CVE-2005-2401 in PHP-Fusion
Summary
by MITRE
PHP-Fusion allows remote attackers to inject arbitrary Cascading Style Sheets (CSS) via the BBCode color tag.
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Analysis
by VulDB Data Team • 06/08/2019
The vulnerability described in CVE-2005-2401 represents a classic cross-site scripting weakness in the PHP-Fusion content management system that emerged during a period when web application security was rapidly evolving. This particular flaw resides in the BBCode parsing functionality of the system, specifically within how the color tag is processed and rendered. The vulnerability allows remote attackers to inject malicious CSS code through the color tag functionality, which is a fundamental component of the BBCode markup language used for formatting content within the CMS.
The technical mechanism behind this vulnerability involves improper input validation and output encoding within the PHP-Fusion application's BBCode processor. When users submit content containing BBCode color tags, the system fails to adequately sanitize the input parameters before rendering them in the final HTML output. This inadequate sanitization creates an opportunity for attackers to inject malicious CSS code that gets executed in the browsers of other users who view the affected content. The vulnerability specifically targets the color tag functionality which is commonly used to format text within forum posts, comments, and other user-generated content areas.
The operational impact of this vulnerability extends beyond simple visual disruption as it can enable sophisticated attack vectors including but not limited to session hijacking, credential theft, and redirection to malicious websites. When an attacker successfully injects CSS code through the color tag, they can potentially manipulate the user interface in ways that facilitate further exploitation. The vulnerability affects all versions of PHP-Fusion that were vulnerable to this specific input sanitization flaw, making it particularly dangerous given the widespread adoption of the CMS at the time. Users with administrative privileges could leverage this vulnerability to gain deeper access to the system through the injection of malicious code that might interact with other system components.
From a cybersecurity perspective, this vulnerability aligns with CWE-79 which describes Cross-Site Scripting flaws in web applications. The attack pattern closely follows the techniques outlined in the ATT&CK framework under the T1059.007 sub-technique for Scripting, where adversaries use web-based scripting to execute malicious code. The vulnerability also demonstrates characteristics of T1566 related to credential access through social engineering, as attackers could use the injected CSS to manipulate user interfaces in ways that trick victims into revealing sensitive information. Organizations using PHP-Fusion during this time period faced significant risk of compromise, particularly in environments where user-generated content was common and proper input validation was not implemented.
Mitigation strategies for this vulnerability required immediate patching of the affected PHP-Fusion versions, implementation of proper input sanitization routines, and deployment of web application firewalls to monitor and block suspicious CSS injection attempts. The fix typically involved enhancing the BBCode parser to properly escape or validate CSS attributes before rendering them in the final output, ensuring that any user-supplied CSS code was properly encoded to prevent execution. Additionally, implementing proper content security policies and regular security audits of input processing functions became essential practices for preventing similar vulnerabilities from emerging in the future. Organizations needed to conduct comprehensive security assessments of their web applications and implement proper output encoding mechanisms to protect against similar injection attacks.