CVE-2015-5483 in Private Only Plugin
Summary
by MITRE
Multiple cross-site request forgery (CSRF) vulnerabilities in the Private Only plugin 3.5.1 for WordPress allow remote attackers to hijack the authentication of administrators for requests that (1) add users, (2) delete posts, or (3) modify PHP files via unspecified vectors, or (4) conduct cross-site scripting (XSS) attacks via the po_logo parameter in the privateonly.php page to wp-admin/options-general.php.
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Analysis
by VulDB Data Team • 03/25/2025
The CVE-2015-5483 vulnerability represents a critical security flaw in the Private Only WordPress plugin version 3.5.1 that exposes administrators to sophisticated attack vectors through cross-site request forgery mechanisms. This vulnerability specifically targets the plugin's handling of administrative functions within the WordPress administration interface, creating opportunities for remote attackers to execute unauthorized actions with elevated privileges. The flaw stems from inadequate validation of request origins and missing anti-CSRF tokens in critical administrative endpoints, allowing malicious actors to manipulate legitimate administrative sessions for unauthorized operations.
The technical implementation of this vulnerability manifests through multiple attack vectors that exploit the absence of proper CSRF protection mechanisms within the plugin's codebase. Attackers can leverage these weaknesses to perform unauthorized administrative actions such as adding new users to the WordPress installation, deleting existing posts, or modifying PHP configuration files that could lead to complete system compromise. The vulnerability particularly affects the privateonly.php page located within the wp-admin/options-general.php administrative interface, where the po_logo parameter becomes a primary attack surface. This parameter lacks proper input sanitization and validation, creating opportunities for both CSRF and cross-site scripting exploitation simultaneously.
The operational impact of CVE-2015-5483 extends beyond simple privilege escalation to encompass potential complete system compromise and data destruction. When successful, these attacks can result in persistent backdoor access through new user account creation, content manipulation through post deletion, or code injection via PHP file modifications. The cross-site scripting component further amplifies the threat by allowing attackers to execute malicious scripts within the administrator's browser context, potentially leading to session hijacking, credential theft, or additional attack vectors. This vulnerability directly violates security principles outlined in CWE-352, which specifically addresses cross-site request forgery vulnerabilities, and aligns with ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting through social engineering and automated attacks.
Organizations affected by this vulnerability should implement immediate mitigations including plugin updates to versions that address the CSRF protection gaps, implementation of web application firewalls to detect and block suspicious requests, and comprehensive monitoring of administrative activities for unauthorized modifications. Network segmentation and least privilege access controls should be enforced to limit the potential damage from successful exploitation attempts. Additionally, administrators should conduct thorough security audits of all installed WordPress plugins, particularly those with administrative functionality, and ensure proper input validation and output encoding practices are implemented throughout the application stack. The vulnerability demonstrates the critical importance of proper CSRF token implementation and request origin verification, principles that align with OWASP Top Ten security requirements and fundamental web application security best practices established in NIST SP 800-53 security controls.