CVE-2017-16143 in commentapp.stetsonwood
Summary
by MITRE
commentapp.stetsonwood is an http server. commentapp.stetsonwood 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-2017-16143 affects commentapp.stetsonwood, an http server implementation that suffers from a critical directory traversal flaw. This issue stems from inadequate input validation within the server's url parsing mechanism, allowing remote attackers to manipulate file paths through crafted url parameters containing directory traversal sequences. The vulnerability manifests when the application fails to properly sanitize user-supplied input before using it to construct file system paths, creating an exploitable condition that enables unauthorized access to the underlying operating system's file system.
This directory traversal vulnerability represents a classic security flaw that maps directly to CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory. The attack vector exploits the server's failure to properly validate and sanitize url parameters, allowing malicious actors to navigate beyond the intended document root directory. When "../" sequences are injected into the url, they can be interpreted by the server's file system operations to traverse up directory levels, potentially accessing sensitive files, configuration data, or system resources that should remain protected from external access.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with arbitrary file system access capabilities that can lead to complete system compromise. An attacker could potentially read sensitive files such as configuration databases, application source code, user credentials, or system binaries, depending on the server's file permissions and the application's data exposure. This vulnerability aligns with ATT&CK technique T1083, which covers directory and file permissions enumeration, and T1566, covering credential access through various attack vectors. The potential for data exfiltration, system reconnaissance, and further attack progression makes this vulnerability particularly dangerous in production environments.
Mitigation strategies for CVE-2017-16143 should focus on implementing robust input validation and sanitization mechanisms within the http server's url processing pipeline. The most effective approach involves implementing proper path normalization and validation that rejects or strips directory traversal sequences from user input before any file system operations occur. Organizations should also consider implementing secure coding practices that enforce strict access controls and privilege separation, ensuring that the application operates with minimal necessary permissions. Additionally, deploying web application firewalls and implementing proper network segmentation can provide additional layers of protection against exploitation attempts. Regular security audits and penetration testing should be conducted to identify and remediate similar vulnerabilities across the entire application stack, as directory traversal issues often occur in multiple components of web applications and can be exploited through various entry points.