CVE-2024-4620 in ARForms Plugin
Summary
by MITRE • 06/07/2024
The ARForms - Premium WordPress Form Builder Plugin WordPress plugin before 6.6 allows unauthenticated users to modify uploaded files in such a way that PHP code can be uploaded when an upload file input is included on a form
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 07/12/2024
The ARForms WordPress plugin vulnerability CVE-2024-4620 represents a critical security flaw in versions prior to 6.6 that exposes WordPress sites to unauthorized file manipulation. This vulnerability specifically targets the plugin's file upload handling mechanism, creating a pathway for unauthenticated attackers to bypass normal security restrictions. The flaw exists within the form builder's upload processing logic where proper validation and sanitization of uploaded files are insufficiently implemented, allowing malicious actors to upload files containing PHP code without requiring authentication credentials.
The technical exploitation of this vulnerability occurs when a form contains an upload field that accepts file uploads from unauthenticated users. The plugin fails to properly validate file extensions, content types, or file contents, enabling attackers to upload malicious files that appear legitimate but contain executable PHP code. This weakness falls under the CWE-434 category of Unrestricted Upload of File with Dangerous Type, which is classified as a high-severity issue in the Common Weakness Enumeration framework. The vulnerability essentially creates a backdoor within the WordPress environment where attackers can execute arbitrary code on the server, potentially leading to complete system compromise.
From an operational impact perspective, this vulnerability allows attackers to gain persistent access to WordPress installations by uploading web shells or other malicious payloads. Once executed, these PHP files can be used to establish reverse shells, exfiltrate data, modify website content, or create additional attack vectors within the network. The unauthenticated nature of the exploit means that any visitor to a site with the vulnerable plugin can potentially compromise the system without needing to authenticate or possess any credentials. This makes the vulnerability particularly dangerous as it can be exploited continuously without detection, and the attack surface expands to include any website utilizing the affected plugin version.
The attack pattern aligns with ATT&CK technique T1505.003 for Server Software Component and T1078.004 for Valid Accounts, as attackers can leverage the vulnerability to gain unauthorized access through legitimate upload mechanisms. Organizations should immediately update to version 6.6 or later to remediate this vulnerability, as the patch addresses the core file validation issues that allowed malicious code execution. Additionally, implementing proper file upload restrictions at the web server level, using content security policies, and regularly monitoring file system changes can provide additional defense in depth. Security professionals should also conduct thorough audits of all WordPress installations to identify any other vulnerable plugins or themes that may be susceptible to similar file upload vulnerabilities, ensuring comprehensive protection against this class of attack.