Input validation and sanitization in Cybersecurity - Mini Project: Build & Apply

Input Validation and Sanitization

📖 Scenario: You are working on a simple web form that collects user information. To keep the system safe, you need to make sure the input data is checked and cleaned before using it.

🎯 Goal: Build a step-by-step process to validate and sanitize user input data to prevent common security issues.

📋 What You'll Learn

Create a dictionary with user input data

Add a configuration variable for allowed characters

Write logic to validate and sanitize the input

Complete the process by marking inputs as safe or unsafe

💡 Why This Matters

🌍 Real World

Input validation and sanitization are essential to protect websites and applications from harmful data that can cause errors or security breaches.

💼 Career

Understanding how to validate and sanitize input is a key skill for cybersecurity professionals, web developers, and software engineers to ensure safe and reliable software.

1

Create user input data dictionary

Create a dictionary called user_input with these exact entries: 'username': 'john_doe!', 'email': '[e-mail]', 'age': '25'

Cybersecurity

# Create the user_input dictionary with the specified entries
# Your code here

Need a hint?

Use curly braces to create a dictionary with keys and values exactly as shown.

2

Add allowed characters configuration

Create a variable called allowed_chars and set it to the string 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_@.' to specify which characters are allowed in inputs.

Cybersecurity

user_input = {'username': 'john_doe!', 'email': '[e-mail]', 'age': '25'}
# Define allowed_chars string with letters, digits, underscore, @, and dot
# Your code here

Need a hint?

Use a string variable to list all allowed characters exactly as shown.

3

Validate and sanitize user input

Create a new dictionary called sanitized_input. Use a for loop with variables key and value to iterate over user_input.items(). For each value, create a new string containing only characters found in allowed_chars. Assign this cleaned string to sanitized_input[key].

Cybersecurity

user_input = {'username': 'john_doe!', 'email': '[e-mail]', 'age': '25'}
allowed_chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_@.'
# Create sanitized_input dictionary and clean each value
# Your code here

Need a hint?

Use a dictionary comprehension or a loop to filter each input value by allowed characters.

4

Mark inputs as safe or unsafe

Create a dictionary called input_status. Use a for loop with variables key and value to iterate over user_input.items(). For each key, compare value with sanitized_input[key]. If they are equal, set input_status[key] to 'safe', otherwise set it to 'unsafe'.

Cybersecurity

user_input = {'username': 'john_doe!', 'email': '[e-mail]', 'age': '25'}
allowed_chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_@.'
sanitized_input = {}
for key, value in user_input.items():
    cleaned = ''.join(char for char in value if char in allowed_chars)
    sanitized_input[key] = cleaned
# Create input_status dictionary and mark inputs safe or unsafe
# Your code here

Need a hint?

Compare original and sanitized values to decide if input is safe or unsafe.