CVE-2022-31532 in travel_blahg
Summary
by MITRE • 07/11/2022
The dankolbman/travel_blahg repository through 2016-01-16 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-2022-31532 resides within the dankolbman/travel_blahg repository, which was active until January 16, 2016, and hosted on GitHub. This repository implemented a web application using the Flask framework, which introduced a critical security flaw through improper handling of file serving operations. The issue manifests when the Flask send_file function is invoked without adequate input validation or sanitization, creating an avenue for attackers to manipulate file paths and access arbitrary files on the server filesystem.
The technical root cause of this vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. When Flask's send_file function receives an unsanitized file path parameter, it fails to properly validate or canonicalize the input before attempting to serve the requested file. This allows malicious users to craft requests containing sequences like ../ that can navigate outside the intended directory structure and access files that should remain protected. The vulnerability operates at the application layer and represents a classic example of unsafe file handling practices that have been consistently documented in security frameworks and best practices.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to potentially access sensitive files including configuration files, database credentials, application source code, and other confidential data stored on the server. In the context of web applications, this type of vulnerability can lead to complete system compromise, especially when combined with other attack vectors or when the application runs with elevated privileges. The threat landscape for such vulnerabilities aligns with ATT&CK technique T1083, which covers the discovery of system information through directory listing and file access enumeration. Organizations using vulnerable applications may experience data breaches, regulatory compliance violations, and reputational damage when attackers successfully exploit this weakness.
Mitigation strategies for CVE-2022-31532 require immediate attention to the application codebase and implementation of proper input validation and path sanitization measures. The recommended approach involves ensuring that all file paths passed to Flask's send_file function are properly validated against a whitelist of allowed directories or that absolute paths are resolved to a canonical form before file operations occur. Security professionals should implement proper access controls, use secure coding practices, and consider employing web application firewalls to detect and block malicious path traversal attempts. Additionally, regular security audits and code reviews should be conducted to identify and remediate similar vulnerabilities in other components of the application stack. Organizations should also consider implementing principle of least privilege access controls and monitoring for suspicious file access patterns to detect potential exploitation attempts.