CVE-2024-3754 in Alemha Watermarker Plugin
Summary
by MITRE • 06/14/2024
The Alemha watermarker WordPress plugin through 1.3.1 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)
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Analysis
by VulDB Data Team • 03/23/2025
The CVE-2024-3754 vulnerability affects the Alemha watermarker WordPress plugin version 1.3.1 and earlier, representing a critical stored cross-site scripting flaw that undermines the security model of WordPress installations. This vulnerability specifically targets the plugin's handling of user settings, where input validation and output escaping mechanisms are insufficiently implemented. The flaw allows attackers with administrative privileges to inject malicious scripts into plugin settings that persist in the database and execute whenever the settings are rendered in the admin interface or displayed on the frontend.
The technical nature of this vulnerability stems from the plugin's failure to properly sanitize user-provided input when processing configuration parameters. According to CWE-79, this represents a classic stored cross-site scripting vulnerability where malicious code is stored on the server and executed in the context of other users' browsers. The vulnerability is particularly concerning because it operates despite WordPress's built-in security measures that typically prevent unfiltered HTML input, especially in multisite environments where such protections are paramount. The plugin's insufficient sanitization means that even when the unfiltered_html capability is restricted, administrators can still inadvertently create persistent XSS vectors through the plugin's settings interface.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable sophisticated attacks including session hijacking, credential theft, and privilege escalation within the WordPress environment. Attackers can craft malicious payloads that exploit the stored XSS to gain unauthorized access to administrator accounts, potentially leading to complete compromise of the WordPress installation. The vulnerability's persistence in the database makes it particularly dangerous as it remains active until manually removed, and can affect multiple users who view the affected plugin settings. In multisite configurations, this vulnerability could allow attackers to compromise entire network installations through targeted attacks on individual sites.
Mitigation strategies for CVE-2024-3754 should include immediate plugin updates to versions that address the sanitization flaws, along with comprehensive security reviews of all plugin settings that accept user input. Administrators should implement additional security measures such as restricting administrative privileges to only essential personnel, monitoring plugin settings for unauthorized modifications, and deploying web application firewalls to detect and block XSS payloads. The vulnerability aligns with ATT&CK technique T1548.003 for privilege escalation and T1059.001 for command and scripting interpreter usage, making it a significant threat in the context of modern attack frameworks. Organizations should also consider implementing Content Security Policy headers to provide additional defense-in-depth against XSS exploitation attempts.