CVE-2008-6431 in BMForum
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in BMForum 5.6 allow remote attackers to inject arbitrary web script or HTML via the (1) outpused parameter to index.php, the (2) footer_copyright and (3) verandproname parameters to newtem/footer/bsd01footer.php, and the (4) topads and (5) myplugin parameters to newtem/header/bsd01header.php.
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Analysis
by VulDB Data Team • 04/07/2025
The CVE-2008-6431 vulnerability represents a critical cross-site scripting flaw affecting BMForum version 5.6, a web-based discussion platform that was widely used for online community management. This vulnerability exposes the application to persistent security risks by allowing remote attackers to inject malicious scripts into web pages viewed by other users. The flaw manifests across multiple entry points within the application's template system, specifically targeting parameter handling in three distinct files that control the forum's visual presentation and user interface elements. The vulnerability's impact extends beyond simple script injection, as it enables attackers to manipulate the entire user experience and potentially compromise user sessions or steal sensitive information from authenticated users.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the BMForum application's template processing mechanisms. Attackers can exploit the vulnerability by crafting malicious payloads and submitting them through the identified parameters in the affected php files. The outpused parameter in index.php accepts unvalidated input that gets directly embedded into the page output without proper HTML encoding or script filtering. Similarly, the footer_copyright and verandproname parameters in bsd01footer.php, along with topads and myplugin parameters in bsd01header.php, fail to implement adequate sanitization measures, allowing attackers to inject HTML tags and javascript code that executes in the context of other users' browsers. This represents a classic case of insufficient input validation as defined by CWE-79, which specifically addresses cross-site scripting vulnerabilities in web applications.
The operational impact of CVE-2008-6431 is substantial and multifaceted, affecting both user security and application integrity. When exploited, these vulnerabilities can enable attackers to perform session hijacking, steal user credentials, redirect victims to malicious websites, or inject malicious advertisements into forum pages. The vulnerability's reach extends to all users interacting with the forum, as any content generated through the affected parameters becomes a potential vector for attack. Additionally, the persistence of these vulnerabilities in the template files suggests that the flaw exists at a fundamental level within the application's architecture rather than being isolated to specific functions, making it particularly dangerous for long-term operation. The vulnerability also aligns with ATT&CK technique T1566.001, which describes the use of web shell injection and script injection techniques to establish persistent access to web applications.
Mitigation strategies for CVE-2008-6431 require immediate implementation of comprehensive input validation and output encoding measures throughout the affected application components. Organizations should implement strict parameter validation for all user-supplied input, particularly in template files where the vulnerability occurs. The recommended approach involves applying HTML entity encoding to all output generated from user-provided data, ensuring that special characters are properly escaped before being rendered in web pages. Additionally, implementing Content Security Policy headers can provide an additional layer of protection against script injection attacks by restricting the sources from which scripts can be loaded. The vulnerability also demonstrates the importance of secure coding practices and proper input sanitization, which aligns with CWE-116 requirements for proper encoding of output data. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other application components, particularly in legacy systems that may not have received regular security updates. The remediation process should include patching the affected version of BMForum to a secure release or implementing custom sanitization routines for the vulnerable parameters in the template files to prevent unauthorized script execution.