CVE-2016-10964 in dwnldr Plugin
Summary
by MITRE
The dwnldr plugin before 1.01 for WordPress has XSS via the User-Agent HTTP header.
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Analysis
by VulDB Data Team • 12/25/2023
The CVE-2016-10964 vulnerability affects the dwnldr plugin version 1.00 and earlier for WordPress, representing a cross-site scripting flaw that exploits the User-Agent HTTP header. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is a critical security weakness that allows attackers to inject malicious scripts into web applications. The issue specifically targets the plugin's handling of HTTP headers without proper sanitization or validation, creating an attack surface where user input can be manipulated to execute arbitrary code in the context of other users' browsers. The vulnerability is particularly concerning because it leverages the User-Agent header, which is automatically sent by web browsers and often used for various purposes including browser detection and user tracking.
The technical implementation of this vulnerability occurs when the dwnldr plugin processes the User-Agent HTTP header without adequate input validation or output encoding. When a malicious actor crafts a User-Agent string containing script code, the plugin fails to sanitize this input before displaying it on the web interface or logging it in administrative panels. This allows an attacker to inject HTML or JavaScript code that executes in the context of other users who view affected pages or administrative interfaces. The vulnerability is classified as a reflected XSS attack since the malicious payload is reflected back to users through the plugin's output mechanism, making it particularly dangerous in environments where administrators frequently monitor user activity logs or browser information displays.
The operational impact of CVE-2016-10964 extends beyond simple script injection, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and privilege escalation. When administrators access plugin interfaces or user activity logs, they become potential victims of the XSS attack, allowing attackers to steal administrative sessions or manipulate plugin functionality. The vulnerability also creates opportunities for attackers to establish persistent access through more sophisticated attacks that leverage the initial XSS vector, potentially leading to complete system compromise. This weakness is particularly dangerous in WordPress environments where plugins often have elevated privileges and can access sensitive data or modify system configurations.
Mitigation strategies for CVE-2016-10964 should include immediate plugin updates to version 1.01 or later, which contains the necessary fixes for proper input sanitization. Organizations should implement comprehensive input validation and output encoding mechanisms to prevent similar vulnerabilities in other components, following the principle of least privilege and secure coding practices. The remediation process should also involve reviewing all installed plugins for similar vulnerabilities and implementing web application firewalls to detect and block malicious User-Agent headers. Security teams should monitor for exploitation attempts and ensure that proper logging and monitoring systems are in place to detect unauthorized access attempts. Additionally, administrators should consider implementing Content Security Policy headers to provide an additional layer of protection against XSS attacks, as recommended in the OWASP Top Ten security guidelines and aligned with ATT&CK technique T1212 for exploitation of web application vulnerabilities.