API Security in Banking: Essential OWASP Testing

Securing Financial Data Gateways

In the Open Banking and API ecosystem, security is not optional. The OWASP API Security Top 10 standard provides the essential framework to validate that programming interfaces protect customer information.

1. Broken Object Level Authorization (BOLA)

One of the most common failures is the user-level object vulnerability. An attacker manipulates the resource identifier in the API call (e.g., changing the account ID in the endpoint `/api/accounts/123` to `/api/accounts/124`) and gains access to other users' data due to insufficient validation on the backend.

2. Data Leaks via Excessive Exposure

Many APIs return the full JSON object from the database to the client, relying on the frontend to filter out sensitive fields. This allows any attacker to read encrypted passwords, tokens, or account numbers directly from the HTTP payload.

Our Recommendation

Implement automated DAST (Dynamic Application Security Testing) scans integrated into the development pipeline to detect failures before code reaches production.