Course

The Code Review Patch challenges aim to enhance your ability to spot security flaws in code by providing both the vulnerable code and the patch. In this particular lab, you are presented with the `TokenFilter.java` file from an Apache IoTDB project. The task is to identify the security issue in the code without initially looking at the patch. If you struggle to find the issue or need confirmation, you can refer to the patch file, which shows the necessary corrections.

The vulnerable code uses the `Auth0` JWT library and constructs a JWT verifier with a key derived from the local host address. This approach can lead to issues if the host address is not correctly resolved. The patch replaces this mechanism by utilizing the `io.jsonwebtoken` library to parse and validate the JWT tokens more robustly. The patch also includes additional checks to ensure the presence and validity of the token and its claims, thereby strengthening the security of the application.