CVE-2016-1564 in WordPress
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in wp-includes/class-wp-theme.php in WordPress before 4.4.1 allow remote attackers to inject arbitrary web script or HTML via a (1) stylesheet name or (2) template name to wp-admin/customize.php.
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Analysis
by VulDB Data Team • 10/14/2024
The vulnerability identified as CVE-2016-1564 represents a critical cross-site scripting flaw discovered in WordPress versions prior to 4.4.1, specifically within the wp-includes/class-wp-theme.php file. This weakness resides in the theme customization functionality accessible through the wp-admin/customize.php interface, making it particularly dangerous as it allows attackers to exploit the administrative interface without requiring authentication. The vulnerability manifests when user-supplied input containing malicious scripts is processed during theme customization operations, specifically when handling stylesheet names or template names. The flaw stems from insufficient input validation and output escaping mechanisms that fail to properly sanitize data before it is rendered in the web interface, creating an environment where malicious payloads can be executed in the context of authenticated users' browsers.
The technical exploitation of this vulnerability occurs through the manipulation of parameters passed to the customize.php endpoint, where attackers can inject malicious JavaScript code into the stylesheet or template name fields. When these values are subsequently displayed in the theme customization interface, the injected scripts execute in the browser context of any user who views the affected page, potentially leading to session hijacking, credential theft, or unauthorized administrative actions. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically classified as a reflected XSS attack vector, where malicious input is immediately reflected back to the user's browser without proper sanitization. The attack chain typically involves an attacker crafting malicious payloads that exploit the lack of proper input validation in the WordPress theme customization subsystem, which then gets executed when administrators or other users view the customized theme settings.
The operational impact of CVE-2016-1564 extends beyond simple script injection, as it provides attackers with a potential foothold for more sophisticated attacks within WordPress installations. When exploited successfully, this vulnerability can enable attackers to escalate privileges, access sensitive administrative functions, or steal session cookies from authenticated users. The vulnerability affects WordPress installations that have not been updated to version 4.4.1 or later, leaving millions of websites potentially exposed to this attack vector. The implications are particularly severe for WordPress administrators who may unknowingly click on malicious links or visit compromised websites that trigger the XSS payload, as the attack requires no special privileges or authentication credentials to execute. Security researchers have noted that this vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as it leverages JavaScript execution within the browser context to perform malicious activities.
Mitigation strategies for CVE-2016-1564 focus primarily on immediate patching of affected WordPress installations to version 4.4.1 or later, which includes proper input sanitization and output escaping mechanisms. Organizations should implement comprehensive security monitoring to detect unauthorized modifications to theme customization parameters and establish robust input validation procedures that prevent malicious data from being processed through the affected interface. Additional protective measures include implementing content security policies that restrict script execution within the WordPress administrative interface, disabling unnecessary user capabilities that might allow theme customization access, and conducting regular security audits of WordPress installations to identify and remediate similar vulnerabilities. The vulnerability demonstrates the critical importance of input validation and output escaping in web applications, as highlighted by security frameworks that emphasize the need for proper sanitization of all user-supplied data before it is rendered in web interfaces.