CVE-2022-31547 in sphere
Summary
by MITRE • 07/11/2022
The noamezekiel/sphere repository through 2020-05-31 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-2022-31547 resides within the noamezekiel/sphere repository, a project hosted on GitHub and maintained through at least May 31, 2020. This issue represents a critical security flaw that stems from improper implementation of file handling within a Flask web application framework. The repository's use of the Flask send_file function in an unsafe manner creates a condition where attackers can manipulate file paths to access arbitrary files on the server filesystem. This vulnerability directly enables unauthorized access to sensitive data and system resources that should remain protected.
The technical flaw manifests through the insecure usage of Flask's send_file function which is designed to safely serve files from the server to clients. When developers utilize this function without proper input validation or path sanitization, they create an opportunity for attackers to manipulate the file path parameter. In this specific case, the application fails to properly validate or sanitize user-supplied input that gets passed to send_file, allowing absolute path traversal attacks. Attackers can craft malicious requests that bypass normal file access controls and retrieve files from locations outside the intended web root directory. This vulnerability is categorized under CWE-22, which specifically addresses Improper Limitation of a Pathname to a Restricted Directory, commonly known as path traversal attacks.
The operational impact of CVE-2022-31547 extends beyond simple data theft, as it can enable more sophisticated attack vectors within the compromised system. An attacker who successfully exploits this vulnerability can access configuration files, source code, database credentials, and other sensitive information stored on the server. The implications are particularly severe for web applications that handle sensitive data or operate in regulated environments where data protection is paramount. This vulnerability can be exploited through various methods including direct URL manipulation, parameter injection, or through web application interfaces that accept file path parameters. The attack surface is broad as any function or endpoint that uses the vulnerable send_file implementation could be targeted.
Mitigation strategies for CVE-2022-31547 must focus on implementing proper input validation and sanitization mechanisms before any file operations occur. The most effective approach involves using Flask's built-in security features such as proper path validation, implementing secure file serving practices, and ensuring that all user-supplied paths are normalized and validated against a whitelist of acceptable directories. Organizations should also consider implementing proper access controls and file permission settings to limit what files can be accessed even if path traversal attempts occur. The remediation process requires careful code review and modification of any instances where send_file is used without proper validation. Additionally, implementing proper logging and monitoring for file access patterns can help detect and respond to exploitation attempts. This vulnerability aligns with ATT&CK technique T1083, which covers File and Directory Discovery, and represents a classic example of how insecure file handling can lead to privilege escalation and data compromise.