Top 10 Vulnerabilities (OWASP 2025) Explained Simply, with Easy Memory Tricks

OWASP is a non-profit group of security experts. Every few years they publish the top 10 vulnerabilities that hurt websites and web apps the most. The latest list is from 2025.

To make it easy to remember, picture your website as a house. Each risk is one weak spot in that house.

The 10 risks, the easy way

1. Broken Access Control: the wrong keys

A guest can open the owner's bedroom. In a website: a normal user can see someone else's orders or open the admin page just by changing the URL.

Fix: check permissions on the server for every request, not just by hiding buttons.

2. Security Misconfiguration: doors left open

Default passwords, error messages showing secrets, test pages left online.

Fix: change default settings, turn off what you don't use, and hide detailed errors on the live site.

3. Software Supply Chain Failures: bad bricks from the supplier

Your house is only as strong as the bricks you buy. A hacked or outdated plugin or package puts attackers inside.

Fix: use trusted packages, keep them updated and run composer audit or npm audit.

4. Cryptographic Failures: secrets written on a postcard

Passwords or card numbers sent without HTTPS, or stored with weak hashing.

Fix: HTTPS everywhere, password_hash() for passwords, and encryption for sensitive data.

5. Injection: a visitor's note becomes an order

The user types code into a form, and your system runs it (SQL injection, XSS).

Fix: prepared statements for the database, and escape everything you print.

6. Insecure Design: a bad blueprint

The plan itself is weak. Example: "forgot password" with no limit on attempts.

Fix: before building a feature, ask "how could someone abuse this?"

7. Authentication Failures: a weak lock

Easy passwords, unlimited login tries, no two-factor login.

Fix: limit login attempts, offer 2FA and block common passwords.

8. Software or Data Integrity Failures: unchecked deliveries

You accept updates or data without checking where they came from.

Fix: only install signed updates from trusted sources, and never trust data just because it "looks" like yours.

9. Security Logging and Alerting Failures: no CCTV, no alarm

Someone breaks in and nobody notices for months.

Fix: log logins, errors and admin actions, and get alerts when something looks wrong.

10. Mishandling of Exceptional Conditions: panic in an emergency

When something unexpected happens, the app crashes, shows secrets, or worse, lets the user in anyway.

Fix: handle errors carefully, show a simple message, and when in doubt, deny access.

One sentence to remember all 10

Take the first letter of each word, in order:

Always Secure Software Carefully; Intruders Instantly Attack Sites Lacking Monitoring.

Letter	Risk	The house picture
A	Access control	Wrong keys
S	Security misconfiguration	Doors left open
S	Supply chain	Bad bricks
C	Cryptographic failures	Postcard secrets
I	Injection	Note becomes an order
I	Insecure design	Bad blueprint
A	Authentication	Weak lock
S	Software & data integrity	Unchecked deliveries
L	Logging & alerting	No CCTV
M	Mishandling exceptions	Panic in an emergency

What to do next

You don't need to fix everything today. Start with the three that cause the most damage: access control (1), settings (2) and injection (5). For PHP websites, our PHP security checklist shows the code for most of these fixes.

Want someone to check your website against the OWASP Top 10? Talk to our team.

Source: OWASP Top 10:2025