CVE-2021-34653 in WP Fountain Plugin
Summary
by MITRE • 08/16/2021
The WP Fountain WordPress plugin is vulnerable to Reflected Cross-Site Scripting due to the use of $_SERVER['PHP_SELF'] in the ~/wp-fountain.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 1.5.9.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/19/2021
The WP Fountain WordPress plugin contains a critical reflected cross-site scripting vulnerability that affects versions up to and including 1.5.9. This vulnerability stems from improper input validation and sanitization within the plugin's core functionality, specifically in the wp-fountain.php file where the $_SERVER['PHP_SELF'] variable is utilized without adequate security measures. The flaw represents a classic XSS vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users, potentially compromising their sessions and data.
The technical implementation of this vulnerability occurs when the plugin processes user input through the PHP_SELF server variable, which contains the path of the current script. Attackers can craft malicious URLs that include script payloads in parameters or query strings, which are then reflected back to users without proper sanitization. This creates an environment where an attacker can execute arbitrary JavaScript code in the context of a victim's browser, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous in web applications where users interact with plugin interfaces.
The operational impact of this vulnerability extends beyond simple script injection, as it can be leveraged for more sophisticated attacks within the WordPress ecosystem. An attacker could potentially establish persistent XSS payloads that execute whenever a user visits affected pages, leading to long-term compromise of user sessions and potential privilege escalation. The reflected nature of this vulnerability means that attacks are typically delivered through social engineering tactics, where victims are tricked into clicking malicious links. This vulnerability directly maps to CWE-79, which describes improper neutralization of input during web page generation in a web application, and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments or links.
Mitigation strategies for this vulnerability should prioritize immediate plugin updates to versions that address the XSS flaw, as the vendor has likely released patches to resolve the issue. Administrators should implement comprehensive input validation and output encoding for all user-supplied data, particularly when using server variables like PHP_SELF in web applications. Additional protective measures include implementing Content Security Policy headers to limit script execution, using proper HTML escaping for all dynamic content, and conducting regular security audits of WordPress plugins. Organizations should also consider implementing web application firewalls to detect and block malicious payloads, while establishing monitoring procedures to identify potential exploitation attempts. The vulnerability demonstrates the critical importance of proper input sanitization in web applications and highlights the need for comprehensive security testing of third-party plugins before deployment in production environments.