CVE-2009-4809 in Easy File Sharing Web Server
Summary
by MITRE
Directory traversal vulnerability in thumbnail.ghp in Easy File Sharing (EFS) Web Server 4.8 allows remote attackers to read arbitrary files via a .. (dot dot) in the vfolder parameter.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2009-4809 represents a critical directory traversal flaw within the Easy File Sharing Web Server version 4.8, specifically affecting the thumbnail.ghp component. This weakness enables remote attackers to access arbitrary files on the server by manipulating the vfolder parameter through the use of .. (dot dot) sequences. The vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly restrict file path access, allowing malicious users to navigate beyond the intended directory structure and potentially access sensitive system files, configuration data, or user information stored on the server. Such directory traversal vulnerabilities are particularly dangerous as they can provide unauthorized access to critical system resources without requiring authentication or elevated privileges.
The technical implementation of this vulnerability involves the web server's insufficient validation of user-supplied input in the vfolder parameter. When a user submits a request containing .. sequences within the vfolder parameter, the server processes these inputs without proper sanitization, allowing the traversal logic to execute beyond the designated file access boundaries. This flaw directly maps to CWE-22, which categorizes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The vulnerability operates at the application layer and can be exploited through HTTP requests, making it particularly accessible to attackers who may not require physical access to the system or advanced technical skills to compromise the server's file system.
The operational impact of CVE-2009-4809 extends beyond simple unauthorized file access, potentially enabling attackers to gain sensitive information that could facilitate further exploitation. Depending on the server configuration and file permissions, successful exploitation could lead to the disclosure of system configuration files, user credentials, application source code, or other confidential data. This vulnerability can be leveraged as a stepping stone for more sophisticated attacks, including privilege escalation, system compromise, or data exfiltration. The attack vector is particularly concerning because it requires no authentication and can be executed remotely, making it a significant risk for organizations using vulnerable versions of Easy File Sharing Web Server. According to ATT&CK framework, this vulnerability aligns with T1083 (File and Directory Discovery) and T1566 (Phishing for Information) techniques, as attackers can systematically enumerate and extract valuable data from the compromised system.
Mitigation strategies for this vulnerability should focus on immediate patching of the Easy File Sharing Web Server to version 5.0 or later, which contains the necessary security fixes. Organizations should implement proper input validation and sanitization measures to prevent the acceptance of .. sequences in file path parameters. Network segmentation and access controls can help limit the exposure of vulnerable systems, while regular security audits and vulnerability assessments should be conducted to identify similar issues in other applications. Additionally, implementing web application firewalls and intrusion detection systems can provide additional layers of protection against exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper input validation and secure coding practices in web applications, particularly when handling file system operations and user-supplied data that could influence system behavior.