CVE-2017-16218 in dgard8.lab6
Summary
by MITRE
dgard8.lab6 is a static file server. dgard8.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-2017-16218 affects dgard8.lab6, a static file server implementation that suffers from a critical directory traversal flaw. This weakness allows remote attackers to access arbitrary files on the underlying filesystem by manipulating URL parameters through the strategic insertion of "../" sequences. The vulnerability represents a classic path traversal issue that has been documented in numerous security frameworks and standards, including CWE-22 which specifically addresses improper limitation of a pathname to a restricted directory. The flaw exists because the application fails to properly validate or sanitize user-supplied input that is used to construct file paths, creating an opportunity for attackers to navigate beyond the intended directory boundaries.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing directory traversal sequences that bypass the server's intended file access controls. When the static file server processes these requests, it interprets the "../" sequences as commands to move up the directory hierarchy, potentially allowing access to sensitive system files, configuration data, or other restricted resources that should remain protected from unauthorized access. This type of vulnerability is particularly dangerous in static file servers because these systems often serve files directly from the filesystem without adequate input validation, making them prime targets for path traversal attacks that align with ATT&CK technique T1083 for discovering files and directories.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially lead to complete system compromise depending on the permissions of the file server process and the sensitivity of accessible files. An attacker could potentially access system configuration files, user credentials, application source code, or other sensitive data that might reveal additional attack vectors or facilitate further compromise. The vulnerability affects the fundamental security principle of least privilege, as it allows unauthorized access to resources that should be restricted to legitimate users or processes. Organizations running affected versions of dgard8.lab6 face significant risk of data breaches, regulatory compliance violations, and potential system infiltration that could result in broader network compromise.
Mitigation strategies for this vulnerability should include immediate implementation of proper input validation and sanitization for all user-supplied path parameters. The static file server implementation must be updated to reject or normalize directory traversal sequences before processing file requests, ensuring that all paths are validated against a whitelist of acceptable directories. Organizations should also consider implementing web application firewalls that can detect and block suspicious path traversal patterns, as well as conducting comprehensive security reviews of all file serving components to identify similar vulnerabilities. Additionally, system administrators should ensure that the file server process runs with minimal required privileges and that sensitive files are properly secured through operating system permissions and access controls. The remediation approach should follow security best practices outlined in industry standards such as NIST SP 800-53 and ISO/IEC 27001, which emphasize the importance of input validation and access control mechanisms to prevent unauthorized system access.