CVE-2004-1809 in phpBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in phpBB 2.0.6d and earlier allows remote attackers to inject arbitrary web script or HTML via the (1) postdays parameter to viewtopic.php or (2) topicdays parameter to viewforum.php.
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Analysis
by VulDB Data Team • 05/20/2019
The vulnerability identified as CVE-2004-1809 represents a critical cross-site scripting flaw within the phpBB bulletin board system version 2.0.6d and earlier releases. This vulnerability resides in the web application's handling of user-supplied input parameters, specifically targeting the postdays parameter in viewtopic.php and the topicdays parameter in viewforum.php. The flaw enables remote attackers to execute malicious scripts within the context of a victim's browser session, potentially compromising user security and data integrity. This type of vulnerability falls under the Common Weakness Enumeration category CWE-79, which defines improper neutralization of input during web page generation, commonly known as cross-site scripting. The vulnerability exists due to inadequate sanitization of user input before it is rendered back to users within the web application interface.
The technical exploitation of this vulnerability occurs when an attacker crafts malicious input containing script code within the affected parameters and submits it to the vulnerable phpBB installation. When the application processes these parameters without proper validation or encoding, the malicious code becomes embedded within the generated HTML output. Upon subsequent page loading by authenticated users or visitors, the malicious script executes in their browser context, potentially stealing session cookies, redirecting users to malicious sites, or performing actions on behalf of the victim. The attack vector is particularly dangerous because it leverages legitimate application functionality to deliver malicious payloads, making detection more challenging for security systems and users alike. This vulnerability directly impacts the web application's security model by undermining the principle of input validation and output encoding that are fundamental to preventing XSS attacks.
The operational impact of CVE-2004-1809 extends beyond simple script execution, as it can enable more sophisticated attacks within the phpBB environment. Attackers can leverage this vulnerability to manipulate forum content, steal user credentials, or establish persistent access through session hijacking. The vulnerability affects all users who interact with the forum, including administrators and regular members, potentially compromising the entire community platform. Given that phpBB was widely deployed in various web environments, the potential attack surface was significant, with numerous organizations and individuals exposed to this vulnerability. The vulnerability's persistence in the application's codebase for several years indicates a fundamental flaw in the input processing logic that required immediate remediation to prevent exploitation. Organizations using affected versions faced potential data breaches and service disruption risks, as the vulnerability could be exploited to manipulate forum data or compromise user privacy.
Mitigation strategies for this vulnerability involve immediate application updates to versions that address the XSS flaw, typically through proper input validation and output encoding implementations. System administrators should implement comprehensive input sanitization measures, including the use of secure coding practices such as HTML entity encoding for all user-supplied content before rendering. The implementation of Content Security Policy headers can provide additional defense-in-depth measures to prevent script execution in compromised contexts. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in web applications, particularly those involving user input processing. Organizations should also consider implementing web application firewalls to detect and block malicious input patterns targeting known XSS vulnerabilities. The remediation process should include thorough testing of all input parameters to ensure proper validation and encoding, following security best practices established by the Open Web Application Security Project and other industry standards. This vulnerability serves as a critical reminder of the importance of maintaining up-to-date software components and implementing robust input validation mechanisms to prevent exploitation of common web application flaws.