CVE-2022-31584 in s3label
Summary
by MITRE • 07/11/2022
The stonethree/s3label repository through 2019-08-14 on GitHub allows absolute path traversal because the Flask send_file function is used unsafely.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 07/21/2022
The vulnerability identified as CVE-2022-31584 resides within the stonethree/s3label repository, a tool designed for managing S3 bucket labels and configurations. This repository, as of its last update on August 14, 2019, contains a critical security flaw that enables attackers to perform absolute path traversal attacks through improper usage of the Flask web framework's send_file function. The vulnerability represents a significant risk to systems that rely on this tool for S3 bucket management operations.
The technical flaw stems from the insecure implementation of the Flask send_file function, which is designed to serve files from the filesystem to HTTP clients. When used unsafely, this function can be manipulated to access arbitrary files on the server's filesystem by crafting malicious requests that include absolute paths or directory traversal sequences. The vulnerability specifically allows attackers to bypass intended access controls and retrieve sensitive files that should remain protected, including configuration files, credentials, or other system resources. This occurs because the application fails to properly validate or sanitize file paths before passing them to the send_file function, creating an unrestricted file access condition.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to escalate their privileges and gain unauthorized access to sensitive system resources. An attacker who successfully exploits this vulnerability can potentially retrieve system configuration files, database connection details, API keys, or other confidential data stored within the application's filesystem. The implications are particularly severe for organizations using this tool in production environments where it may be handling sensitive S3 bucket configurations or access credentials. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The attack vector aligns with techniques documented in the MITRE ATT&CK framework under the T1059.001 technique for command and scripting interpreter, where attackers can leverage such vulnerabilities to execute unauthorized file system operations.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and sanitization measures. Organizations should ensure that all file paths passed to the Flask send_file function are properly validated against a whitelist of allowed directories and file extensions. The recommended approach involves implementing absolute path resolution with strict directory restrictions, ensuring that file access operations are confined to predetermined safe locations. Additionally, developers should consider implementing proper authentication and authorization checks before file access operations, and the application should be updated to use secure file serving methods that do not expose the underlying filesystem structure. Regular security audits and code reviews should be conducted to identify similar patterns in other parts of the application or related systems. The fix should also include implementing proper error handling to prevent information leakage through error messages that might reveal system file paths or internal application structure.