CVE-2018-3787 in simplehttpserver
Summary
by MITRE
Path traversal in simplehttpserver <v0.2.1 allows listing any file on the server.
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Analysis
by VulDB Data Team • 03/19/2020
The vulnerability identified as CVE-2018-3787 resides within the simplehttpserver software version 0.2.1 and earlier, presenting a critical path traversal flaw that enables unauthorized file listing across the entire server filesystem. This vulnerability stems from inadequate input validation and improper handling of file paths when processing user requests, allowing malicious actors to craft specific requests that bypass normal directory restrictions. The flaw specifically affects the server's ability to properly sanitize file path references, creating an opportunity for attackers to navigate beyond the intended document root and access arbitrary files on the system.
The technical implementation of this vulnerability involves the server's failure to properly validate and sanitize user-supplied path parameters during HTTP request processing. When users submit requests containing directory traversal sequences such as ../ or ..\, the vulnerable server fails to adequately filter or resolve these paths, allowing the underlying file system to interpret these sequences as legitimate navigation commands. This misconfiguration creates a direct pathway to the file system where attackers can enumerate directories and potentially access sensitive files including configuration data, log files, and application source code. The vulnerability operates at the application layer and can be exploited through standard HTTP GET requests without requiring authentication or specialized tools beyond basic web browsing capabilities.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with comprehensive reconnaissance capabilities and potential access to sensitive system information. An attacker can leverage this vulnerability to discover the server's directory structure, identify sensitive files such as database credentials, application configuration files, and potentially even source code repositories. The ability to list arbitrary files creates a foundation for further exploitation including privilege escalation, data exfiltration, and the identification of additional vulnerabilities within the system. This vulnerability directly violates security principles established in the CWE-22 category for Path Traversal and aligns with ATT&CK techniques related to reconnaissance and credential access through file system enumeration.
Mitigation strategies for CVE-2018-3787 should prioritize immediate software updates to versions that properly implement input validation and path sanitization. Organizations must ensure that all instances of simplehttpserver are updated to versions that properly resolve and validate file paths, implementing proper directory traversal protection mechanisms. Network-level controls including web application firewalls and intrusion prevention systems should be configured to detect and block suspicious path traversal attempts. Additionally, system administrators should implement proper access controls and file permissions to minimize the impact of any successful exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and the principle of least privilege in web application security, as recommended by industry standards including those outlined in the OWASP Top Ten and NIST cybersecurity frameworks. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other applications and systems within the organization's infrastructure.