What is the OWASP Top 10?
The OWASP Top 10 is a regularly updated list of the most critical web application security risks, compiled from real-world breach data. It is the industry's shared checklist for "have I covered the things that actually get people hacked?"
Why it matters
Security bugs are not exotic; the same handful of mistakes cause most breaches year after year. Knowing the Top 10 means you recognize injection, broken access control, and misconfiguration in your own code before an attacker does. Every backend engineer is expected to be fluent here.
What to learn
- Broken access control and how to enforce authorization server-side
- Injection — SQL and others — and parameterization
- Cryptographic failures and protecting data in transit and at rest
- Security misconfiguration and safe defaults
- Vulnerable and outdated dependencies
- Identification and authentication failures
- Server-side request forgery and input validation
Common pitfall
Enforcing access control only in the UI — hiding a button but leaving the endpoint open. Attackers call the API directly, not your interface. Every protected action must check authorization on the server, for every request, no matter what the client shows.
Resources
Primary (free):
- OWASP — Top 10 · docs
- OWASP — Cheat sheet series · docs
- MDN — Web security · docs
Practice
Audit the API you have built against the Top 10. Pick three risks — say broken access control, injection, and misconfiguration — and verify each: confirm every protected endpoint checks authorization, every query is parameterized, and no stack traces leak. Write down one fix you made. Done when all three are closed.
Outcomes
- Name the most common web vulnerability classes.
- Enforce authorization on the server for every protected action.
- Prevent injection with parameterized queries and validation.
- Audit an API against the Top 10 and close gaps.