⛓️ The API chaining catastrophe
Business logic vulnerabilities
Your finance team notices discrepancies in the monthly revenue report - several enterprise customers show €0 invoices despite heavy platform usage.
Investigating the API logs, you see a sophisticated pattern: someone is using your legitimate APIs in an unexpected sequence.
They create invoices via your billing API, immediately apply maximum discounts through your promotions API, then use your customer support API to mark disputes as 'resolved' - all within milliseconds.
The attacker has discovered they can manipulate your business logic by chaining API calls in ways your system never anticipated, effectively getting premium services for free while appearing legitimate.
Technical Issue: Each individual API call is properly authenticated and authorised, but the attacker has found a way to chain legitimate API operations that circumvent business rules. Your APIs don't validate the business logic context when operations are performed in rapid succession.