CVE-2005-0692 in PHP-Fusion
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in fusion_core.php for PHP-Fusion 5.x allows remote attackers to inject arbitrary web script or HTML via a message with IMG bbcode containing character-encoded Javascript.
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Analysis
by VulDB Data Team • 05/30/2019
The vulnerability identified as CVE-2005-0692 represents a critical cross-site scripting flaw discovered in PHP-Fusion version 5.x, specifically within the fusion_core.php component. This vulnerability falls under the Common Weakness Enumeration category CWE-79, which defines improper neutralization of input during web page generation as a fundamental weakness in web application security. The flaw manifests when the application fails to properly sanitize user input containing bbcode tags, particularly the IMG tag, which allows malicious actors to embed character-encoded javascript within image references.
The technical exploitation of this vulnerability occurs through the manipulation of the message parameter within the fusion_core.php script. Attackers can craft malicious input containing IMG bbcode tags with javascript payloads encoded in various character encodings such as html entities or url encoding. When the vulnerable PHP-Fusion application processes these messages and renders them on web pages without proper output encoding or sanitization, the embedded javascript executes in the context of other users' browsers. This creates a persistent cross-site scripting vector that can be leveraged for session hijacking, credential theft, or redirection to malicious sites.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the ability to manipulate the application's user interface and compromise user sessions. According to the MITRE ATT&CK framework, this vulnerability maps to the T1059.007 technique for command and control through scripting languages, enabling attackers to establish persistent access through client-side exploits. The vulnerability affects all versions of PHP-Fusion 5.x, making it particularly dangerous as it represents a widespread flaw in a popular content management system. Users who view affected posts become victims of the attack, as their browsers execute the malicious javascript without proper security boundaries.
Mitigation strategies for this vulnerability require immediate implementation of input sanitization and output encoding measures. The most effective approach involves implementing strict validation of all user-supplied input, particularly within bbcode processing functions, and ensuring that any character encoding is properly decoded and validated before rendering. Organizations should implement Content Security Policy headers to limit script execution, employ proper HTML escaping mechanisms when displaying user content, and consider implementing web application firewalls to detect and block suspicious input patterns. The vulnerability demonstrates the critical importance of proper input validation and output encoding in preventing client-side attacks, as outlined in the OWASP Top Ten security principles. Regular security audits and patch management processes should be implemented to prevent similar vulnerabilities from emerging in future versions of the software.