# Unsanitized User Input in File Path

## Overview

* **Rule ID**: `java_lang_path_using_user_input`
* **Applicable Languages**: Java
* **Weakness ID**: CWE-73

## Description

Unsanitized user input in file path resolution can lead to security vulnerabilities. This issue arises when an application directly uses input from the user to determine file paths or names without proper validation or sanitization. Attackers can exploit this to access unauthorized files or directories, leading to data breaches or other security compromises.

## Remediation Guidelines

* **Avoid** incorporating user input directly into file paths without proper sanitization, as this practice can enable attackers to manipulate file paths and potentially access unauthorized files.
* **Instead, employ a safelist to specify permissible paths or directories**. Limit user input to influence file paths only within these predefined, secure boundaries.
* **Ensure to sanitize user input used in file path resolution**. For instance, utilize methods like `FilenameUtils.getName()` to safely extract the intended file name from user input, thereby mitigating any attempts at path manipulation.

  ```java
  public class Cls extends HttpServlet
    {
        public void handleRequest(HttpServletRequest request, HttpServletResponse response)
          {
            String image = request.getParameter("user_profile_picture");
            File file = new File("user/profile/" + FilenameUtils.getName(image));
          }
    }

  ```

## References

* [**CWE-73: External Control of File Name or Path**](https://cwe.mitre.org/data/definitions/73.html)
* [**OWASP Top 10: A04:2021 - Insecure Design**](https://owasp.org/Top10/A04_2021-Insecure_Design/)

## Configuration

To omit this rule during a scan, and to provide you with continuous 24/7 code-level scanning, you can employ our [**SAST TOOL**](https://scopy.sec1.io/login)


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