Preventing SQL Injection in PostgreSQL

1. Introduction

SQL Injection is a code injection technique that exploits security vulnerabilities in an application's software by manipulating SQL queries. This lesson focuses on understanding SQL Injection and implementing best practices for preventing it in PostgreSQL.

2. Understanding SQL Injection

SQL Injection occurs when an attacker can insert or manipulate SQL queries by injecting malicious SQL code. This can lead to unauthorized access to sensitive data, data modification, or even deletion.

3. Best Practices

1. Use Prepared Statements and Parameterized Queries
2. Implement Input Validation and Sanitization
3. Use ORM (Object-Relational Mapping) Libraries
4. Limit Database Permissions
5. Regularly Update PostgreSQL and Related Software
6. Employ Web Application Firewalls

4. Code Examples

Using Prepared Statements

import psycopg2

# Establish a database connection
connection = psycopg2.connect(
    dbname='your_db',
    user='your_user',
    password='your_password',
    host='localhost'
)

# Create a cursor object
cursor = connection.cursor()

# Use a prepared statement
user_id = 1
cursor.execute("SELECT * FROM users WHERE id = %s", (user_id,))

# Fetch the results
results = cursor.fetchall()
print(results)

# Close the connection
cursor.close()
connection.close()
            

Sanitizing Inputs

import re

# Function to sanitize user input
def sanitize_input(input_string):
    return re.sub(r'[^a-zA-Z0-9]', '', input_string)

# Example usage
user_input = "SELECT * FROM users; DROP TABLE users;"
clean_input = sanitize_input(user_input)
print(clean_input)  # Outputs: SELECT * FROM users DROP TABLE users
            

5. FAQ