CVE-2019-15826 in wps-hide-login Plugin
Summary
by MITRE
The wps-hide-login plugin before 1.5.3 for WordPress has a protection bypass via wp-login.php in the Referer field.
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Analysis
by VulDB Data Team • 12/11/2023
The vulnerability identified as CVE-2019-15826 affects the wps-hide-login plugin for WordPress, specifically versions prior to 1.5.3, presenting a critical security flaw that undermines the plugin's intended protection mechanisms. This issue manifests through a referer field manipulation technique that allows unauthorized users to bypass the login page protection measures implemented by the plugin. The wps-hide-login plugin is designed to obscure the standard WordPress login endpoint by hiding the wp-login.php page, thereby preventing automated attacks and brute force attempts that target the conventional login path. However, this vulnerability creates a pathway for attackers to circumvent these protective measures through manipulation of HTTP referer headers.
The technical flaw resides in how the plugin validates the referer field during authentication attempts, failing to properly sanitize or verify the origin of requests. When a user attempts to access the login page, the plugin relies on the referer header to determine whether the request originated from a legitimate source within the WordPress installation. Attackers can exploit this by crafting requests with manipulated referer headers that appear to originate from trusted locations within the site, effectively tricking the plugin's validation logic into allowing access to the hidden login page. This bypass mechanism represents a classic example of insecure input validation where the plugin fails to implement robust verification of the referer header values, leaving the authentication process vulnerable to manipulation.
The operational impact of this vulnerability extends beyond simple access bypass, potentially enabling a range of malicious activities including credential stuffing attacks, brute force attempts, and automated exploitation of the WordPress installation. Security researchers have classified this issue as a protection mechanism bypass, which aligns with CWE-693, representing protection mechanism failure. The vulnerability creates a direct pathway for attackers to target the WordPress login system without the protective measures that the plugin was designed to provide, effectively neutralizing the security benefits that administrators expected from installing this specific plugin. This flaw particularly affects WordPress installations that rely on third-party plugins for additional security layers, as it demonstrates how a single vulnerability in a security plugin can compromise the entire authentication infrastructure.
Organizations and WordPress administrators should prioritize immediate remediation by updating the wps-hide-login plugin to version 1.5.3 or later, which contains the necessary patches to address the referer field validation weakness. Additionally, system administrators should implement layered security approaches including strong authentication measures, rate limiting, and monitoring of login attempts to detect anomalous access patterns that may indicate exploitation attempts. The vulnerability also highlights the importance of proper input validation and secure coding practices, as outlined in the OWASP Top 10 security standards. Security teams should consider implementing network-level protections such as web application firewalls that can detect and block suspicious referer header patterns, while also conducting regular security audits of installed plugins to ensure compliance with current security best practices and to identify potential vulnerabilities before they can be exploited by malicious actors.