CVE-2019-11223 in SupportCandy Plugin
Summary
by MITRE
An Unrestricted File Upload Vulnerability in the SupportCandy plugin through 2.0.0 for WordPress allows remote attackers to execute arbitrary code by uploading a file with an executable extension.
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Analysis
by VulDB Data Team • 05/31/2020
The CVE-2019-11223 vulnerability represents a critical unrestricted file upload flaw within the SupportCandy WordPress plugin version 2.0.0 and earlier. This vulnerability stems from inadequate input validation and sanitization mechanisms within the plugin's file upload functionality, creating a pathway for remote attackers to bypass security controls and upload malicious files to the target system. The flaw specifically manifests when the plugin fails to properly validate file extensions or content types, allowing attackers to upload files with executable extensions such as .php, .asp, .jsp, or other potentially harmful formats that can be executed on the web server.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-434, which categorizes unrestricted file upload as a significant security weakness. Attackers can leverage this flaw by crafting malicious files with executable extensions and uploading them through the plugin's interface, potentially gaining remote code execution capabilities on the compromised WordPress installation. The vulnerability operates at the application layer and can be classified under the ATT&CK framework's T1190 technique for exploit public-facing application, where attackers target web applications to gain initial access. This weakness essentially transforms the legitimate file upload feature into a vector for malicious payload delivery, enabling attackers to execute arbitrary code with the privileges of the web server process.
The operational impact of CVE-2019-11223 extends beyond simple code execution, as it can lead to complete system compromise and persistent backdoor access. Once an attacker successfully uploads a malicious file, they can establish a foothold for further exploitation, potentially escalating privileges to gain access to sensitive data, modify website content, or use the compromised system as a launching point for attacks on other systems within the network. The vulnerability affects all WordPress installations running the affected SupportCandy plugin version, making it particularly dangerous as it can be exploited by automated scanning tools that target known vulnerable plugins. Organizations using this plugin face significant risk of data breaches, service disruption, and potential regulatory compliance violations due to the lack of proper access controls and file validation mechanisms.
Mitigation strategies for this vulnerability require immediate patching of the SupportCandy plugin to version 2.0.1 or later, which contains the necessary security fixes. System administrators should implement additional protective measures including restrictive file upload validation that checks both file extensions and content types, implementing proper file naming conventions to prevent executable files from being executed, and configuring web server rules to prevent execution of uploaded files in web-accessible directories. Network segmentation and monitoring solutions should be deployed to detect suspicious upload activities and unauthorized file access attempts. Security best practices such as regular vulnerability scanning, application whitelisting, and maintaining up-to-date security patches form the foundation of defense-in-depth strategies. Organizations should also consider implementing web application firewalls to monitor and filter potentially malicious file upload requests, while ensuring that file upload directories have restricted permissions and are not directly accessible via web requests. The vulnerability underscores the critical importance of proper input validation and the principle of least privilege in web application security, as highlighted by industry standards and frameworks such as the OWASP Top Ten and NIST cybersecurity guidelines.