API Security 101 — Common Vulnerabilities and How to Prevent Them

The Unseen Gateways of Your Digital World

Imagine a major financial institution losing millions because attackers exploited a simple API vulnerability. In 2017, Equifax suffered one of the largest breaches in history due to a missed patch in their Apache Struts framework, exposing sensitive API endpoints. This isn't just a cautionary tale—it's a wake-up call.

APIs enable communication between software components. But with great power comes great responsibility. Understanding the vulnerabilities lurking in these digital corridors is crucial.

Broken Authentication

Broken authentication can allow unauthorized users to impersonate others. In the Uber breach of 2016, attackers accessed personal data by exploiting weak API authentication.

How to Test:

1. 1Use tools like Burp Suite to intercept API requests.
2. 2Manipulate authentication tokens to test unauthorized access.
3. 3Analyze responses for discrepancies.

• Implement multi-factor authentication.
• Use JWTs (JSON Web Tokens) with short expiration times.
• Regularly rotate API keys.

Excessive Data Exposure

APIs sometimes reveal more data than necessary. In 2020, a vulnerability in a popular social media platform's API exposed user data like email addresses and phone numbers.

How to Test:

• Send requests with various parameters and examine the JSON response.
• Check for unnecessary data exposure.

• Return only necessary data in API responses.
• Implement server-side data filtering.

Lack of Rate Limiting

Imagine a DDoS attack through your API. Without rate limiting, your API can be overwhelmed with requests, leading to denial of service. GitHub once faced such an issue when attackers exploited a lack of rate limiting to scrape user data.

How to Test:

• Use tools like OWASP ZAP to simulate high request volumes.
• Monitor API behavior under stress.

• Set rate limits for API clients.
• Implement account-wide quotas.
• Use API gateways for automatic throttling.

Injection Attacks

SQL and command injections are not just for web forms. APIs are vulnerable too. OWASP's 2023 report highlights injection attacks as a top API threat.

How to Test:

• Use a payload like ' OR 1=1 -- in API parameters.
• Check for unexpected behavior or data leaks.

• Use parameterized queries.
• Sanitize inputs before processing.
• Employ a web application firewall.

Broken Object Level Authorization (BOLA/IDOR)

BOLA allows attackers to manipulate identifiers to access unauthorized data. In 2019, a vulnerability in an online retailer's API exposed customer order details via IDOR.

How to Test:

• Use tools like Postman to manipulate object IDs.
• Examine the API's access control mechanisms.

• Validate user permissions for every object.
• Use UUIDs instead of sequential IDs.

How AttackVector Helps

AttackVector discovers API endpoints by scanning your application's network traffic. Tools like nmap and ffuf map out your API landscape. Once endpoints are identified, we test for weaknesses using automated scripts and manual analysis. Our reports provide detailed remediation steps, such as patching outdated libraries or tightening authorization controls.

Conclusion

APIs are essential, but they're also vulnerable. By understanding and addressing these common security flaws, you can protect your digital assets. In cybersecurity, it's not just about knowing. It's about doing.