What is the OWASP Top 10?

OWASP Top 10: definition and background

OWASP is an international nonprofit organization that publishes freely available guides, tools and standards for application security. Its best-known project is the Top 10 list, which is revised every few years based on data from real-world applications and a survey of experts.

The list is an awareness document: it shows where the greatest risks lie, but it is not a complete testing catalog. For systematic testing, there is also the OWASP Application Security Verification Standard (ASVS). On top of that, there are practical quick-reference guides for developers, the OWASP Cheat Sheets.

Typical risks from the OWASP Top 10

The categories describe types of vulnerabilities, not individual bugs. Broken access control currently ranks first—that is, cases where users can reach data or functions they are not authorized to access.

Such gaps often arise not from exotic attacks but from everyday mistakes: a forgotten permission check, an unvalidated input or a library that hasn’t been updated in years.

• Broken access control, such as viewing other customers’ data by changing an ID in the URL
• Injection, for example SQL injection via unvalidated form input
• Cryptographic failures such as inadequately protected passwords
• Security misconfigurations, such as publicly accessible admin interfaces
• Outdated or insecure components and dependencies
• Weak authentication and incomplete logging

Benefits and limits of the list

For businesses, the OWASP Top 10 is a practical benchmark: you can require service providers to develop and test applications with these risks in mind. Security policies and tenders also frequently refer to it.

The limits: simply ticking off the ten categories does not automatically make you secure. The list does not fully cover flaws in business logic, infrastructure vulnerabilities or social engineering. It is a starting point, not the finish line—complemented by threat analyses, regular updates and testing.

In practice, this means security requirements belong in the requirements specification from the outset. Anyone commissioning software should specify which standards it will be developed to, how dependencies will be updated and who will handle security updates after launch.

In practice: the OWASP Top 10 in everyday development

Security works best when it is built in from the start. This includes input validation and parameterized database queries, a clean permissions concept, secure default settings, automated dependency checks in the CI/CD pipeline and code reviews. Security updates are applied promptly.

An example: a customer portal displays invoices at addresses such as /invoice/1042. If a user changes the number, they must never be able to see other people’s invoices—the server has to check with every request whether the invoice belongs to the logged-in account. Nano Concepts takes the OWASP risks into account when developing web apps and APIs and checks existing applications for typical vulnerabilities.