CVE-2005-1896 in FlatNuke
Summary
by MITRE
Directory traversal vulnerability in thumb.php in FlatNuke 2.5.3 allows remote attackers to read arbitrary images or obtain the installation path via the image parameter.
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Analysis
by VulDB Data Team • 07/09/2018
The vulnerability identified as CVE-2005-1896 represents a critical directory traversal flaw within the FlatNuke content management system version 2.5.3, specifically affecting the thumb.php script. This vulnerability resides in the handling of user-supplied input through the image parameter, which lacks proper validation and sanitization mechanisms. The flaw allows malicious actors to manipulate file path references and access arbitrary files on the server, potentially exposing sensitive system information or unauthorized content. Directory traversal vulnerabilities of this nature fall under the CWE-22 category, which classifies improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. These attacks exploit insufficient input validation to access files and directories outside the intended scope, often leading to information disclosure, system compromise, or unauthorized access to sensitive resources.
The technical implementation of this vulnerability occurs when the thumb.php script processes the image parameter without adequate filtering of special characters or path sequences such as "../" or "..\" that would normally be used to navigate up directory levels. Attackers can exploit this weakness by crafting malicious URLs that include these traversal sequences, enabling them to bypass normal access controls and retrieve files from locations outside the intended image directory. The vulnerability specifically affects the image processing functionality of FlatNuke, where user input directly influences file system operations. This type of attack vector aligns with the ATT&CK technique T1083, which covers the discovery of system information through techniques that allow adversaries to enumerate file systems and directories. The exploitation process typically involves sending a crafted HTTP request containing the malicious image parameter, which then gets processed by the vulnerable script and results in unauthorized file access.
The operational impact of CVE-2005-1896 extends beyond simple information disclosure, as it can potentially expose the complete installation path of the FlatNuke system, providing attackers with valuable reconnaissance information for further exploitation attempts. This exposure of installation paths can aid in identifying system configuration details, potentially revealing version information, file locations, and directory structures that could be leveraged for additional attacks. The vulnerability also poses risks to image data integrity, as attackers might be able to access or potentially overwrite sensitive image files stored on the server. Organizations running FlatNuke 2.5.3 are particularly vulnerable to this attack, as the flaw exists in a widely used content management system that may be deployed in various environments without proper security hardening. The attack surface is broad since the vulnerability affects the core image processing functionality, making it a prime target for automated exploitation tools. Security professionals should note that this vulnerability demonstrates the importance of input validation and the principle of least privilege in file system operations, where applications should never trust user input and should always validate and sanitize all external data before processing.
Mitigation strategies for CVE-2005-1896 should focus on implementing proper input validation and sanitization measures within the thumb.php script. The most effective approach involves validating the image parameter against a whitelist of allowed file paths or implementing proper path normalization techniques that prevent traversal sequences from being processed. Organizations should also consider implementing proper access controls and file permissions that restrict the web application's ability to access sensitive directories. Additionally, the recommended remediation includes upgrading to a patched version of FlatNuke or implementing a web application firewall rule that blocks malicious path traversal attempts. Security monitoring should include logging and alerting on suspicious file access patterns, particularly those involving directory traversal sequences. The vulnerability also underscores the importance of regular security audits and penetration testing to identify similar flaws in other components of the application stack, as directory traversal vulnerabilities are commonly found in legacy applications and can serve as initial footholds for more extensive attacks. Organizations should also implement proper security configuration management to ensure that web applications are not running with unnecessary privileges and that file system access is appropriately restricted.