The KE1xF MCU counts with a ROM bootloader called MCUBoot, this bootloader is capable to use the CAN protocol to update the flash content. In the following link you can check the reference manual of the MCUBoot:
In the chapter 6.7 FlexCAN Peripheral you can find more information about this. You don't need specific CAN tools, only a host that can comunicate at 1 MHz.
