CVE-2018-11709 in Forum plugin
Summary
by MITRE
wpforo_get_request_uri in wpf-includes/functions.php in the wpForo Forum plugin before 1.4.12 for WordPress allows Unauthenticated Reflected Cross-Site Scripting (XSS) via the URI.
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Analysis
by VulDB Data Team • 02/14/2020
The wpForo Forum plugin for WordPress represents a widely used community building solution that enables users to create discussion forums within their wordpress environments. This particular vulnerability exists within the wpf-includes/functions.php file in versions prior to 1.4.12, specifically affecting the wpforo_get_request_uri function. The flaw manifests as an unauthenticated reflected cross-site scripting vulnerability that can be exploited by remote attackers without requiring any login credentials or privileged access to the wordpress installation. The vulnerability occurs when the plugin fails to properly sanitize or escape user-supplied URI parameters before outputting them back to the browser, creating a pathway for malicious script execution in the context of the victim's browser session.
The technical implementation of this vulnerability stems from improper input validation and output encoding practices within the wpforo_get_request_uri function. When a user navigates to a wpForo forum page with maliciously crafted URI parameters, the function processes these inputs without adequate sanitization measures. The reflected nature of the vulnerability means that the malicious payload is embedded directly into the URI and then reflected back to the user's browser through the plugin's output mechanism. This creates a scenario where an attacker can craft a URL containing malicious javascript code that, when visited by an unsuspecting user, executes in the user's browser context with the privileges of that user. The vulnerability specifically affects the plugin's handling of request URI parameters, making it particularly dangerous as it can be triggered through normal navigation patterns within the forum interface.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to perform a range of malicious activities within the context of the affected wordpress installation. An attacker could potentially steal user session cookies, redirect users to malicious websites, inject phishing content, or even escalate privileges if the targeted users have administrative access to the wordpress site. The unauthenticated nature of the vulnerability means that any user visiting the maliciously crafted URL could be compromised, making this a significant threat to forum administrators and their users. The reflected XSS nature also makes it difficult to detect and prevent, as the malicious code is delivered through legitimate plugin functionality rather than being stored on the server, which complicates traditional security monitoring approaches. This vulnerability can be exploited in various attack scenarios including social engineering campaigns where attackers send malicious links via email or other communication channels to target specific user groups within the forum community.
Mitigation strategies for this vulnerability center around immediate plugin updates to version 1.4.12 or later, which contain the necessary patches to properly sanitize URI parameters before output. System administrators should also implement additional security layers including web application firewalls that can detect and block malicious URI patterns, input validation rules that prevent suspicious characters from being processed, and comprehensive monitoring of forum access logs for unusual navigation patterns. Organizations should consider implementing content security policies that limit script execution within the forum context and establish regular security audits of installed plugins to identify other potential vulnerabilities. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and can be mapped to ATT&CK technique T1566.001 which covers social engineering via spearphishing. Proper security hygiene including regular plugin updates, user education about suspicious links, and maintaining current security tooling provides the most effective defense against this class of vulnerability.