CVE-2012-6556 in FirstLastNames
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in the FirstLastNames plugin 1.1.1 for Vanilla Forums allow remote attackers to inject arbitrary web script or HTML via the (1) User/FirstName or (2) User/LastName parameter to the edit user page. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 05/23/2025
The CVE-2012-6556 vulnerability represents a critical cross-site scripting flaw within the FirstLastNames plugin version 1.1.1 for Vanilla Forums, a widely used open-source discussion platform. This vulnerability exposes the system to remote code execution risks through malicious web script injection, potentially compromising user sessions and data integrity. The vulnerability specifically affects the edit user page functionality where user input is not properly sanitized or validated before being rendered back to users. The attack vector exploits two distinct parameter injection points: User/FirstName and User/LastName, which are commonly used fields in user profile management systems. This type of vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a critical weakness in web application security that allows attackers to inject malicious scripts into web pages viewed by other users.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the plugin's user management interface. When administrators or users access the edit user page, the plugin fails to properly escape or sanitize user-supplied data before rendering it back to the browser. This creates an environment where malicious actors can craft specially formatted input strings containing embedded javascript or html code that executes in the context of other users' browsers. The vulnerability is particularly dangerous because it operates at the user profile level where legitimate users might have elevated privileges or access to sensitive information. The lack of proper sanitization means that any script code entered into the FirstName or LastName fields gets executed when other users view the profile information, creating a persistent threat vector that can affect multiple users simultaneously.
The operational impact of CVE-2012-6556 extends beyond simple script injection to potentially enable more sophisticated attacks including session hijacking, credential theft, and data exfiltration. Attackers could craft malicious payloads that redirect users to phishing sites, steal authentication cookies, or even execute arbitrary commands on affected systems through browser-based attacks. The vulnerability's persistence nature means that once exploited, malicious scripts remain active until the affected plugin is updated or the compromised user data is manually corrected. This creates long-term security risks for organizations relying on Vanilla Forums for community engagement, customer support, or internal collaboration platforms where user profiles contain sensitive information. The vulnerability also demonstrates the importance of proper input validation and output encoding practices, which are fundamental requirements in the OWASP Top Ten security framework and align with defense-in-depth strategies outlined in the MITRE ATT&CK framework under the execution and credential access phases.
Organizations affected by this vulnerability should immediately implement mitigation strategies including plugin updates to versions that address the XSS flaws, input sanitization measures, and enhanced monitoring of user profile modifications. The recommended approach involves applying the vendor-supplied security patches, implementing web application firewalls with XSS detection capabilities, and conducting thorough security assessments of all installed plugins. Additionally, administrators should consider implementing Content Security Policy headers to limit script execution and establish proper input validation routines that escape or filter malicious content before processing user submissions. Regular security audits and vulnerability scanning should be conducted to identify similar issues in other plugins or custom-developed components. The vulnerability highlights the critical need for continuous security monitoring and the importance of maintaining up-to-date software components in web applications to prevent exploitation of known security flaws.