CVE-2019-5447 in http-file-server
Summary
by MITRE
A path traversal vulnerability in <= v0.2.6 of http-file-server npm module allows attackers to list files in arbitrary folders.
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Analysis
by VulDB Data Team • 10/26/2023
The CVE-2019-5447 vulnerability represents a critical path traversal flaw within the http-file-server npm module version 0.2.6 and earlier. This vulnerability stems from insufficient input validation and improper handling of file paths when processing HTTP requests. The flaw allows malicious actors to manipulate the module's file serving functionality by crafting specific URL parameters that bypass normal directory restrictions. When the module processes these crafted requests, it fails to properly sanitize or validate the requested file paths, enabling attackers to traverse the filesystem and access files outside of the intended document root directory.
The technical implementation of this vulnerability occurs at the application layer where the http-file-server module fails to properly canonicalize or resolve file paths before serving content. Attackers can exploit this by appending directory traversal sequences such as ../ or ..\ to file requests, which allows them to navigate upward through the directory structure and access files that should remain protected. This weakness 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 vulnerability exists because the module does not implement proper path normalization or validation mechanisms that would prevent such malicious path manipulation attempts.
The operational impact of this vulnerability extends beyond simple file enumeration, as it provides attackers with unauthorized access to potentially sensitive files within the server's filesystem. An attacker who successfully exploits this vulnerability can list directories, read arbitrary files, and potentially gain access to configuration files, database credentials, application source code, or other sensitive data that should remain protected. This access can lead to further compromise of the system, including potential privilege escalation or lateral movement within the network. The vulnerability affects any system running the vulnerable version of http-file-server, making it particularly dangerous in environments where this module is used for file serving or web content delivery.
Mitigation strategies for CVE-2019-5447 should focus on immediate version updates to the http-file-server module, as the vulnerability has been addressed in subsequent releases. Organizations should implement comprehensive patch management processes to ensure all instances of the vulnerable module are updated promptly. Additionally, network-level protections such as web application firewalls and intrusion detection systems can help detect and block suspicious path traversal attempts. Security teams should also consider implementing proper input validation and sanitization measures, including the use of allowlists for valid file paths and proper path resolution techniques. The ATT&CK framework categorizes this vulnerability under T1083 - File and Directory Discovery, highlighting the reconnaissance phase that attackers use to map the target environment. Organizations should conduct thorough security assessments to identify all instances of the vulnerable module and implement proper access controls to limit the potential impact of such vulnerabilities.