CVE-2015-4153 in zM Ajax Login
Summary
by MITRE
Directory traversal vulnerability in the zM Ajax Login & Register plugin before 1.1.0 for WordPress allows remote attackers to include and execute arbitrary php files via a relative path in the template parameter in a load_template action to wp-admin/admin-ajax.php.
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Analysis
by VulDB Data Team • 03/16/2025
The directory traversal vulnerability identified as CVE-2015-4153 affects the zM Ajax Login & Register plugin for WordPress, specifically targeting versions prior to 1.1.0. This vulnerability represents a critical security flaw that enables remote attackers to manipulate the plugin's template loading mechanism through the admin-ajax.php endpoint. The flaw exists within the plugin's handling of the template parameter in the load_template action, creating an opportunity for unauthorized code execution. The vulnerability stems from insufficient input validation and sanitization of user-supplied parameters that are directly incorporated into file inclusion operations.
The technical implementation of this vulnerability involves the manipulation of the template parameter within the load_template action that is processed through the wp-admin/admin-ajax.php interface. Attackers can exploit this by crafting malicious requests that include relative path traversal sequences such as ../ or ..\ in the template parameter. When the plugin processes these requests, it fails to properly validate or sanitize the input, allowing the attacker to specify arbitrary PHP files for inclusion and execution. This creates a path traversal condition where the plugin's template loading mechanism can be manipulated to access files outside of its intended directory scope.
The operational impact of this vulnerability is severe and far-reaching within WordPress environments. Remote attackers can leverage this weakness to execute arbitrary PHP code on compromised systems, potentially leading to complete system compromise. The vulnerability allows attackers to include and execute malicious files from remote locations or local system directories, enabling them to perform actions such as data exfiltration, privilege escalation, or installation of backdoors. The attack surface is particularly concerning because it targets the admin-ajax.php endpoint, which is commonly used for legitimate administrative functions, making the exploitation less likely to be detected by standard security monitoring systems. This vulnerability can be exploited to gain unauthorized access to WordPress installations and potentially compromise entire web server infrastructures.
Mitigation strategies for CVE-2015-4153 should prioritize immediate plugin updates to version 1.1.0 or later, which contain the necessary patches to address the directory traversal vulnerability. Organizations should implement comprehensive input validation and sanitization measures for all user-supplied parameters, particularly those used in file inclusion operations. The principle of least privilege should be enforced by restricting file access permissions and ensuring that the plugin operates with minimal necessary privileges. Network-based security controls such as web application firewalls should be configured to monitor and block suspicious requests containing path traversal sequences. Additionally, regular security audits and vulnerability assessments should be conducted to identify and remediate similar weaknesses in other WordPress plugins and themes. This vulnerability aligns with CWE-22 Path Traversal and maps to ATT&CK techniques involving privilege escalation and remote code execution through web application vulnerabilities.