CVE-2018-15818 in ARForms
Summary
by MITRE
An issue was discovered in Repute ARForms 3.5.1 and prior. An attacker is able to delete any file on the server with web server privileges by sending a malicious request to admin-ajax.php.
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Analysis
by VulDB Data Team • 08/03/2023
The vulnerability identified as CVE-2018-15818 represents a critical file deletion flaw within the Repute ARForms WordPress plugin version 3.5.1 and earlier. This issue stems from inadequate input validation and access control mechanisms within the plugin's administrative AJAX handler. The vulnerability allows unauthenticated attackers to exploit a path traversal or direct file manipulation vulnerability by sending crafted requests to the admin-ajax.php endpoint, which serves as a central hub for WordPress administrative functions. The flaw exists because the plugin fails to properly validate user permissions or sanitize file paths before executing file operations, creating a dangerous attack surface that can be leveraged by malicious actors to compromise server integrity.
The technical exploitation of this vulnerability occurs through the manipulation of parameters sent to the admin-ajax.php script, which processes administrative requests without sufficient authorization checks. When an attacker crafts a malicious request that includes specific file paths or manipulation parameters, the plugin's backend code processes these inputs without proper validation, leading to arbitrary file deletion on the web server. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. The issue also aligns with CWE-73, which covers external control of filename or path, as the attacker can manipulate file paths through external inputs. The flaw demonstrates poor input sanitization practices and inadequate access control implementation, creating a dangerous condition where any user can potentially delete critical system files, configuration files, or even executable code.
The operational impact of this vulnerability extends beyond simple file deletion, as it can lead to complete system compromise and data loss. An attacker with access to the vulnerable plugin can delete critical WordPress core files, theme files, plugin files, or database configuration files, effectively rendering the website unusable or creating opportunities for further exploitation. The vulnerability particularly affects WordPress installations where the ARForms plugin is installed and active, creating a persistent threat vector that remains active until the plugin is updated or removed. This type of vulnerability enables attackers to perform destructive operations that can result in complete website downtime, data breaches, or serve as a foothold for more sophisticated attacks. The impact is amplified because the vulnerability does not require authentication, making it particularly dangerous for publicly accessible web applications.
Security mitigations for this vulnerability should begin with immediate plugin updates to versions that address the file deletion flaw, as the vendor likely released patches to fix the input validation issues. Organizations should implement network-level restrictions to limit access to administrative endpoints, particularly admin-ajax.php, by implementing proper firewall rules and access controls. The use of web application firewalls can help detect and block malicious requests attempting to exploit this vulnerability by monitoring for suspicious parameter patterns. Additionally, implementing proper input validation and output encoding practices, along with regular security audits of WordPress plugins, can prevent similar vulnerabilities from being introduced. According to ATT&CK framework, this vulnerability maps to T1059.001 for command and scripting interpreter and T1486 for data destruction, as it enables attackers to perform destructive operations on target systems. Regular security monitoring and vulnerability scanning should be implemented to identify and remediate similar issues across the entire WordPress ecosystem, particularly focusing on administrative AJAX endpoints that handle file operations.