APPL-09

Does the system provide data input validation and error messages?

Explanation

This question is asking whether your application or service has mechanisms to validate user inputs and provide appropriate error messages when invalid data is entered. Data input validation is a security control that verifies whether the data entered into an application meets specific criteria before it's processed. This helps prevent security vulnerabilities like SQL injection, cross-site scripting (XSS), buffer overflows, and other injection attacks that could occur when malicious or malformed data is processed without proper checking. Error messages are the feedback provided to users when validation fails. Good error messages should be informative enough to help legitimate users correct their mistakes but not so detailed that they reveal sensitive information about the system's internal workings to potential attackers. This question is asked in security assessments because: 1. Input validation is a fundamental security control that prevents many common vulnerabilities 2. Proper error handling prevents information leakage that could help attackers 3. It demonstrates that the application follows secure coding practices 4. It shows that the application has defense-in-depth measures against data manipulation attacks When answering this question, you should: - Describe the types of input validation implemented (client-side, server-side, or both) - Explain how validation is performed (e.g., data type checking, range checking, format validation) - Describe how error messages are generated and what information they contain - Mention any frameworks or libraries used for validation - Note any special handling for security-sensitive fields

Example Responses

Example Response 1

Yes, our system implements comprehensive data input validation at multiple levels We employ both client-side validation using JavaScript for immediate user feedback and server-side validation to ensure security regardless of client-side bypasses All user inputs are validated for proper data types, length constraints, format requirements (using regular expressions where appropriate), and business rule compliance For example, email fields are validated using RFC 5322 compliant patterns, numeric fields are checked for range constraints, and all text inputs are sanitized to prevent injection attacks Our error messages are designed to be helpful to legitimate users while avoiding information disclosure that could aid attackers For instance, when a password doesn't meet complexity requirements, the error message explains the requirements without revealing whether the username exists in our system We use a combination of our web framework's built-in validation features and custom validation logic, with all validation failures being logged for security monitoring purposes.

Example Response 2

Yes, our application implements robust input validation throughout the system We use a layered approach with both frontend and backend validation On the frontend, we use Angular's FormControl validators to provide immediate feedback to users about invalid inputs On the backend, all inputs are re-validated using our custom validation framework that performs type checking, boundary validation, and format verification For API endpoints, we use OpenAPI/Swagger specifications to define and enforce valid request schemas Our system provides contextual error messages that guide users to correct their inputs without revealing system implementation details For example, when validating a credit card number, the system checks the format, performs Luhn algorithm validation, and provides specific feedback like "Please enter a valid credit card number" rather than exposing the validation logic All validation failures are tracked in our application monitoring system to identify potential attack patterns or usability issues.

Example Response 3

No, our system currently has limited input validation capabilities We rely primarily on database constraints and application logic to handle invalid inputs rather than having a dedicated validation framework While some critical fields like login credentials have basic validation, many form fields lack comprehensive checks Error messages are generally generic (e.g., "An error occurred") and don't provide specific guidance on how to correct invalid inputs We recognize this as a security gap and have included enhanced input validation in our next development sprint Our planned improvements include implementing server-side validation for all user inputs, adding client-side validation for better user experience, and creating more descriptive error messages that help users correct their inputs without exposing system details We expect these improvements to be deployed within the next 60 days.

Context

Tab: Infrastructure
Category: Application/Service Security