CVE-2004-0730 in phpBB
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in PhpBB 2.0.8 allow remote attackers to inject arbitrary web script or HTML via (1) the cat_title parameter in index.php, (2) the faq[0][0] parameter in lang_faq.php as accessible from faq.php, or (3) the faq[0][0] parameter in lang_bbcode.php as accessible from faq.php.
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Analysis
by VulDB Data Team • 07/12/2025
The CVE-2004-0730 vulnerability represents a critical cross-site scripting flaw affecting PhpBB version 2.0.8, a widely deployed open-source bulletin board system that was prevalent in web application security landscapes during that era. This vulnerability manifests across three distinct attack vectors within the application's parameter handling mechanisms, specifically targeting the cat_title parameter in index.php and the faq[0][0] parameters in both lang_faq.php and lang_bbcode.php, all of which are accessible through the faq.php interface. The vulnerability stems from inadequate input validation and output sanitization practices within the application's core codebase, creating exploitable entry points for malicious actors to inject arbitrary web scripts or HTML content into the application's response streams.
The technical implementation of this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting vulnerabilities in software applications. The flaw occurs when user-supplied input fails to undergo proper sanitization before being rendered in web pages, allowing attackers to craft malicious payloads that execute within the context of other users' browsers. In the case of PhpBB 2.0.8, the parameters cat_title and faq[0][0] are directly incorporated into HTML output without adequate filtering or encoding, creating persistent XSS opportunities. The vulnerability's exploitation requires minimal privileges and can be executed through simple HTTP requests containing malicious script payloads, making it particularly dangerous in environments where forum administrators or users have varying levels of trust.
The operational impact of CVE-2004-0730 extends beyond simple script injection, potentially enabling attackers to perform session hijacking, defacement of forum content, data theft from authenticated users, and establishment of persistent backdoors within the affected web application. Given that PhpBB installations often served as community platforms with user registration and posting capabilities, the vulnerability could facilitate widespread compromise of user accounts and sensitive information. The attack surface is particularly concerning as these parameters are accessible through standard forum navigation paths, meaning that any user with access to the affected forum could potentially become a vector for XSS attacks against other forum participants. This vulnerability also aligns with ATT&CK technique T1566, specifically targeting the initial access phase through malicious web content delivery.
Mitigation strategies for CVE-2004-0730 should prioritize immediate application updates to PhpBB 2.0.9 or later versions, which contain patches addressing the specific input validation gaps. Organizations should implement comprehensive input sanitization measures, including HTML entity encoding for all user-supplied content and strict parameter validation. Additionally, deployment of web application firewalls and content security policies can provide additional defense-in-depth layers. Security teams should conduct thorough code reviews focusing on input handling patterns and implement automated scanning tools to identify similar vulnerabilities in other applications. The vulnerability demonstrates the critical importance of maintaining current software versions and implementing proper security practices in open-source software deployments, as the attack vectors remain relevant for understanding modern web application security principles and the persistent nature of XSS vulnerabilities in legacy systems.