Guide: Input Validation on CompTIA Security+ Exam

Input validation is a critical functionality in securing applications. This process checks whether the data supplied by an application user is valid and safe before it is processed.

Importance:
Input validation helps to prevent attacks such as SQL injection, cross-site scripting (XSS), and remote code execution. These attacks can occur when an application processes invalid data. With input validation, you ensure that only the correct type, length, and format of data is considered valid.

How it works:
Input validation involves establishing a set of rules for what is considered valid data. This could mean checking if a user's email address contains an '@' symbol and a dot, or checking if a phone number only contains digits.

Exam Tips: Answering Questions on Input Validation
1. Understand the basic principle: the main idea to grasp about input validation is that it's ​a method of ensuring only properly formatted data enters a software system.
2. Remember its purpose: know that its primary purpose is to protect against malicious or malformed input, reducing the likelihood of successful attacks.
3. Learn the strategies: familiarize yourself with different strategies of input validation such as whitelisting, blacklisting, and canonicalization.
4. Case studies: study common scenarios where input validation is used to prevent specific types of software attacks.
5. Practical Implementation: think in terms of how to implement input validation in real-world situations.
6. Exam questions may present a scenario where input validation can be used to mitigate a security risk - consider this when examining the question's options.