The dormakaba registration units 9002 (PIN Pad Units) have an exposed UART header on the backside. The PIN pad is sending every button press to the UART interface. An attacker can use the interface to exfiltrate PINs. As the devices are explicitly built as Plug-and-Play to be easily replaced, an attacker is easily able to remove the device, install a hardware implant which connects to the UART and exfiltrates the data exposed via UART to another system (e.g. via WiFi).
Weakness
The product fails to adequately prevent the revealing of unnecessary and potentially sensitive system information within debugging messages.
Extended Description
Debug messages are messages that help troubleshoot an issue by revealing the internal state of the system. For example, debug data in design can be exposed through internal memory array dumps or boot logs through interfaces like UART via TAP commands, scan chain, etc. Thus, the more information contained in a debug message, the easier it is to debug. However, there is also the risk of revealing information that could help an attacker either decipher a vulnerability, and/or gain a better understanding of the system. Thus, this extra information could lower the “security by obscurity” factor. While “security by obscurity” alone is insufficient, it can help as a part of “Defense-in-depth”.