20.3.8. Business logic errors

20.3. Application Attacks

Business Logic Errors

A flaw in the design or implementation of an application's business rules that lets a user:

- Bypass rules

- Gain unintended benefits

- Cause financial loss or integrity issues

🧪 Real-World Example: Business Logic Errors

- You promote one post for $1

- Cancel midway

- System lets you promote all posts for $1 instead of charging $1/post

🛑 Integrity broken due to bad logic in billing system

❗Why it matters for Security+: Business Logic Errors

- It’s a non-technical vulnerability (often missed by scanners)

- Can cause fraud, abuse, and privilege violations

- Requires manual testing and good knowledge of how the system is supposed to work

Because it's about the rules, automated scanners often miss it, requiring a human to figure out how to "trick" the system.

🛡 How to prevent it: Business Logic Errors

- Define what value looks like to the organization

- Validate logic in the design phase

- Perform manual logic testing

- Include abuse case scenarios in test plans

- Use code reviews and business process walkthroughs

A user finds a way to get multiple paid features for the price of one due to an oversight in how discounts are applied. What vulnerability is this?

Business Logic Error