Security

The 10 security breaches
that cost companies the most money
(OWASP)

25 May 2026 · 8 min read Security

If you have a website, an online store, or any internet application, the OWASP Top 10 affects you directly — even if you've never heard the name. In this article, we explain what it is, what each point means, and most importantly, what you can do about it without being a developer.

What is OWASP?

OWASP (Open Worldwide Application Security Project) is a nonprofit foundation that has been documenting the most serious security problems in web applications since 2001. Its best-known document is the OWASP Top 10: an updated list of the ten most critical and frequent vulnerability categories in real websites.

It's not a theoretical list. It is built from real data from thousands of applications analyzed worldwide. When a security auditor reviews your website, the OWASP Top 10 is their mandatory starting point.

The 10 vulnerabilities, explained without jargon

A01
Broken Access Control
Broken Access Control

Your website doesn't properly control who can see what. A normal user could access other clients' data, the admin panel, or private files simply by changing a number in the URL.

Ask yourself: Can I see another client's invoice by changing the ID in the URL? Can anyone access /admin/?
A02
Cryptographic Failures
Cryptographic Failures

Sensitive data (passwords, cards, personal data) stored or transmitted without proper encryption. Includes websites without HTTPS, passwords saved in plain text, or unprotected databases.

Ask yourself: Does your website use HTTPS on all pages? Are passwords stored encrypted?
A03
Injection (SQL, XSS...)
Injection

The server executes malicious code because it didn't clean the data sent by the user. SQL injection can give full access to the database.

Ask yourself: Are all your website forms validated before processing?
A04
Insecure Design
Insecure Design

Security wasn't considered during the application's design. It's not a specific bug: it's an architecture that makes attacks easy because it was never meant to protect itself.

Ask yourself: Was security reviewed during development or only at the end?
A05
Security Misconfiguration
Security Misconfiguration

Exposed admin panels, error messages with visible technical info, incorrect permissions, unnecessary active services. It is the most common flaw in SME websites.

Ask yourself: Does your website show detailed errors to the public? Do you have listable directories?
A06
Outdated components
Vulnerable Components

WordPress, plugins, JavaScript libraries, frameworks... If they aren't updated, they have known and documented vulnerabilities that anyone can exploit with automated tools.

Ask yourself: When did you last update your WordPress and its plugins?
A07
Authentication failures
Auth Failures

Weak passwords allowed, no login attempt limits, non-expiring sessions, predictable tokens. It makes it easy for someone to take control of user accounts or the admin panel.

Ask yourself: Does your website limit failed login attempts? Do sessions expire?
A08
Integrity failures
Integrity Failures

The software loads external resources (scripts, libraries) without verifying they haven't been modified. An attacker could inject malicious code into an external library your website uses.

Ask yourself: Do you verify the integrity of the external scripts your site loads?
A09
No logging or monitoring
Logging Failures

Your website doesn't log who accesses what or detect anomalous behaviors. If you suffer an attack, you'll have no way to know what happened, when, or what data was compromised.

Ask yourself: Do you have access logs? Do you get alerts for strange behavior?
A10
Server-Side Request Forgery
SSRF

Your website makes requests to external URLs based on user data, without filtering them. An attacker can use this to access internal systems, cloud metadata, or services that shouldn't be accessible.

Ask yourself: Does your website make requests to user-provided URLs?

What can I do as a company manager?

You don't need to be technical to make the right decisions about your website's security. These are the most important actions:

  • Demand your developer or agency follow OWASP guidelines during development, not just at the end.
  • Hire a web security audit before launching any critical project or when it hasn't been reviewed in over a year.
  • Make sure your website has HTTPS on all pages, not just at checkout.
  • Keep your CMS (WordPress, Prestashop...) and all plugins updated. Every update fixes vulnerabilities.
  • Enable Two-Factor Authentication (2FA) on all admin panels.

Want to know if your website has any of these vulnerabilities?

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