CVE-2022-31555 in nursequest
Summary
by MITRE • 07/11/2022
The romain20100/nursequest repository through 2018-02-22 on GitHub allows absolute path traversal because the Flask send_file function is used unsafely.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/21/2022
The vulnerability identified as CVE-2022-31555 resides within the romain20100/nursequest repository, a web application built using the Flask framework. This issue represents a critical security flaw that allows attackers to access arbitrary files on the server by exploiting unsafe usage of the Flask send_file function. The vulnerability specifically manifests in versions of the repository up to and including the commit dated 2018-02-22, making it a long-standing weakness that could have been exploited for extended periods. The repository's web application interface fails to properly validate file paths before serving files, creating an opportunity for malicious users to traverse the file system and potentially access sensitive data or system files. This type of vulnerability falls under the category of path traversal attacks, which are commonly classified as CWE-22 according to the Common Weakness Enumeration catalog.
The technical implementation of this vulnerability stems from the improper handling of file paths within the Flask application's file serving mechanism. When the send_file function is invoked without proper sanitization or validation of the input parameters, attackers can manipulate the file path parameter to include directory traversal sequences such as "../" or absolute paths that bypass intended access controls. The Flask framework's send_file function is designed to securely serve files from within a specified directory, but when used with user-controllable input, it becomes vulnerable to manipulation. This flaw represents a direct violation of secure coding practices and demonstrates the importance of input validation and proper file access controls in web applications. The vulnerability is particularly concerning because it can potentially allow attackers to access not only application files but also system configuration files, database files, or other sensitive resources that should remain protected.
The operational impact of this vulnerability extends beyond simple information disclosure and could enable more severe attacks within the compromised system. An attacker who successfully exploits this vulnerability could gain access to sensitive application data, configuration files, or even system-level information that could be used for further exploitation. The ability to perform absolute path traversal means that attackers could potentially access files outside the intended web root directory, potentially leading to privilege escalation or data exfiltration. This vulnerability could be particularly damaging in environments where the web application serves as a gateway to internal systems or where sensitive data is stored on the same server. The attack surface is significant as it could affect any user of the application who has access to the file serving functionality, and the exploitation requires minimal technical skill to execute successfully.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization of all file path parameters before they are processed by the Flask send_file function. The recommended approach includes implementing strict path validation that ensures all file requests are contained within a designated safe directory and rejecting any requests that attempt to traverse outside of this allowed scope. Organizations should implement proper access controls and file permission settings to limit what files can be accessed through the application. Additionally, the application should be updated to use a more secure method of file serving that does not rely on user input for determining file paths. Security measures should also include regular code reviews and vulnerability assessments to identify similar issues in other parts of the application. The remediation process should involve implementing proper error handling and logging to detect and respond to suspicious file access attempts, aligning with defensive practices recommended by the MITRE ATT&CK framework for web application security. Organizations should also consider implementing web application firewalls and additional monitoring to detect potential exploitation attempts of this vulnerability.