CVE-2016-10990 in wp-cerber Plugin
Summary
by MITRE
The wp-cerber plugin before 2.7 for WordPress has XSS via the X-Forwarded-For HTTP header.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 12/26/2023
The wp-cerber plugin for WordPress versions prior to 2.7 contained a cross-site scripting vulnerability that emerged from improper handling of the X-Forwarded-For HTTP header. This vulnerability falls under the CWE-79 category of Cross-Site Scripting, specifically representing a reflected XSS flaw where malicious input from the HTTP header was not properly sanitized before being rendered in the web application's response. The vulnerability exploited the plugin's failure to validate or escape user-supplied data originating from the X-Forwarded-For header, which is commonly used by web servers to identify the original IP address of a client connecting through a proxy or load balancer.
The technical implementation of this vulnerability occurred when the wp-cerber plugin processed incoming requests and directly incorporated the X-Forwarded-For header value into its output without adequate input sanitization. When an attacker crafted a malicious payload within this header and sent it to a vulnerable WordPress site, the plugin would render this unescaped content in the administrative interface or user-facing pages, creating an opportunity for attackers to execute arbitrary JavaScript code in the context of other users' browsers. This flaw was particularly dangerous because it could be exploited by attackers who had no direct access to the WordPress installation but could influence the HTTP headers of requests passing through a proxy or load balancer.
The operational impact of this vulnerability extended beyond simple script execution as it provided attackers with the ability to perform session hijacking, steal administrative credentials, or manipulate the WordPress administrative interface. Attackers could potentially escalate privileges by executing malicious scripts that captured user sessions or modified plugin functionality. The vulnerability was especially concerning in environments where WordPress sites were behind reverse proxies or load balancers that set the X-Forwarded-For header, making exploitation more likely in production environments. This flaw could also enable attackers to perform persistent XSS attacks against other users who viewed affected pages, creating a broader attack surface within the WordPress installation.
Security mitigations for this vulnerability involved updating to wp-cerber plugin version 2.7 or later, which implemented proper input validation and output escaping for HTTP headers. Organizations should also implement comprehensive header sanitization policies at the web server level, ensuring that the X-Forwarded-For header is properly validated before being passed to WordPress applications. Network-level protections including web application firewalls and HTTP header filtering could provide additional defense-in-depth measures. The vulnerability aligns with ATT&CK technique T1059.007 for script injection and T1566 for credential access, demonstrating how seemingly benign HTTP headers can become attack vectors when improperly handled by web applications. Organizations should maintain updated plugin inventories and implement automated vulnerability scanning to identify similar issues in other WordPress plugins that may process HTTP headers without proper sanitization.