EC-Council Certified Ethical Hacker (CEH) v12Web Application HackingMedium

A web application developer is designing a new API endpoint that accepts JSON payloads containing user data. To prevent malicious data from being processed, the developer wants to ensure that all incoming JSON data strictly conforms to a predefined schema, rejecting any requests with extra fields or incorrect data types. Which web application security concept is the developer implementing?

  1. AContent Security Policy (CSP)
  2. BOutput Encoding
  3. CSchema Validation
  4. DRate Limiting
Show answer & explanation

Correct answer: C. Schema Validation

Schema Validation is the process of ensuring that incoming data (like JSON payloads) conforms to a predefined structure, data types, and constraints, which helps prevent various injection and malformed data attacks.

Why the other options are wrong

  • A. CSP is a security mechanism that helps mitigate XSS and data injection attacks by specifying trusted content sources.
  • B. Output Encoding is used to prevent XSS by encoding data before displaying it to the user.
  • D. Rate Limiting controls the number of requests a user can make in a given period to prevent brute-force attacks or DoS.

Schema Validation

Schema Validation is the process of verifying that a given data structure (like XML or JSON) conforms to a predefined schema, ensuring correctness and integrity.

  • Enforces data types, field names, required fields, and structural constraints.
  • Prevents malformed data from being processed, reducing attack surface.
  • Commonly used for API inputs and configuration files.

Memory trick: APIs Guard Data with Strict Schemas.

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