A testing computer system communicates with a client computer system coupled to one or more target computer systems. The testing computer system sends test payloads to the client computer system, which are forwarded to the target computer systems. Based on the test results generated by the target computer system, the testing computer system generates a runtime payload that is executable to perform a response to a security breach identified using the test results and sends the runtime payload to the client computer platform for execution. The testing computer system receives from the client computer platform an indication of the execution of the runtime payload.