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# Leakage of sensitive data in JWT

## Overview

* **Rule ID**: `javascript_lang_jwt`
* **Applicable Languages**: Javascript
* **Weakness ID**: CWE-312

## Description

Storing sensitive data in JWTs exposes it to potential security risks. While JWTs are meant for securely transmitting data between parties, they are not inherently secure for storing sensitive information.

## Remediation Guidelines

* **Avoid** including sensitive data, such as email addresses, in JWTs. This can result in unauthorized access to personal information.

  ```java
  const jwt = require('jsonwebtoken');
  const token = jwt.sign({ user: { email: 'john@gmail.com' }}); // unsafe


  ```
* **Use non-sensitive**, unique identifiers like a user's UUID in JWTs to reference user information securely.

  ```java
  const jwt = require('jsonwebtoken');
  const token = jwt.sign({ user: user.uuid });
  ```

## References

* [**OWASP sensitive data exposure**](https://owasp.org/www-project-top-ten/2017/A3_2017-Sensitive_Data_Exposure)
* [**CWE-312: Cleartext Storage of Sensitive Information**](https://cwe.mitre.org/data/definitions/312.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)