CVE-2017-16095 in serverliujiayi1
Summary
by MITRE
serverliujiayi1 is a simple http server. serverliujiayi1 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-2017-16095 affects serverliujiayi1, a straightforward http server implementation that demonstrates a critical directory traversal flaw in its file handling mechanism. This weakness allows malicious actors to access arbitrary files on the server's filesystem by manipulating URL parameters through the strategic insertion of "../" sequences. The vulnerability represents a fundamental failure in input validation and path resolution within the server's request processing pipeline.
The technical root cause of this vulnerability aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks. When the server processes incoming requests, it fails to properly sanitize or validate the requested file paths, allowing attackers to navigate upward through the directory structure using relative path references. This occurs because the server does not implement proper input filtering or canonicalization of file paths before attempting to access files on the underlying filesystem. The vulnerability exists at the application layer and can be exploited through HTTP GET requests that contain malicious path sequences.
The operational impact of this directory traversal vulnerability is severe and multifaceted. An attacker with knowledge of the server's directory structure can potentially access sensitive files including configuration files, database files, application source code, and system credentials stored in accessible locations. This exposure can lead to complete system compromise, data exfiltration, and potential lateral movement within network environments. The vulnerability affects the confidentiality and integrity of the system as it allows unauthorized access to potentially privileged files and directories that should remain protected from external inspection. Additionally, this flaw can be leveraged as a reconnaissance tool to gather information about the server environment and identify other potential vulnerabilities.
This vulnerability maps to several techniques documented in the MITRE ATT&CK framework, particularly those related to credential access and defense evasion. The ability to traverse directories and access sensitive files aligns with techniques such as "T1078 - Valid Accounts" and "T1005 - Data from Local System" where attackers can obtain credentials and sensitive information from compromised systems. The vulnerability also supports "T1083 - File and Directory Discovery" as attackers can enumerate the filesystem to identify valuable targets. Organizations should implement immediate mitigations including input validation, proper path canonicalization, and restricting file access permissions. The most effective remediation involves implementing strict input validation that filters out or rejects any path components containing "../" sequences and ensuring that all file access operations occur within a designated safe directory or chroot environment. Additionally, regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other applications and services within the organization's attack surface.