CVE-2006-2143 in TextFileBB
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in TextFileBB 1.0.16 allow remote attackers to inject arbitrary web script or HTML via Javascript events such as "onmouseover" in the (1) color, (2) size, or (3) url bbcode tags.
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Analysis
by VulDB Data Team • 07/25/2018
The vulnerability identified as CVE-2006-2143 represents a critical cross-site scripting flaw within TextFileBB version 1.0.16, a web-based bulletin board system that was widely used for community forums and discussion platforms. This vulnerability specifically affects the bbcode parsing functionality of the application, which is designed to convert simplified markup language into HTML for display on web pages. The flaw allows remote attackers to inject malicious JavaScript code through carefully crafted input that exploits the application's insufficient sanitization of user-supplied data within specific bbcode tags.
The technical implementation of this vulnerability occurs within the text processing pipeline of TextFileBB where user input is parsed and converted into HTML output. Attackers can exploit three distinct bbcode tags - color, size, and url - by injecting javascript event handlers such as onmouseover, onclick, or other DOM events directly into the parameter values of these tags. When other users view the affected posts, the injected javascript code executes in their browsers within the context of the vulnerable forum's domain, creating a persistent cross-site scripting vector that can be leveraged for various malicious purposes including session hijacking, credential theft, or redirection to malicious sites.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it provides attackers with a persistent foothold within the forum environment. The vulnerability affects all users who view posts containing the malicious code, creating a chain reaction where each compromised post can serve as a vector to spread the attack to other forum participants. This makes the vulnerability particularly dangerous in community forums where users frequently interact with content posted by others, potentially enabling widespread compromise of user sessions and personal data. The attack can be executed without requiring user interaction beyond normal forum browsing activities, making it particularly stealthy and effective.
From a cybersecurity framework perspective, this vulnerability maps directly to CWE-79 Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security. The vulnerability also aligns with ATT&CK technique T1566.001 Initial Access: Phishing, as attackers can leverage the XSS vector to deliver malicious payloads that redirect users to phishing sites or harvest credentials. The attack chain typically involves an attacker posting malicious content containing javascript payloads, which then executes in the victim's browser when they view the forum post, potentially leading to session theft, data exfiltration, or further exploitation of the compromised user's privileges within the forum environment. Organizations should implement proper input validation, output encoding, and content security policies to prevent such vulnerabilities from being exploited.
The remediation approach for this vulnerability requires immediate implementation of proper input sanitization and output encoding mechanisms within the TextFileBB application. Developers must ensure that all user-supplied data entering the system is properly validated and that any javascript event handlers are stripped or encoded before being rendered as HTML. Additionally, implementing a content security policy that restricts the execution of inline javascript and limits the use of dangerous attributes like onmouseover would provide defense-in-depth against similar vulnerabilities. Regular security audits and input validation testing should be conducted to prevent similar issues from being introduced in future versions of the application, as this vulnerability demonstrates the critical importance of proper sanitization of user input in web applications.