CVE-2021-25119 in AGIL Plugin
Summary
by MITRE • 05/16/2022
The AGIL WordPress plugin through 1.0 accepts all zip files and automatically extracts the zip file without validating the extracted file type. Allowing high privilege users such as admin to upload an arbitrary file like PHP, leading to RCE
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Analysis
by VulDB Data Team • 05/18/2022
The CVE-2021-25119 vulnerability resides within the AGIL WordPress plugin version 1.0 and represents a critical security flaw that enables unauthorized remote code execution through improper file validation mechanisms. This vulnerability specifically targets the plugin's handling of zip file uploads, where the system fails to implement adequate validation checks on the contents of extracted archives. The flaw allows attackers with administrative privileges to upload malicious zip files containing arbitrary file types including PHP scripts, which are then automatically extracted and executed within the WordPress environment. The vulnerability demonstrates a fundamental failure in input validation and file type checking that directly violates established security principles for web application development.
The technical implementation of this vulnerability stems from the plugin's lack of proper sanitization and validation processes during the zip file extraction phase. When administrators upload zip archives through the plugin's interface, the system automatically extracts all contained files without performing type verification or security checks on the extracted content. This behavior creates an arbitrary file upload condition that can be exploited by malicious actors with administrative access levels. The vulnerability is particularly dangerous because it leverages the existing administrative privileges of legitimate users, making detection more difficult while providing direct access to execute arbitrary code on the target system. This flaw aligns with CWE-434 which describes insecure file upload vulnerabilities where applications accept files without proper validation of their contents or type.
The operational impact of CVE-2021-25119 extends far beyond simple privilege escalation, as it provides attackers with complete control over the affected WordPress installation. Once an attacker successfully uploads and extracts a malicious PHP file, they can execute arbitrary commands on the server, potentially leading to data exfiltration, system compromise, or further network infiltration. The vulnerability can be exploited to establish persistent backdoors, modify website content, steal sensitive information, or use the compromised system as a launching point for attacks against other network resources. From an attacker's perspective, this vulnerability operates under the ATT&CK framework's T1059.007 technique for command and script injection, specifically targeting web shell execution through file upload mechanisms. The ease of exploitation and the high privileges required for successful implementation make this vulnerability particularly attractive to threat actors seeking to maintain persistent access to WordPress environments.
Mitigation strategies for CVE-2021-25119 must address both immediate remediation and long-term security improvements. The most effective immediate solution involves updating to the latest version of the AGIL plugin where the vulnerability has been patched, as the developers have implemented proper file type validation and extraction controls. Organizations should also implement network-based restrictions on zip file uploads, particularly for administrative accounts, and establish strict file type whitelisting policies for all uploaded content. Additionally, security monitoring should be enhanced to detect unusual file extraction patterns and unauthorized administrative activities. The vulnerability highlights the importance of following secure coding practices such as those outlined in the OWASP Top Ten, specifically addressing the prevention of insecure file uploads and ensuring proper input validation. Regular security audits and penetration testing should be conducted to identify similar validation flaws in other plugins and themes, while implementing principle of least privilege access controls to minimize the potential impact of compromised administrative accounts.