CVE-2017-16175 in ewgaddis.lab6
Summary
by MITRE
ewgaddis.lab6 is a file server. ewgaddis.lab6 is vulnerable to a directory traversal issue, giving an attacker access to the filesystem by placing "../" in the url.
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Analysis
by VulDB Data Team • 02/16/2020
The vulnerability identified as CVE-2017-16175 affects ewgaddis.lab6, a file server implementation that demonstrates a critical directory traversal flaw in its web interface. This weakness allows remote attackers to access arbitrary files on the server's filesystem by manipulating URL parameters through the strategic insertion of directory traversal sequences such as "../". The vulnerability stems from insufficient input validation and sanitization within the application's file handling mechanisms, particularly in how it processes user-supplied path information. When the application receives a request containing traversal sequences, it fails to properly validate or sanitize the input before using it to construct file paths, thereby enabling unauthorized access to files outside the intended directory structure.
The technical nature of this vulnerability aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This flaw represents a fundamental security weakness in the application's input handling and access control mechanisms, allowing attackers to bypass normal file access restrictions. The vulnerability exists at the application layer and can be exploited through HTTP requests that manipulate URL parameters to navigate through the file system hierarchy. Attackers can leverage this weakness to access sensitive files including configuration files, source code, database files, and other system resources that should remain protected from unauthorized access.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with the ability to read arbitrary files on the affected server. This could potentially lead to information disclosure of sensitive data, including but not limited to database credentials, application configuration files, user data, and system files. The vulnerability enables attackers to escalate their privileges and potentially gain deeper access to the underlying system, as access to configuration files may reveal database connection strings, API keys, or other credentials that could be used for further exploitation. Additionally, the ability to read source code files could expose implementation details that attackers might use to identify additional vulnerabilities or develop more sophisticated attack vectors.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and sanitization mechanisms within the application. The most effective approach involves implementing proper path validation that rejects or removes directory traversal sequences from user input before processing. This can be achieved through the use of allowlists that define acceptable file paths or by implementing strict input filtering that prevents the use of special characters such as ".." in file path parameters. The application should also employ proper access controls and privilege separation to ensure that even if traversal attacks succeed, attackers cannot access files beyond the intended directory boundaries. Additionally, implementing proper logging and monitoring of file access patterns can help detect and respond to potential exploitation attempts. Organizations should also consider implementing web application firewalls and security headers to add additional layers of protection against such attacks. The remediation process should include comprehensive testing to ensure that all input paths are properly validated and that the application behaves correctly when encountering potentially malicious input sequences.
This vulnerability demonstrates the critical importance of input validation in web applications and aligns with several ATT&CK techniques including T1083 (File and Directory Discovery) and T1566 (Phishing). The attack pattern represents a classic example of how insufficient validation of user input can lead to privilege escalation and information disclosure, making it a prime target for threat actors seeking to compromise web applications and their underlying systems.