CVE-2006-1775 in phpBB
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in phpBB 2.0.19 allow remote attackers to inject arbitrary web script or HTML via the (1) Site Description field in (a) admin_board.php, the (2) Group name and (3) Group description fields in (b) admin_groups.php and (c) groupcp.php, the (4) Theme Name field in (d) admin_styles.php, and the (5) Rank Title field in (e) admin_ranks.php. NOTE: the profile.php/Current password vector is already covered by CVE-2006-1603.
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Analysis
by VulDB Data Team • 07/24/2018
The vulnerability identified as CVE-2006-1775 represents a critical cross-site scripting weakness affecting phpBB version 2.0.19, a widely deployed open-source bulletin board system that serves as a foundational component for online discussion platforms. This vulnerability manifests across multiple administrative interfaces within the phpBB administration control panel, creating a significant attack surface that could be exploited by remote threat actors to inject malicious web scripts and HTML content into the application's web interface. The flaw specifically targets several key administrative input fields that are used to configure and manage forum elements, including site descriptions, group parameters, theme configurations, and rank titles, all of which are processed without adequate sanitization or output encoding mechanisms.
The technical exploitation of this vulnerability occurs through the manipulation of input fields within phpBB's administrative interfaces, where user-supplied data is directly incorporated into web responses without proper validation or encoding. When administrators or users interact with these vulnerable fields, the malicious content becomes part of the dynamic web page output, creating persistent XSS vectors that can execute in the context of other users' browsers. The vulnerability spans multiple files including admin_board.php, admin_groups.php, groupcp.php, admin_styles.php, and admin_ranks.php, demonstrating a systemic flaw in the application's data handling architecture rather than isolated code issues. This widespread impact suggests that the underlying sanitization and output encoding mechanisms were not properly implemented across the administrative components of the application, creating a consistent pattern of insecure data processing throughout the system.
From an operational perspective, this vulnerability presents a severe risk to phpBB installations as it enables attackers to execute arbitrary scripts in the browsers of forum users, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The attack vector requires minimal privileges since it targets administrative interfaces, meaning that even basic user accounts could potentially exploit these vulnerabilities if they have access to administrative functions or if the application's access controls are compromised. The impact extends beyond simple script execution to include potential data exfiltration and privilege escalation opportunities, particularly since administrators often have elevated permissions within the forum environment. The vulnerability's persistence across multiple administrative modules indicates that the core issue lies in the application's fundamental approach to handling user input rather than isolated implementation errors, making the exploitation potential particularly concerning for large-scale deployments.
The security implications of CVE-2006-1775 align with CWE-79, which specifically addresses cross-site scripting vulnerabilities in software applications. This classification emphasizes the fundamental flaw in input validation and output encoding practices that should be implemented at all levels of application development. The vulnerability also relates to ATT&CK technique T1566, which covers social engineering attacks through malicious content delivery, as the XSS vectors could be used to deliver malicious payloads that exploit user trust in legitimate forum applications. Organizations running vulnerable phpBB installations face significant risks including unauthorized access to administrative functions, data compromise, and potential full system compromise if attackers can leverage the XSS vulnerabilities to establish persistent access. The vulnerability's impact is amplified by the fact that many phpBB installations are used for sensitive discussions and may contain confidential information, making the potential for data breaches and unauthorized access particularly severe.
Mitigation strategies for this vulnerability should focus on immediate input sanitization and output encoding implementations across all administrative interfaces. The most effective approach involves implementing comprehensive data validation routines that filter and encode all user-supplied input before it is processed or stored, combined with proper output encoding that ensures any stored data is rendered safely in web contexts. Additionally, administrators should implement proper access controls and privilege separation to minimize the potential impact of successful exploitation attempts. Regular security audits of web applications should include specific checks for similar input validation weaknesses, particularly in administrative interfaces where the potential for privilege escalation exists. The vulnerability underscores the importance of implementing defense-in-depth strategies that include both input validation and output encoding mechanisms, as well as regular security testing and monitoring of web applications for similar vulnerabilities. Organizations should also consider implementing web application firewalls and content security policies to provide additional protection layers against XSS attacks, while ensuring that all phpBB installations are updated to versions that address this specific vulnerability and related security issues.