API Security: in concrete terms

TopicsAPI Penetration Testing Download PDF

TL;DR

API security is the practice of keeping the application programming interfaces behind modern products from being abused by attackers. APIs differ from classic web applications in three ways: every endpoint is independently authorized, the responses are structured data that scripts can scrape easily, and a single misconfigured endpoint often exposes orders of magnitude more data than a single misconfigured web page.

By Shubham Khandare, Delivery Manager, SecureLayer7Updated June 10, 2026

Topics

OWASP API Security Top 10 (2023): Every Risk Explained: the ten biggest API risks, with the access-control risks at the top.
What is BOLA (Broken Object Level Authorization)?: the most common API flaw, reaching data that is not yours. The API version of IDOR.
What is Broken Authentication in APIs?: token, session, and password failures that turn an API into an open door.
What is GraphQL Penetration Testing?: GraphQL adds its own attacks (introspection, batching, deep queries) that REST does not have.
API Rate Limit Bypass: Techniques and Defenses: when the wall against scraping and password-guessing turns out to have a side door.

References

[1]OWASP API Security Top 10 (2023)(OWASP)
[2]OWASP API Security Project(OWASP)
[3]MITRE ATT&CK for Enterprise(MITRE)

Related terms

Scope an API penetration test.

We test REST, GraphQL, gRPC, and webhook APIs against real attack patterns and ship findings with reproducible requests, the authorization or configuration change required, and the realistic blast radius for each.

See the methodology30-min scoping call, fixed-price proposal in 48 hours.

API security, in concrete terms.

Most modern applications are now mostly APIs with a thin user interface on top. The attack surface moved with them. APIs leak more data when they fail than the web pages they replaced.

Topics

References

Scope an API penetration test.