CVE-2016-7168 in WordPress
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the media_handle_upload function in wp-admin/includes/media.php in WordPress before 4.6.1 might allow remote attackers to inject arbitrary web script or HTML by tricking an administrator into uploading an image file that has a crafted filename.
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Analysis
by VulDB Data Team • 10/27/2022
The CVE-2016-7168 vulnerability represents a critical cross-site scripting flaw within the WordPress content management system that existed prior to version 4.6.1. This vulnerability specifically resides in the media_handle_upload function located in the wp-admin/includes/media.php file, making it a server-side processing issue that affects how WordPress handles media file uploads. The flaw stems from insufficient input validation and sanitization of filename parameters during the upload process, creating an avenue for malicious actors to exploit the system's trust in user-provided data. The vulnerability operates under the CWE-79 principle of cross-site scripting, where untrusted data flows into web applications without proper escaping or validation, allowing attackers to execute malicious scripts in the context of other users' browsers.
The technical exploitation of this vulnerability requires an attacker to craft a malicious filename that contains embedded script code, typically in the form of javascript or html tags, which gets processed by the vulnerable media handling function. When an administrator uploads such a crafted file, the system processes the filename without adequate sanitization, potentially storing or displaying the malicious content in contexts where it can be executed. The attack vector relies on social engineering tactics where administrators are tricked into uploading seemingly legitimate media files that contain hidden malicious payloads within their filenames. This creates a scenario where the vulnerability can be triggered through normal administrative upload operations, making it particularly dangerous as it doesn't require elevated privileges beyond standard user access to initiate the attack.
The operational impact of CVE-2016-7168 extends beyond simple script execution, as it can lead to complete compromise of administrator sessions through session hijacking, credential theft, or redirection to malicious sites. The vulnerability can be leveraged to perform actions such as modifying website content, accessing sensitive administrative functions, or stealing cookies and authentication tokens from authenticated users. Attackers can exploit this weakness to establish persistent access to compromised WordPress installations, potentially leading to full site takeover. The risk is amplified because administrators typically trust the upload process and may not scrutinize filenames carefully, making this vulnerability particularly effective in real-world exploitation scenarios. This aligns with the ATT&CK framework's technique T1059.007 for command and scripting interpreter, where attackers can execute malicious code through web-based interfaces.
The mitigation strategies for this vulnerability primarily involve immediate patching to WordPress version 4.6.1 or later, which includes proper input sanitization and validation of filename parameters. Organizations should implement additional defensive measures such as restricting upload file types to only allow safe extensions, implementing filename sanitization at the application level, and monitoring upload activities for suspicious patterns. Network-based protections like web application firewalls can help detect and block malicious upload attempts, while security monitoring should focus on identifying unusual administrator upload behaviors. The vulnerability highlights the importance of input validation and the principle of least privilege in web application security, as it demonstrates how insufficient sanitization of user-provided data can create significant security risks. Organizations should also consider implementing Content Security Policy headers and regular security audits of their WordPress installations to prevent similar vulnerabilities from being exploited in the future.