OWASP Top 10 Overview

The OWASP Top 10 is a ranked list of the most critical security risks facing web applications today. Security teams, auditors, and developers use it as a shared language for web security risk. The list is updated every few years based on real-world data from thousands of applications.

The Current OWASP Top 10 (2021 Edition)

  A01  Broken Access Control
  A02  Cryptographic Failures
  A03  Injection
  A04  Insecure Design
  A05  Security Misconfiguration
  A06  Vulnerable and Outdated Components
  A07  Identification and Authentication Failures
  A08  Software and Data Integrity Failures
  A09  Security Logging and Monitoring Failures
  A10  Server-Side Request Forgery (SSRF)

How the Ranking Works

OWASP collects data from security companies, bug bounty programs, and application testing reports. Each risk is scored on three factors:

  Frequency     — How often does this vulnerability appear in real apps?
  Exploitability — How easy is it for an attacker to use it?
  Impact        — How much damage does a successful attack cause?

A01 Broken Access Control jumped to the top position in 2021 because it appeared in 94% of tested applications — an alarming rate that signals a widespread development habit problem.

Quick Visual Map of the Top 10

  ATTACKER
     |
     |--[A03 Injection]---------------> Sends malicious data to server
     |--[A07 Auth Failures]----------> Guesses or steals login credentials
     |--[A01 Broken Access Control]--> Accesses data they are not allowed to see
     |--[A10 SSRF]------------------> Tricks server into making internal requests
     |
  SERVER / APP
     |--[A05 Misconfiguration]-------> Default passwords, open debug ports
     |--[A06 Outdated Components]----> Known bugs in old libraries
     |--[A04 Insecure Design]--------> Flawed architecture from the start
     |
  DATA LAYER
     |--[A02 Crypto Failures]--------> Passwords stored in plain text
     |--[A09 No Logging]-------------> Attacks happen undetected
     |--[A08 Integrity Failures]-----> Tampered updates or pipelines

Why This List Matters for You

Regulators and compliance frameworks reference the OWASP Top 10 directly. PCI-DSS (payment security) and SOC 2 both expect teams to address these risks. Job postings for security engineers and penetration testers list OWASP knowledge as a required skill.

How This Course Covers the Top 10

Each major risk in the Top 10 gets its own dedicated topic in this course. You will learn what the vulnerability is, how an attacker exploits it, and what developers do to prevent it. By the end of this course you will have hands-on understanding of all ten risks.

A Note on Scope

The Top 10 covers web applications specifically. OWASP also publishes separate Top 10 lists for mobile applications, APIs, and cloud-native systems — but this course focuses on the core web application list, which is the most widely applied.

Key Takeaway

The OWASP Top 10 is the security industry's most widely used framework for web risk. Knowing it prepares you to build, test, and defend real applications against the attacks attackers actually use.