CVE-2005-0259 in phpBB
Summary
by MITRE
phpBB 2.0.11, and possibly other versions, with remote avatars and avatar uploading enabled, allows local users to read arbitrary files by providing both a local and remote location for an avatar, then modifying the "Upload Avatar from a URL:" field to reference the target file.
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Analysis
by VulDB Data Team • 07/17/2024
The vulnerability described in CVE-2005-0259 represents a critical file inclusion flaw in phpBB version 2.0.11 and potentially other versions that enables local users to access arbitrary files through manipulated avatar upload functionality. This issue arises from inadequate input validation and sanitization within the avatar handling mechanism, specifically when both local and remote avatar options are enabled. The vulnerability stems from the application's failure to properly validate user-provided URLs and file paths, creating a pathway for unauthorized file access that could expose sensitive system information.
The technical implementation of this vulnerability exploits the interaction between local file system access and remote URL handling within phpBB's avatar management system. When users enable both local avatar uploads and remote avatar functionality, the application processes user input without sufficient sanitization measures. Attackers can manipulate the "Upload Avatar from a URL:" field to reference local system files that should normally be inaccessible to regular users. This flaw operates through a path traversal or local file inclusion pattern where the application treats user-provided URLs as valid file paths, allowing access to files that reside on the same server as the phpBB installation. The vulnerability specifically affects systems where both avatar upload methods are enabled, creating a dangerous intersection of local and remote file handling capabilities.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose sensitive system files including configuration files, database credentials, and other system resources that could aid in further exploitation. Attackers could leverage this vulnerability to gain access to phpBB's configuration files, which often contain database connection details, administrator credentials, or other sensitive information. The flaw represents a significant security risk in web applications that allow user-generated content with file upload capabilities, as it effectively bypasses normal file system access controls and permissions. This vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and CWE-94, which addresses the execution of arbitrary code through code injection. The attack vector demonstrates a classic case of insufficient input validation that enables path traversal attacks, allowing unauthorized file access through manipulated user input fields.
Organizations running affected phpBB installations should implement immediate mitigations including disabling either local avatar uploads or remote avatar functionality, depending on their operational requirements. The most effective approach involves restricting the avatar upload capabilities to only one method at a time, preventing the dangerous intersection that enables this vulnerability. System administrators should also consider implementing input validation filters that prevent the use of local file paths in URL fields and ensure that all user-provided URLs are properly sanitized before processing. Additionally, the application should enforce strict file path validation that prevents access to system directories and ensures that only authorized file types can be uploaded. This vulnerability highlights the importance of proper input validation and access control mechanisms in web applications, particularly those handling user-generated content. The issue demonstrates how seemingly innocuous features like avatar uploads can become security risks when not properly implemented with adequate validation and sanitization measures, emphasizing the need for comprehensive security testing and code review practices.
This vulnerability also relates to ATT&CK technique T1083, which covers directory and file system discovery, and T1566, which addresses credential access through various attack vectors. The flaw enables attackers to perform unauthorized file system reconnaissance and access sensitive information that could lead to further compromise of the system. Organizations should also consider implementing web application firewalls and monitoring for suspicious file access patterns that could indicate exploitation attempts. Regular security updates and patches should be applied to ensure that known vulnerabilities like CVE-2005-0259 are addressed through proper remediation measures. The vulnerability serves as a reminder of the critical importance of validating all user input and implementing proper access controls in web applications, particularly those that handle file system operations and user-generated content.