The OWASP Top 10 is a list of the most critical web application security risks, compiled by the Open Web Application Security Project (OWASP). It serves as a guide for developers, security professionals, and organizations to focus on the most pressing and common vulnerabilities that affect web applications. In this section, we will go through each of the OWASP Top 10 vulnerabilities, explaining what they are, how they work, and how to mitigate them.

Injection (e.g., SQL Injection)

Injection flaws, such as SQL Injection, occur when an attacker sends untrusted data to an interpreter as part of a command or query. The attacker’s data can trick the interpreter into executing unintended commands or accessing unauthorized data.

Example: A web application might allow users to log in by entering their username and password. If the username or password is directly included in an SQL query without proper sanitization, an attacker could inject malicious SQL code to bypass authentication.

Mitigation:

• Use prepared statements or parameterized queries to ensure that user input is treated as data, not executable code.
• Use ORM (Object-Relational Mapping) tools to abstract database queries and prevent direct user input manipulation.
• Validate and sanitize user inputs rigorously.

Broken Authentication

Broken Authentication occurs when attackers can compromise authentication mechanisms and gain unauthorized access to systems. This can happen due to weak password policies, session management vulnerabilities, or improper handling of authentication credentials.

Example: An attacker could steal a session cookie or guess weak passwords (e.g., "password123") to log in as a user or admin.

Mitigation:

• Implement multi-factor authentication (MFA) to add an extra layer of security.
• Ensure strong password policies (e.g., minimum length, complexity requirements).
• Use secure cookie attributes like HttpOnly, Secure, and session timeouts to limit the lifespan of session tokens.
• Monitor and log failed authentication attempts to detect brute force attacks.

Sensitive Data Exposure

Sensitive Data Exposure occurs when sensitive information (e.g., passwords, credit card numbers, health data) is not properly protected during storage or transmission. This could allow attackers to access personal, financial, or other sensitive data.

Example: A web application storing passwords as plain text or transmitting sensitive information over an unencrypted connection (HTTP instead of HTTPS).

Mitigation: