CVE-2019-5437 in Harp Module
Summary
by MITRE
Information exposure through the directory listing in npm's harp module allows to access files that are supposed to be ignored according to the harp server rules.Vulnerable versions are <= 0.29.0 and no fix was applied to our knowledge.
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Analysis
by VulDB Data Team • 09/15/2023
The vulnerability identified as CVE-2019-5437 represents a critical information exposure flaw within npm's harp module, specifically affecting versions up to and including 0.29.0. This vulnerability stems from improper directory listing implementation that fails to respect the intended server rules for file access control. The harp module, designed as a static site generator and web server, is responsible for serving content while maintaining proper access restrictions based on configuration rules. However, the flaw allows malicious actors to enumerate and access files that should normally be protected or ignored according to the server's intended access policies. This represents a significant deviation from expected security controls where the module fails to properly enforce its own access control mechanisms.
The technical root cause of this vulnerability lies in the directory listing functionality of the harp server implementation, which does not adequately validate or filter file access requests. When the server processes requests for directory contents, it fails to properly apply the ignore patterns or access control rules that are typically configured to prevent unauthorized access to sensitive files. This misconfiguration creates a scenario where any user with access to the server can traverse directories and retrieve files that should be protected, potentially exposing sensitive data, configuration files, or system information that would normally be restricted. The vulnerability is classified as an information exposure issue where the server provides more information than intended, violating fundamental security principles of least privilege and access control. According to CWE standards, this corresponds to CWE-200, which addresses information exposure through improper access control mechanisms.
The operational impact of CVE-2019-5437 is substantial as it can lead to unauthorized data access and potential information disclosure attacks. Attackers can exploit this vulnerability to access files that may contain sensitive information such as database credentials, API keys, configuration files, or other confidential data that should remain protected. The vulnerability affects any system using the affected version of the harp module, making it particularly concerning for organizations that rely on npm-based static site generation and deployment workflows. This flaw undermines the security posture of web applications that depend on harp for serving content, as it allows bypassing the intended access control mechanisms. The lack of a fix for this vulnerability means that affected systems remain permanently exposed to potential exploitation, creating a persistent risk that could be leveraged by threat actors to gain unauthorized access to sensitive resources.
Organizations affected by this vulnerability should immediately implement mitigation strategies to reduce the risk of exploitation. The most effective immediate solution involves upgrading to a version of the harp module that addresses this security flaw, though as noted in the vulnerability description, no fix was applied to the affected versions. System administrators should consider implementing additional access controls at the network level, such as firewall rules or reverse proxy configurations that restrict access to the harp server endpoints. Regular security audits should be conducted to identify any sensitive files that might be exposed through this vulnerability, and proper file permissions should be enforced to limit access at the filesystem level. The vulnerability also highlights the importance of proper security testing for web applications, particularly those using static site generators, as it demonstrates how seemingly benign functionality can create security risks when access controls are improperly implemented. Organizations should also consider implementing monitoring solutions to detect unauthorized access attempts to web server endpoints that could indicate exploitation of this vulnerability.