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Hacking APIs: Authentication Attack
APIs with weak authentication or not control in places are the best targets of attackers or bad guys, leading to unauthorized access and data breaches. This article explores common authentication vulnerabilities, demonstrates how attackers exploit them, and provide basics advice to secure your APIs effectively.
Introduction
As A App Sec Guy, Weak authentication in APIs is a major security risk, allowing attackers to access sensitive data and functionalities is a real nightmare, could you image financial APIs without proper authentication?. In this article, we’ll explore common authentication flaws, real-world exploitation techniques, and best practices for securing APIs.
Vulnerable Demo API
For this article, I have created a vulnerable API to conduct the tests. In each article, I will update the API so you can run all the tests. You can download the project from the following URL, follow the steps of Readme file.
Common Authentication Vulnerabilities
Some of the most critical authentication issues include:
- Lack of authentication: Open endpoints exposing sensitive data.
- Weak authentication mechanisms: APIs relying solely on API keys or predictable credentials.
- User enumeration: API responses leaking valid usernames.
- JWT flaws: Missing token expiration or weak signing algorithms.
How Attackers Exploit Weak Authentication
1. User Enumeration via Login Responses
APIs should return the same error message for both incorrect usernames and passwords. Otherwise, attackers can identify valid usernames.
