CVE-2008-6727 in UPB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Ultimate PHP Board (UPB) 2.2.2, 2.2.1, and earlier 2.x versions allows remote attackers to inject arbitrary web script or HTML via the User-Agent HTTP header.
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Analysis
by VulDB Data Team • 11/21/2024
The CVE-2008-6727 vulnerability represents a critical cross-site scripting flaw discovered in the Ultimate PHP Board (UPB) software versions 2.2.2 and earlier. This vulnerability specifically affects the handling of HTTP headers within the web application's input validation mechanisms. The flaw exists in the way the UPB software processes the User-Agent HTTP header, which is automatically sent by web browsers and other HTTP clients during web requests. When attackers exploit this vulnerability, they can inject malicious scripts or HTML code directly through this header field, bypassing normal input sanitization measures that typically protect against such attacks.
The technical nature of this vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a code injection flaw that allows attackers to execute malicious scripts in the context of other users' browsers. The vulnerability is particularly concerning because it operates at the HTTP header level rather than through typical user input fields, making it more difficult to detect and prevent using standard web application security measures. The User-Agent header is commonly used by web applications for various purposes including browser detection, logging, and feature detection, but in this case, it becomes an attack vector that allows arbitrary code execution in the victim's browser context. This specific implementation flaw demonstrates poor input validation and sanitization practices within the UPB application's codebase.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, defacement of web pages, and redirection to malicious sites. When a victim's browser makes a request to a compromised UPB installation, the malicious script injected through the User-Agent header executes in the victim's browser context, potentially compromising their session cookies, personal information, or even allowing full control of their browser session. The vulnerability is particularly dangerous because it requires no user interaction beyond visiting a website that uses the vulnerable UPB software, making it a passive attack vector that can affect any user who accesses the compromised site. The attack can be executed by any remote attacker who can control the User-Agent header, which is easily achievable through various HTTP request manipulation techniques.
Mitigation strategies for this vulnerability require immediate attention through software updates and patches provided by the UPB developers, as well as implementing proper input validation and sanitization measures at the application level. Organizations should ensure that all HTTP headers, particularly User-Agent, are properly escaped and validated before being processed or displayed within the web application. Security measures should include implementing Content Security Policy headers to limit script execution, using proper output encoding for all dynamic content, and implementing web application firewalls to detect and block suspicious User-Agent patterns. The vulnerability also highlights the importance of following secure coding practices as outlined in the OWASP Top Ten and MITRE ATT&CK framework, specifically addressing the techniques related to command injection and client-side attacks. Regular security assessments and code reviews should be conducted to identify similar vulnerabilities in other applications and ensure that all input sources are properly validated and sanitized to prevent similar XSS attack vectors from being exploited in the future.