The security of IoT devices greets us because of its popularization in recent years. Our daily work is to find unsafe factors on the IoT device, so it is a chance to introduce the basic exploit of a digital video record at the conference. We will start from auditing the security of web port and firmware itself, a stack overflow will be found through the debug port gotten by repacking the firmware, finally, we will use the vulnerability context to kill watchdog and getshell using the adjusted arm shellcode. We hope you would learn the knowledge of exploiting an IoT device and have fun with us to solve challenges on the road.