Autel MaxiCharger AC Wallbox Commercial Firmware Downgrade Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Autel MaxiCharger AC Wallbox Commercial charging stations. An attacker must first obtain the ability to pair a malicious Bluetooth device with the target system in order to exploit this vulnerability.
The specific flaw exists within the firmware update process. The issue results from the lack of proper validation of a firmware image before using it to perform an upgrade. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the device. Was ZDI-CAN-26354.
Security-version number in hardware is mutable, resulting in the ability to downgrade (roll-back) the boot firmware to vulnerable code versions.
A System-on-Chip (SoC) implements secure boot or verified boot. It might support a security version number, which prevents downgrading the current firmware to a vulnerable version. Once downgraded to a previous version, an adversary can launch exploits on the SoC and thus compromise the security of the SoC. These downgrade attacks are also referred to as roll-back attacks. The security version number must be stored securely and persistently across power-on resets. A common weakness is that the security version number is modifiable by an adversary, allowing roll-back or downgrade attacks or, under certain circumstances, preventing upgrades (i.e. Denial-of-Service on upgrades). In both cases, the SoC is in a vulnerable state.