CVE-2017-16132 in simple-npm-registry
Summary
by MITRE
simple-npm-registry is a local npm package cache. simple-npm-registry 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 • 02/16/2020
The CVE-2017-16132 vulnerability affects simple-npm-registry, a local npm package cache implementation that serves as a lightweight alternative to full npm registries. This tool is designed to cache npm packages locally, reducing bandwidth usage and improving performance for development environments. The vulnerability stems from inadequate input validation within the URL parsing mechanism, specifically failing to properly sanitize or normalize file paths that are processed through the registry interface. Attackers can exploit this weakness by crafting malicious URLs containing directory traversal sequences such as "../" which allows them to navigate outside the intended cache directory structure and access arbitrary files on the underlying filesystem.
The technical flaw manifests as a classic path traversal vulnerability where the application does not properly validate or sanitize user-supplied URLs before using them to resolve file paths. When a request is made with a URL containing "../" sequences, the application processes these without adequate sanitization, allowing attackers to traverse up the directory hierarchy and potentially access sensitive files, configuration data, or system resources that should remain isolated from the registry service. This vulnerability 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 impact is particularly severe in environments where the registry service runs with elevated privileges or has access to sensitive system information.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could enable attackers to access critical system files, configuration databases, or even execute arbitrary code if the registry service has permissions to read or modify system resources. In development environments where simple-npm-registry might be used with default configurations, this vulnerability could provide attackers with access to source code repositories, build artifacts, or other sensitive data stored within the cache directory structure. The vulnerability also aligns with ATT&CK technique T1083, which covers discovering file and directory permissions, as attackers could use this traversal capability to identify and access files they should not normally have access to, potentially leading to privilege escalation or further system compromise.
Mitigation strategies should focus on implementing proper input validation and sanitization for all URL parameters before they are processed by the registry service. The most effective approach involves normalizing all file paths through canonicalization functions that resolve directory traversal sequences and ensure all paths remain within the designated cache directory boundaries. Organizations should also consider implementing least privilege principles for registry services, ensuring they operate with minimal required permissions and are isolated from sensitive system resources. Additionally, regular security auditing of third-party npm registry implementations and maintaining updated versions of all dependencies can prevent exploitation of known vulnerabilities. The fix should include comprehensive testing of path resolution logic to ensure that all traversal sequences are properly handled and that the service maintains strict boundaries around its intended file system access scope.