CVE-2017-16092 in Sencisho
Summary
by MITRE
Sencisho is a simple http server for local development. Sencisho 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 • 02/15/2020
The vulnerability identified as CVE-2017-16092 affects Sencisho, a lightweight http server designed for local development environments. This tool, while intended to simplify web development workflows, contains a critical security flaw that stems from inadequate input validation mechanisms. The vulnerability manifests as a directory traversal issue that allows remote attackers to access arbitrary files on the server's filesystem through carefully crafted URL requests. The flaw specifically occurs when the application fails to properly sanitize user-supplied input that contains directory traversal sequences, enabling malicious actors to navigate beyond the intended document root directory.
This directory traversal vulnerability represents a fundamental flaw in the application's request processing logic, where the server does not adequately validate or filter path components submitted by clients. When a user includes "../" sequences in the URL path, the server processes these traversal commands without proper sanitization, allowing access to files outside the designated web root directory. The vulnerability is classified under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. This weakness enables attackers to access sensitive files including configuration files, source code, system credentials, and other confidential data that should remain isolated from external access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the ability to execute arbitrary file access patterns against the underlying filesystem. An attacker could potentially retrieve sensitive configuration files containing database credentials, application secrets, or system passwords that are stored in accessible locations. Additionally, the vulnerability could enable further exploitation through the access to system files, log files, or other resources that might contain useful information for privilege escalation or additional attack vectors. The severity of this issue is compounded by the fact that Sencisho is typically used in development environments where sensitive data might be present, and the server may have elevated privileges or access to confidential information.
Mitigation strategies for this vulnerability must address the core issue of input validation and path sanitization within the application's request handling mechanism. The most effective approach involves implementing strict input validation that filters out or rejects directory traversal sequences before processing any file system operations. This can be achieved through proper path normalization techniques that ensure all file access operations occur within the designated document root directory. Organizations should also consider implementing the principle of least privilege by running the Sencisho server with minimal necessary permissions and avoiding the use of the tool in production environments. Security best practices recommend that development servers should not be exposed to untrusted networks and should only be accessible from local development machines. Furthermore, regular security audits and input validation testing should be implemented to identify similar vulnerabilities in other components of the development infrastructure, aligning with ATT&CK technique T1059 which covers command and script injection, and T1083 which addresses file and directory discovery. The vulnerability highlights the importance of secure coding practices and input validation in web applications, particularly in development tools that may inadvertently expose sensitive system resources due to insufficient security controls.