SQL injection via network in Computer Networks - Mini Project: Build & Apply

Understanding SQL Injection via Network

📖 Scenario: You are a network security analyst learning about how attackers can exploit SQL injection vulnerabilities through network requests. Understanding this helps protect systems from unauthorized data access.

🎯 Goal: Build a simple step-by-step explanation of how SQL injection can happen via network communication, using a clear example of a vulnerable query and how an attacker might exploit it.

📋 What You'll Learn

Create a sample SQL query string vulnerable to injection

Define a malicious input string that an attacker might send over the network

Show how the malicious input modifies the original query

Explain the final impact of the injection on the database query

💡 Why This Matters

🌍 Real World

Network security analysts use this knowledge to identify and prevent attacks that exploit SQL injection vulnerabilities over network connections.

💼 Career

Understanding SQL injection is essential for cybersecurity roles, database administrators, and developers to protect sensitive data and maintain secure systems.

1

Create a vulnerable SQL query string

Create a variable called query that holds the string "SELECT * FROM users WHERE username = '" concatenated with a variable user_input and then concatenated with "';". For now, set user_input to "admin".

Computer Networks

user_input = "admin"
query = "SELECT * FROM users WHERE username = '" + user_input + "';"
# Your code here

Need a hint?

Think of how a simple SQL query looks when searching for a username.

2

Define a malicious input simulating an attack

Change the value of user_input to the string "admin' OR '1'='1" to simulate an attacker trying to manipulate the query.

Computer Networks

user_input = "admin' OR '1'='1"
# Your code here

Need a hint?

This input tries to trick the database into returning all users by adding a condition that is always true.

3

Show how the malicious input changes the query

Create a variable called injected_query that combines the string "SELECT * FROM users WHERE username = '", the user_input, and "';" to show the full query after injection.

Computer Networks

injected_query = "SELECT * FROM users WHERE username = '" + user_input + "';"
# Your code here

Need a hint?

Show the full SQL query string that the database will receive after the attacker's input.

4

Explain the impact of the SQL injection

Create a variable called impact and assign it the string "The injected query returns all users because the condition '1'='1' is always true." to describe the effect of the injection.

Computer Networks

impact = "The injected query returns all users because the condition '1'='1' is always true."
# Your code here

Need a hint?

Explain in simple words what happens when the database runs the injected query.