CVE-2015-9378 in iThemes Builder Theme Market
Summary
by MITRE
iThemes Builder Theme Market before 5.1.27 for WordPress has XSS via add_query_arg() and remove_query_arg().
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Analysis
by VulDB Data Team • 12/07/2023
The vulnerability CVE-2015-9378 affects the iThemes Builder Theme Market plugin version 5.1.26 and earlier for WordPress, representing a cross-site scripting vulnerability that exploits improper input validation within the plugin's handling of URL query parameters. This issue specifically involves the add_query_arg() and remove_query_arg() functions which are fundamental WordPress utility functions used for manipulating URL query strings. The flaw arises when these functions process user-supplied input without adequate sanitization, creating an avenue for malicious actors to inject malicious scripts into web pages viewed by other users.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize query parameters before incorporating them into dynamically generated HTML content. When users navigate to pages that utilize the affected plugin functions, the malicious scripts embedded within the unsanitized query arguments execute in the context of other users' browsers. This occurs because the WordPress core functions add_query_arg() and remove_query_arg() are designed to handle URL manipulation but do not perform the necessary output escaping when the modified URLs are subsequently rendered in web pages. The vulnerability manifests as a classic reflected cross-site scripting vector where the malicious payload is reflected back to users through the plugin's response handling.
The operational impact of this vulnerability extends beyond simple script execution as it enables attackers to perform various malicious activities including session hijacking, credential theft, and redirection to malicious sites. Attackers can craft specially formatted URLs containing malicious JavaScript payloads that, when visited by authenticated users with sufficient privileges, can compromise the entire WordPress installation. The vulnerability affects not only regular users but also administrators who might inadvertently click on malicious links, potentially leading to complete system compromise. The reflected nature of the vulnerability means that attackers do not need to store malicious content on the server, making detection and mitigation more challenging.
Security practitioners should note that this vulnerability aligns with CWE-79 Cross-site Scripting and follows patterns commonly observed in WordPress plugin vulnerabilities where input validation and output sanitization are insufficient. The ATT&CK framework categorizes this as a web application attack vector under T1190 Exploit Public-Facing Application, where attackers leverage known vulnerabilities in web applications to execute malicious code. Organizations should prioritize immediate patching to version 5.1.27 or later, as the vulnerability affects the core functionality of the plugin and provides attackers with a straightforward path to compromise user sessions and potentially gain administrative control. Additional mitigations include implementing web application firewalls to detect and block malicious query parameter patterns and conducting regular security audits of installed WordPress plugins to identify similar vulnerabilities. The vulnerability underscores the importance of proper input validation and output escaping practices in web application development, particularly within content management systems where plugins extend core functionality.