of plugin versions and assessment of input validation practices within custom and third-party plugins. The vulnerability highlights the critical importance of proper input sanitization and validation within web applications, particularly when handling user-supplied data that may be used in system-level operations such as file system access functions. Security teams should also monitor for indicators of compromise related to PHAR file uploads and unusual file_exist() function calls within their application logs to detect potential exploitation attempts.