CVE-2020-25213 in File Manager Plugin
Summary
by MITRE
The File Manager (wp-file-manager) plugin before 6.9 for WordPress allows remote attackers to upload and execute arbitrary PHP code because it renames an unsafe example elFinder connector file to have the .php extension. This, for example, allows attackers to run the elFinder upload (or mkfile and put) command to write PHP code into the wp-content/plugins/wp-file-manager/lib/files/ directory. This was exploited in the wild in August and September 2020.
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Analysis
by VulDB Data Team • 03/09/2025
The vulnerability identified as CVE-2020-25213 affects the WordPress File Manager plugin version 6.8 and earlier, representing a critical security flaw that enables remote code execution through improper file handling mechanisms. This vulnerability stems from the plugin's inadequate sanitization of file uploads, specifically concerning how it processes the elFinder connector file. The flaw allows attackers to exploit a rename operation that converts an unsafe example file into a PHP executable, creating a persistent backdoor within the WordPress installation. The vulnerability operates through a well-documented attack pattern that aligns with CWE-434, which describes the improper restriction of uploads of executable files, and represents a classic example of insecure file handling in web applications.
The technical exploitation of this vulnerability occurs through the manipulation of the elFinder file management component that the plugin utilizes for its functionality. Attackers can leverage the rename functionality to convert a potentially unsafe file extension into a PHP file, thereby gaining the ability to execute arbitrary code on the target server. This particular flaw allows adversaries to utilize the elFinder upload command to place malicious PHP code directly into the wp-content/plugins/wp-file-manager/lib/files/ directory, which serves as a critical attack surface since this location is typically accessible through the web root. The exploitation process specifically targets the plugin's failure to properly validate or sanitize file extensions during the upload process, creating a scenario where attackers can bypass normal security restrictions and establish persistent access to the compromised system.
The operational impact of CVE-2020-25213 extends far beyond simple code execution, as it provides attackers with complete control over the compromised WordPress installation and potentially the underlying server infrastructure. Once successful, attackers can deploy web shells, modify existing files, create new administrative accounts, or establish persistent backdoors that remain undetected for extended periods. This vulnerability directly maps to several ATT&CK techniques including T1059.007 for command and script injection, T1505.003 for server-side include, and T1078 for valid accounts, as the exploitation typically involves leveraging legitimate file upload mechanisms to gain unauthorized access. The fact that this vulnerability was actively exploited in the wild during August and September 2020 demonstrates its real-world threat potential and the urgency with which administrators should address such flaws in their WordPress environments.
The mitigation strategies for this vulnerability require immediate action from WordPress administrators, beginning with the mandatory upgrade of the File Manager plugin to version 6.9 or later, which contains the necessary patches to prevent the insecure file handling behavior. System administrators should also implement additional protective measures including restricting file upload permissions, monitoring for unusual file modifications in the plugin directories, and employing web application firewalls to detect and block suspicious upload attempts. Network-level defenses should focus on monitoring for known malicious patterns associated with elFinder exploitation attempts and implementing strict file type validation for all uploads. Organizations should also conduct comprehensive security audits of their WordPress installations to identify any other potentially vulnerable plugins or themes that may be susceptible to similar exploitation patterns, particularly those that utilize third-party file management components that may have similar insecure handling mechanisms.