CVE-2017-16184 in scott-blanch-weather-app
Summary
by MITRE
scott-blanch-weather-app is a sample Node.js app using Express 4. scott-blanch-weather-app 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-2017-16184 affects the scott-blanch-weather-app, a sample Node.js application that utilizes Express 4 framework. This application demonstrates a critical directory traversal flaw that exposes sensitive system information and potentially allows unauthorized file access. The vulnerability stems from improper input validation within the application's file serving mechanism, where user-supplied URL parameters are not adequately sanitized before being processed.
The technical flaw manifests when an attacker crafts malicious URLs containing directory traversal sequences such as "../" which can navigate outside the intended application directory structure. This allows the application to serve files from arbitrary locations on the filesystem, potentially exposing sensitive configuration files, source code, database credentials, or other confidential information. The vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The issue occurs because the application fails to properly validate or sanitize file paths before accessing them, creating an opportunity for attackers to manipulate the application's file system access patterns.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to execute further malicious activities within the compromised system. An attacker could potentially access system configuration files, application secrets, or even gain access to other parts of the file system that should remain protected. This vulnerability particularly affects applications running on Unix-like systems where directory traversal techniques are most effective. The attack vector is straightforward and can be exploited through simple URL manipulation, making it accessible to attackers with minimal technical expertise. The vulnerability also aligns with ATT&CK technique T1083, which covers the discovery of system information through directory listing and file enumeration activities.
Mitigation strategies for this vulnerability involve implementing proper input validation and sanitization mechanisms within the application code. Developers should ensure that all file paths are validated against a whitelist of acceptable directories or implement proper path normalization techniques that prevent traversal sequences from being processed. The Express framework provides built-in mechanisms for secure file serving that should be utilized instead of custom implementations that do not properly validate input. Additionally, implementing proper access controls and privilege separation can limit the damage that can be caused by such vulnerabilities. The application should be configured to run with minimal required privileges and should not have access to sensitive system directories or files beyond what is necessary for its operation. Regular security code reviews and automated vulnerability scanning should be implemented to identify and remediate similar issues in other applications within the organization's portfolio.