CVE-2006-4317 in Burning Board
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in attachment.php in WoltLab Burning Board (WBB) 2.3.5 allows remote attackers to inject arbitrary web script or HTML via a GIF image that contains URL-encoded Javascript.
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Analysis
by VulDB Data Team • 09/20/2017
The vulnerability described in CVE-2006-4317 represents a critical cross-site scripting flaw within WoltLab Burning Board version 2.3.5, specifically affecting the attachment.php script. This issue enables remote attackers to execute malicious code through carefully crafted image files that contain URL-encoded javascript within their metadata or content. The vulnerability stems from insufficient input validation and sanitization mechanisms that fail to properly filter or escape user-supplied data before processing and rendering it within web pages. Attackers can exploit this weakness by uploading specially crafted GIF images that include malicious javascript code in their URL-encoded format, which then gets executed when other users view the attachment.
The technical implementation of this vulnerability involves the improper handling of file uploads and content rendering processes within the WBB platform. When users upload attachments, particularly image files, the system does not adequately sanitize the metadata or content of these files before storing or displaying them. This lack of proper validation allows malicious javascript code embedded within the GIF image to persist and execute in the context of other users' browsers. The vulnerability specifically targets the attachment.php script which handles the display and processing of uploaded files, making it a prime target for attackers seeking to compromise user sessions or steal sensitive information.
The operational impact of this vulnerability extends beyond simple script execution, potentially allowing attackers to perform session hijacking, deface websites, steal cookies, or redirect users to malicious sites. Users who view infected attachments become victims of the XSS attack, with their browser contexts being compromised. The attack vector is particularly dangerous because it leverages legitimate file upload functionality, making detection more difficult for security monitoring systems. This vulnerability undermines the trust model of the forum platform, as users expect that uploaded content will be safe to view without risk of executing malicious code.
The flaw aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities in web applications, and follows patterns commonly associated with ATT&CK technique T1566, which involves the use of malicious attachments to gain initial access to systems. Organizations using WBB 2.3.5 should implement immediate mitigations including input validation, output encoding, and file type restriction mechanisms. Security measures should focus on sanitizing all uploaded content, particularly image files, implementing Content Security Policy headers, and regularly updating the platform to patched versions. Additionally, administrators should consider implementing web application firewalls and monitoring for suspicious file upload patterns to prevent exploitation of this vulnerability.