CVE-2022-4541 in Visitors Plugin
Summary
by MITRE • 09/26/2024
The WordPress Visitors plugin for WordPress is vulnerable to Stored Cross-Site Scripting via a spoofed HTTP Header value in versions up to, and including, 1.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses the nm_vistior page.
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Analysis
by VulDB Data Team • 03/09/2025
The WordPress Visitors plugin vulnerability represents a critical security flaw that undermines the integrity of web applications by enabling stored cross-site scripting attacks. This vulnerability exists within the plugin's handling of HTTP header values, specifically when processing data through the nm_vistior page functionality. The flaw allows attackers to inject malicious scripts that persist in the application's database, making the attack vector particularly dangerous as it can affect multiple users over time. The vulnerability affects all versions up to and including version 1.0, indicating that this was likely an early implementation flaw that was never properly addressed through security hardening measures.
The technical root cause of this vulnerability stems from inadequate input sanitization and insufficient output escaping mechanisms within the plugin's codebase. When HTTP header values are processed without proper validation, the plugin fails to sanitize potentially malicious content before storing it in the database. This creates a persistent XSS vector where attacker-controlled scripts can be executed in the context of any user who visits the affected nm_vistior page. The vulnerability operates at the application layer, specifically targeting the plugin's data handling and rendering processes, and can be exploited through HTTP headers without requiring any authentication from the attacker. This characteristic places the vulnerability in the category of server-side input validation failures that align with CWE-79, which describes cross-site scripting vulnerabilities due to insufficient input sanitization.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, data theft, and redirection to malicious sites. An attacker could inject scripts that steal user cookies, capture login credentials, or redirect victims to phishing pages that appear legitimate. The unauthenticated nature of the attack means that any user visiting the affected page could become compromised, potentially affecting administrators, regular users, or both depending on the site's configuration. This vulnerability particularly affects WordPress installations using the Visitors plugin, creating a widespread risk across numerous websites that have not updated to patched versions. The stored nature of the vulnerability means that once exploited, the malicious scripts remain active until manually removed from the database, providing attackers with persistent access to compromised systems.
Mitigation strategies for this vulnerability should focus on immediate patching of the plugin to version 1.1 or later, which contains the necessary security fixes. Administrators should also implement additional security measures including input validation at multiple layers, regular security audits of installed plugins, and monitoring for suspicious HTTP header values. The implementation of Content Security Policies can provide additional protection against script execution, while regular database backups ensure that malicious modifications can be restored. Security professionals should also consider implementing web application firewalls that can detect and block suspicious header values. Organizations should conduct comprehensive vulnerability assessments to identify other potentially affected plugins and ensure that all WordPress installations maintain up-to-date security patches. This vulnerability demonstrates the importance of proper input sanitization and output escaping practices, aligning with ATT&CK technique T1213 which covers data from information repositories, and highlights the need for robust application security controls throughout the software development lifecycle.