How to Ensure No Unexpected Query String Parameters are Passed in Spring MVC?

How can I ensure that no unexpected query string parameters are being passed in a Spring MVC application?

@Controller
public class MyController {

    @RequestMapping("/example")
    public String handleRequest(@RequestParam Map<String, String> allParams) {
        // Your logic here
    }
}

In Spring MVC, to maintain application integrity and security, it's essential to validate query string parameters to ensure that only the expected parameters are processed. This helps prevent potential exploits, such as injection attacks or unexpected behavior.

@Controller
public class ExampleController {

    @RequestMapping("/data")
    public String fetchData(@RequestParam Map<String, String> queryParams) {
        // Define accepted parameters
        List<String> allowedParams = Arrays.asList("param1", "param2");
        // Filter out unexpected parameters
        queryParams.keySet().removeIf(key -> !allowedParams.contains(key));

        // Proceed with the validated parameters
        return "data";
    }
}

Causes

• Misconfigured servers allowing unexpected parameters.
• Lack of validation logic in the controller.
• Potential misuse by clients or APIs.

Solutions

• Use `@RequestParam` to explicitly define expected parameters.
• Implement a validation mechanism that checks for unwanted parameters in the request map.
• Utilize Spring's built-in validators or create custom validators.

Mistake: Not checking the existence of parameters before processing them.

Solution: Always verify if the required parameters are present before executing your logic.

Mistake: Relying solely on client-side validation.

Solution: Always validate on the server-side as client-side validation can be bypassed.