CVE-2022-31550 in pyathenastack
Summary
by MITRE • 07/11/2022
The olmax99/pyathenastack repository through 2019-11-08 on GitHub allows absolute path traversal because the Flask send_file function is used unsafely.
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Analysis
by VulDB Data Team • 07/21/2022
The vulnerability identified as CVE-2022-31550 resides within the olmax99/pyathenastack repository, specifically manifesting in versions through 2019-11-08. This repository implements a web application using the Flask framework, which introduces a critical security flaw through improper handling of file serving operations. The vulnerability stems from the unsafe usage of Flask's send_file function, which creates an avenue for attackers to access arbitrary files on the server filesystem. The repository's implementation fails to properly validate or sanitize user-provided file paths, allowing malicious actors to manipulate the application's file access behavior.
The technical flaw represents a classic path traversal vulnerability that operates at the application layer, specifically targeting the file serving mechanism within Flask. When the send_file function receives user input without proper sanitization or validation, it becomes susceptible to absolute path traversal attacks. Attackers can manipulate the input parameters to navigate beyond the intended directory boundaries and access files that should remain protected. This vulnerability falls under the CWE-22 category, which specifically addresses path traversal flaws, and can be categorized as a CWE-427 - Uncontrolled Search Path Element, where the application's search path becomes manipulated by external input. The flaw directly enables attackers to bypass normal access controls and potentially obtain sensitive information, including configuration files, source code, or other system files that may contain credentials or other exploitable data.
The operational impact of this vulnerability is significant as it allows remote attackers to perform unauthorized file access operations on the affected system. An attacker could potentially access critical system files, application configuration data, database credentials, or other sensitive information stored on the server. The vulnerability enables a range of malicious activities including information disclosure, privilege escalation, and potentially system compromise. Since the vulnerability exists in a web application context, it can be exploited remotely without requiring local system access, making it particularly dangerous. The attack surface is broad as any functionality that relies on user-provided file paths or names could be exploited, potentially affecting the entire application's data integrity and confidentiality. This vulnerability aligns with ATT&CK technique T1083 - File and Directory Discovery, where adversaries attempt to enumerate files and directories to understand the system's structure and identify valuable targets.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization for all file-related operations within the Flask application. The recommended approach involves using absolute path validation techniques that ensure file access requests are confined to predefined directories. Developers should implement strict path validation that rejects any input containing directory traversal sequences such as ../ or ..\, and should always use secure file access methods that prevent path manipulation. The Flask application should be configured to use a whitelist approach for file access, where only specific, authorized directories and files are accessible through the application's interface. Additionally, the application should implement proper access controls and authentication mechanisms to limit who can perform file access operations. The fix should include updating the repository to properly sanitize all user inputs before passing them to the send_file function, and implementing proper error handling to prevent information leakage through error messages that might reveal system paths or file structures. Organizations should also consider implementing web application firewalls and security monitoring to detect and prevent exploitation attempts of this vulnerability.