This tweet highlights a clever attack technique where attackers bypass payment validation systems by manipulating form values in web requests. Essentially, they change the price of a product from $100 to just $1 by tampering with the data sent in a POST request to the server. What's critical here is that no Web Application Firewall (WAF) can catch this attack because the manipulated request appears as valid POST data to legitimate endpoints.
WAFs typically inspect requests for known attack patterns like SQL injection, Cross-Site Scripting (XSS), Remote Code Execution (RCE), etc. However, in this case, the attack uses legitimate form data parameters but with altered values to trick the backend business logic. This means the payload consists of valid parameters and valid endpoints, so the WAF does not recognize it as malicious.
This type of attack targets the application's business logic rather than technical vulnerabilities. It emphasizes the importance of implementing strong server-side validation and authorization checks instead of relying solely on front-end validation or WAF protections.
In summary, while WAFs can help block many malicious attacks, they are not sufficient for detecting and preventing business logic attacks like payment manipulation through form value tampering. Developers should adopt layered security measures including strict server-side validation, anomaly detection, and transaction monitoring to safeguard against such threats.
Check out the original tweet here: https://twitter.com/EdgeDetectOps/status/2038043650207125855