A Boot ROM exploit means exploiting the read-only data that is read on boot and cannot be edited, until now:
Researchers and developers can use it to dump SecureROM, decrypt keybags with AES engine, and demote the device to enable JTAG. You still need additional hardware and software to use JTAG.https://twitter.com/axi0mX/status/1177542512996544512
In his Twitter post, axi0mX describes that during the iOS 12 beta period of 2018, Apple patched a UAF (Use After Free) exploit that was found in the iBoot USB code.
He reverse engineered the patch, and discovered the vulnerability. He also said he could not be the only one who found the vulnerability.
What does a ROM Jailbreak mean for Apple iPhones?
It means you can jailbreak any iPhone, from any series, running any iOS version, permanently.
It means you can keep your phone jailbroken, without having to sideload apps every week, or sign shady Chinese Developer certificates on your device.
Apple A5 chips through to Apple A11 are exploitable.
Adversaries with physical access to the device can exploit a victims phone, permanently and with no repair option.
It is very likely that there are devices out there right now that have been exploited.
A BootROM exploit cannot be fixed. It requires physical or more access to every device.
In his closing tweet, axi0mX says:
It is a tethered bootrom exploit, but it should be possible to make a cable or a dongle that jailbreaks your device without a computer.https://twitter.com/axi0mX/status/1177739238986547200
Possible Attack Vectors using checkm8 by axi0mX
Carefully constructed USB charging ports at airports harbouring BootROM exploit
Chinese portable chargers or Raspberry Pi Zero being deployed with the exploit hardcoded into the charging port.
Works during the BOOT process and therefore does not require passcode to be entered.
All previously “bricked” iPhones may now be fully usable…
iPhone XS / XR and 11 / 11 Pro are not affected by the bootrom exploit, however almost every other iPhone certainly is, and un-patchable.