CVE-2018-3713 in angular-http-server
Summary
by MITRE
angular-http-server node module suffers from a Path Traversal vulnerability due to lack of validation of possibleFilename, which allows a malicious user to read content of any file with known path.
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Analysis
by VulDB Data Team • 02/16/2020
The angular-http-server node module contains a critical path traversal vulnerability identified as CVE-2018-3713 that stems from insufficient input validation within the possibleFilename parameter processing. This vulnerability resides in the server-side file handling mechanism where the module fails to properly sanitize user-supplied file paths before accessing the file system. The flaw allows attackers to manipulate the file path parameter to traverse directories and access files that should normally be restricted or protected. The vulnerability is particularly dangerous because it enables arbitrary file reading capabilities that can expose sensitive system information, configuration files, source code, and other confidential data to unauthorized parties. Security researchers have classified this issue as a path traversal vulnerability, which maps directly to CWE-22 - Improper Limitation of a Pathname to a Restricted Directory. The vulnerability exists in the module's handling of file requests where it directly uses user input without proper validation or sanitization, creating an attack surface that can be exploited by malicious actors.
The technical implementation of this vulnerability occurs when the angular-http-server processes HTTP requests for static files, specifically when handling file path parameters. The module accepts user-provided file names or paths through the possibleFilename parameter without implementing proper input validation or sanitization measures. Attackers can exploit this by crafting malicious requests that include directory traversal sequences such as '../' or '..\'. When the server processes these requests, it fails to validate or sanitize the input, allowing the traversal to occur and potentially access files outside of the intended document root directory. This type of vulnerability is particularly concerning in web server contexts where the application might have elevated privileges to access system files. The attack vector follows established patterns described in the ATT&CK framework under technique T1083 - File and Directory Discovery, where adversaries enumerate system resources to identify sensitive files. The vulnerability essentially allows attackers to bypass normal access controls and retrieve files that should be protected, making it a serious security concern for any system utilizing this module.
The operational impact of CVE-2018-3713 extends beyond simple information disclosure to potentially enable more sophisticated attacks. An attacker who successfully exploits this vulnerability can access not only configuration files and application source code but also system-level files that might contain credentials, database connection strings, or other sensitive information. The vulnerability can be leveraged to extract sensitive data from the server, potentially leading to further compromise of the system through credential theft or privilege escalation. The impact is particularly severe in environments where the server runs with elevated privileges or where the angular-http-server module is used in production applications. Organizations using this module may face regulatory compliance issues if sensitive data is exposed, and the vulnerability can be exploited to gain insights into the application architecture and underlying system configuration. The vulnerability also represents a potential entry point for attackers to conduct reconnaissance activities and gather information for more advanced attacks. According to industry best practices and security standards, this vulnerability demonstrates the critical importance of input validation and proper access controls, which are fundamental requirements in secure coding practices and are referenced in various security frameworks including ISO 27001 and NIST cybersecurity guidelines.
Mitigation strategies for CVE-2018-3713 should focus on immediate remediation through module updates or patches provided by the maintainers. Organizations should implement proper input validation mechanisms that sanitize all user-supplied file paths before processing them, ensuring that directory traversal sequences are properly filtered or rejected. The implementation should include path normalization techniques and strict validation against allowed file paths to prevent unauthorized access. Security teams should also consider implementing web application firewalls or security controls that can detect and block suspicious path traversal attempts. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other modules or applications. Additionally, organizations should limit the privileges under which the angular-http-server module operates and implement principle of least privilege access controls. The recommended approach aligns with defensive security measures outlined in the OWASP Top Ten and follows the principle of defense in depth, ensuring that multiple layers of security controls are implemented to protect against path traversal attacks. System administrators should also monitor for unusual file access patterns and implement logging mechanisms to detect potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of validating all inputs and implementing proper access controls, which are fundamental security principles that should be incorporated into all software development lifecycle processes.