I'm kicking off a series of articles on API Security🔐 to help us—developers👨💻👩💻—better understand and implement secure coding in our software design. 🛡️
Here is the sixth one: Unrestricted Access to Sensitive
APIs are powerful… but with great power comes great responsibility. One major risk identified by the OWASP API Security Top 10 (2023) is the unrestricted access to sensitive business flows. Let’s break it down 👇
🔍 What’s the risk?
APIs often expose business logic that, if left unprotected, can be abused by attackers to:
- 🛒 Manipulate order flows (e.g., skipping payment)
- 🎟️ Abuse discount or promotion systems
- 🚚 Trigger expensive operations like shipping or refunds
- 💼 Access workflows not meant for regular users
📉 Why it matters:
Unlike technical vulnerabilities (like SQL injection), this issue targets business logic — the very core of your application. Attackers don’t need to hack your system; they just need to understand and manipulate the logic you exposed. It’s stealthy and hard to detect via traditional security tools.
🔐 Common examples include:
- Changing account subscription levels without authorization
- Repeating reward/redemption requests beyond limits
- Skipping necessary steps in a purchase or approval process
- Automating high-volume transactions for competitive advantage
🛡️ How to protect against it:
- ✅ Define clear access control rules for every business flow
- 🧠 Apply rate limiting and behavioral analysis to detect abuse
- 🧪 Use automated and manual testing to simulate flow manipulation
- 🧩 Add state validation to ensure each step follows the expected sequence
- 🚫 Never assume the client will behave as expected — always validate server-side
👨💼 Pro tip for devs and architects:
If your frontend can trigger a workflow, your backend must enforce business rules. The frontend is just a suggestion. The backend is the law. ⚖️
💬 Have you encountered or mitigated this type of vulnerability in your projects?
Share your experience below ⬇️
#APIsecurity #OWASP #OWASPAPI10 #CyberSecurity #BackendMatters #DevSecOps #AppSec #SecureCoding #API6 #BusinessLogic