CVE-2022-31531 in cilantro
Summary
by MITRE • 07/11/2022
The dainst/cilantro repository through 0.0.4 on GitHub allows absolute path traversal because the Flask send_file function is used unsafely.
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Analysis
by VulDB Data Team • 07/20/2022
The vulnerability identified as CVE-2022-31531 resides within the dainst/cilantro repository version 0.0.4 and earlier, presenting a critical security risk through improper handling of file operations. This repository implements a web application using the Flask framework, which is commonly employed for building web services and applications. The core issue manifests when the Flask send_file function is invoked without proper validation of file paths, creating an opportunity for attackers to access arbitrary files on the server filesystem. The vulnerability stems from the application's failure to sanitize user-provided input that influences file path resolution, allowing malicious actors to manipulate the application's file access behavior.
The technical flaw constitutes a path traversal attack vector where an attacker can exploit the unsafe usage of Flask's send_file function to navigate the filesystem beyond intended boundaries. When the application receives a request containing a file path parameter, it directly passes this input to send_file without implementing proper path validation or sanitization measures. This oversight enables attackers to construct malicious paths using sequences such as ../ or absolute paths that bypass normal file access controls. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The specific implementation flaw demonstrates how unsafe file handling can lead to unauthorized data access and potential system compromise.
The operational impact of this vulnerability extends beyond simple file access, potentially allowing attackers to extract sensitive information, credentials, configuration files, or even execute arbitrary code if the application has sufficient privileges. An attacker could leverage this vulnerability to access database connection strings, API keys, or other confidential data stored on the server. The risk is particularly severe in environments where the web application runs with elevated privileges or has access to sensitive data repositories. This vulnerability can be exploited through various attack vectors including direct URL manipulation, parameter injection, or through web application interfaces that accept file path parameters. The potential for data exfiltration and system compromise makes this vulnerability particularly dangerous in production environments.
Mitigation strategies should focus on implementing proper input validation and sanitization of all file path parameters before they are processed by Flask's send_file function. The recommended approach involves creating a whitelist of allowed file paths or implementing strict path validation that prevents traversal beyond designated directories. Organizations should enforce the principle of least privilege by ensuring that web applications run with minimal necessary permissions and that file access is restricted to specific directories. Additionally, implementing proper logging and monitoring mechanisms can help detect and respond to exploitation attempts. The solution aligns with ATT&CK technique T1083, which covers the discovery of system information through directory listing and file access. Security teams should also consider implementing web application firewalls and input validation rules to prevent malicious path traversal attempts. Regular security assessments and code reviews focusing on file handling operations can help identify and remediate similar vulnerabilities in other applications. The vulnerability serves as a reminder of the critical importance of secure file handling practices and proper input validation in web application development, particularly when using frameworks like Flask that provide powerful but potentially dangerous file operations.