CVE-2017-16192 in getcityapi.yoehoehne
Summary
by MITRE
getcityapi.yoehoehne is a web server. getcityapi.yoehoehne 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-2017-16192 affects getcityapi.yoehoehne, a web server implementation that fails to properly validate user input in URL parameters. This directory traversal flaw allows malicious actors to access arbitrary files on the underlying filesystem by manipulating URL paths through the use of relative path traversal sequences such as "../". The vulnerability stems from insufficient input sanitization and validation mechanisms within the web server's request handling process, creating an exploitable condition that directly compromises the server's file system security boundaries.
This security weakness represents a classic example of a directory traversal vulnerability that aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory. The flaw operates at the application layer where user-supplied data is not adequately filtered or validated before being processed by the web server's file system operations. Attackers can leverage this vulnerability to access sensitive files including configuration data, source code, database files, and other system resources that should remain protected from unauthorized access. The impact extends beyond simple information disclosure to potentially enable further exploitation through the access to system files that may contain credentials, encryption keys, or other critical system components.
The operational impact of this vulnerability is significant as it provides attackers with the ability to perform reconnaissance and potentially escalate privileges within the affected system. Once an attacker gains access to the file system through directory traversal, they can examine the server's configuration files to identify potential further vulnerabilities, access application source code to understand system architecture, or retrieve sensitive data stored in configuration files. The vulnerability's exploitation does not require authentication, making it particularly dangerous as it can be exploited by anyone who can access the web server. This type of vulnerability is categorized under the ATT&CK technique T1083 (File and Directory Discovery) and may enable additional techniques such as T1005 (Data from Local System) and T1078 (Valid Accounts) if the accessed files contain credential information.
Mitigation strategies for this vulnerability involve implementing proper input validation and sanitization mechanisms within the web server's request processing pipeline. Organizations should ensure that all user-supplied input is validated against a strict whitelist of acceptable characters and patterns, with special attention to path traversal sequences such as "../", "..\", and similar constructs. The web server should be configured to reject any requests containing these patterns or to normalize all paths before processing file system operations. Additionally, implementing proper access controls and privilege separation can limit the damage from successful exploitation attempts. Regular security testing including penetration testing and vulnerability scanning should be conducted to identify and remediate similar issues within the application's codebase. The implementation of a web application firewall can also provide an additional layer of protection against such attacks by monitoring and filtering HTTP requests for known malicious patterns and sequences.