I don't think storing credentials in the RTC memory is a good option. In that scenario, if you accidentally turn off the power to the lamp you lose the configuration (unless they add a battery/supercap backup, which might be difficult given that there is not much space and a lot of heat). I do know that by default, the ESP32 SDK stores the last used WiFi credentials on the flash memory mostly unprotected, though this can be disabled.
I am failing to see a real problem here, however. If an attacker is able to steal your light bulbs, I feel like you have bigger problems. I guess the biggest concern is that if you get burglarized you should maybe change your wifi password? More of a concern if you have some bulbs mounted outside, but that's about it.
That said, LIFX should have enabled some of the security settings of the chip. Encrypted flash and setting the read protect bits especially would make this attack much more annoying. It's cool that we could potentially flash our own firmware on these things, but it's pretty lazy from a security point of view.
I am failing to see a real problem here, however. If an attacker is able to steal your light bulbs, I feel like you have bigger problems. I guess the biggest concern is that if you get burglarized you should maybe change your wifi password? More of a concern if you have some bulbs mounted outside, but that's about it.
That said, LIFX should have enabled some of the security settings of the chip. Encrypted flash and setting the read protect bits especially would make this attack much more annoying. It's cool that we could potentially flash our own firmware on these things, but it's pretty lazy from a security point of view.