CVE-2017-16097 in tiny-http
Summary
by MITRE
tiny-http is a simple http server. tiny-http 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-2017-16097 affects tiny-http, a lightweight http server implementation that has been widely adopted for its simplicity and minimal resource consumption. This particular flaw represents a critical security weakness that directly impacts the server's ability to properly validate and sanitize incoming URL requests. The vulnerability stems from insufficient input validation mechanisms within the http request processing pipeline, specifically in how the server handles path components that contain relative navigation sequences.
The technical implementation flaw manifests when the tiny-http server fails to adequately sanitize url paths before serving requested resources from the filesystem. An attacker can exploit this weakness by crafting malicious requests that include directory traversal sequences such as "../" within the url path. When the server processes these requests, it does not properly validate the path components, allowing the traversal mechanism to navigate beyond the intended document root directory. This creates an opportunity for unauthorized file system access, potentially enabling attackers to read sensitive files, execute arbitrary code, or gain complete system compromise depending on the server's configuration and privileges.
The operational impact of this vulnerability extends far beyond simple information disclosure, as it fundamentally undermines the server's security boundaries and file system isolation. Attackers can leverage this vulnerability to access configuration files, application source code, database credentials, and other sensitive data that should remain protected within the server's designated directory structure. The vulnerability is particularly dangerous in environments where the http server runs with elevated privileges or where sensitive data is stored in predictable locations relative to the web root. This issue 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 attack vector aligns with techniques described in the MITRE ATT&CK framework under the T1059.007 sub-technique for command and scripting interpreter, as the vulnerability enables arbitrary file access that can lead to further exploitation.
Mitigation strategies for CVE-2017-16097 should prioritize immediate patching of the tiny-http library to version 0.6.1 or later, which includes proper path sanitization and validation mechanisms. Organizations should implement robust input validation at multiple layers, including application-level request filtering and web application firewall rules that can detect and block suspicious path traversal sequences. The server configuration should enforce strict directory traversal restrictions and implement proper access controls that limit file system access to only necessary resources. Additional defensive measures include deploying monitoring systems to detect unusual file access patterns and implementing principle of least privilege for the http server processes, ensuring they operate with minimal required permissions. Network segmentation and intrusion detection systems should also be configured to alert on suspicious url patterns containing directory traversal sequences. Regular security assessments and penetration testing should verify that path traversal vulnerabilities have been properly addressed and that no similar weaknesses exist in related components or applications that might provide alternative attack vectors.