CVE-2017-16180 in serverabc
Summary
by MITRE
serverabc is a static file server. serverabc 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-2017-16180 affects serverabc, a static file server implementation that suffers from a critical directory traversal flaw. This issue allows attackers to access arbitrary files on the server's filesystem by manipulating URL parameters through the strategic insertion of "../" sequences. The vulnerability stems from insufficient input validation and improper path handling within the server's file access mechanisms. When a user submits a request containing directory traversal sequences, the server fails to properly sanitize the input before resolving the requested file path, creating an opportunity for unauthorized access to sensitive system resources.
This directory traversal vulnerability represents a fundamental flaw in the server's security architecture and aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory. The issue enables attackers to bypass normal access controls and potentially retrieve confidential files, configuration data, or system binaries that should remain protected. The exploitation technique leverages the universal nature of directory traversal attacks, making it particularly dangerous as it can be applied across various operating systems and file server implementations. The vulnerability essentially allows an attacker to navigate upward through the directory structure and access files outside of the intended document root, potentially leading to complete system compromise.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to access sensitive system files, user data, and potentially execute malicious code if the server has access to writable directories. Attackers can exploit this weakness to access configuration files that may contain database credentials, API keys, or other sensitive authentication information. The vulnerability's severity increases when the server runs with elevated privileges, as it could allow attackers to read system files, access user accounts, or potentially escalate their privileges further. This type of vulnerability is particularly concerning in environments where static file servers are used to serve content to untrusted users without proper access controls.
Mitigation strategies for CVE-2017-16180 should focus on implementing robust input validation and sanitization mechanisms within the server's file access routines. The most effective immediate fix involves implementing proper path normalization and validation that rejects or removes directory traversal sequences from user input before processing file requests. Security measures should include validating all file paths against a whitelist of allowed directories, implementing proper access controls, and ensuring that the server operates with minimal necessary privileges. Organizations should also consider implementing web application firewalls that can detect and block directory traversal attempts, as well as regular security scanning to identify similar vulnerabilities in other applications. The remediation process should follow established security practices outlined in the ATT&CK framework under the T1083 technique for discovering files and directories, ensuring that defensive measures are comprehensive and layered to prevent similar vulnerabilities from being exploited in the future.