CVE-2024-13898 in Simple Banner Plugin
Summary
by MITRE • 04/04/2025
The Simple Banner – Easily add multiple Banners/Bars/Notifications/Announcements to the top or bottom of your website plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 3.0.5 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.
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Analysis
by VulDB Data Team • 04/04/2025
The vulnerability identified as CVE-2024-13898 affects the Simple Banner WordPress plugin, specifically targeting versions up to and including 3.0.5. This represents a critical security flaw that exploits stored cross-site scripting vulnerabilities within the plugin's administrative settings. The issue stems from inadequate input sanitization and insufficient output escaping mechanisms that fail to properly validate or escape user-supplied data before it is stored and subsequently rendered in web pages. The vulnerability is particularly concerning because it requires only administrator-level permissions to exploit, making it accessible to authenticated attackers who can leverage their elevated privileges to compromise the WordPress installation.
The technical implementation of this vulnerability occurs within the plugin's admin interface where settings are processed and stored in the database. When administrators configure banner notifications through the plugin's interface, the input data is not adequately sanitized before persistence. This allows malicious actors to inject malicious scripts that are then stored and executed whenever legitimate users access pages containing the compromised banner content. The vulnerability specifically targets multi-site WordPress installations where the unfiltered_html capability has been disabled, creating an environment where attackers can bypass normal security restrictions that would otherwise prevent script injection. This exploitation pattern aligns with CWE-79, which classifies cross-site scripting vulnerabilities as a fundamental weakness in web application security.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with persistent access to compromised WordPress installations. Once an attacker successfully injects malicious code through the banner settings, the injected scripts will execute in the context of any user who views pages containing the compromised banner, potentially enabling session hijacking, data theft, or further compromise of the WordPress environment. The vulnerability affects the integrity of the entire website by allowing attackers to modify the content displayed to users, potentially redirecting them to malicious sites or stealing sensitive information. This threat is particularly dangerous in multi-site environments where a single compromised banner can affect multiple websites within the network, as the malicious scripts will execute across all affected installations.
Mitigation strategies for this vulnerability should focus on immediate patching of the Simple Banner plugin to version 3.0.6 or later, which contains the necessary input sanitization and output escaping fixes. Administrators should also implement strict access controls and regularly audit user permissions to minimize the risk of unauthorized access to administrative interfaces. The WordPress security community recommends disabling the unfiltered_html capability for non-privileged users and implementing additional security layers such as web application firewalls to monitor and block suspicious script injection attempts. Organizations should conduct thorough security assessments of their WordPress installations to identify any other plugins or themes that may be vulnerable to similar cross-site scripting attacks, as this vulnerability type remains one of the most prevalent and dangerous threats in web application security. The ATT&CK framework categorizes this vulnerability under T1059.001 for command and scripting interpreter, as the injected scripts can be used to execute arbitrary commands on affected systems, while T1566.001 covers the use of malicious notifications as a means of initial compromise.