A12 and A13 Devices Face Permanent BootROM Flaw

*Security firm Paradigm Shift disclosed usbliter8, an unpatchable exploit that grants arbitrary code execution on iPhones, iPads, and Watches using A12, A13, S4, and S5 chips.*

Security researchers at Paradigm Shift released full technical details and a working proof-of-concept for usbliter8 on June 18. The exploit targets a flaw in the USB controller inside Apple’s A12 and A13 chips and their S4 and S5 variants. Because the vulnerability sits in the BootROM, also called SecureROM, it cannot be corrected by any later software update.

The BootROM is the first code executed when a device powers on. It is hard-coded into the silicon during manufacture. Any bug found there remains open for the life of the hardware. usbliter8 therefore leaves every affected unit permanently exposed to arbitrary code execution when the exploit is triggered over USB.

The flaw extends the reach of public BootROM attacks beyond the earlier checkm8 exploit, which covered devices from the iPhone 4S through the iPhone X. usbliter8 now includes the iPhone XS, XS Max, XR, and all iPhone 11 models, plus several iPad and Apple Watch units that use the S4 and S5 chips.

No mitigation exists short of hardware replacement. Apple has not issued a statement on the disclosure, and the research firm did not publish a patch or workaround.

Why it matters

Owners of A12- and A13-era devices lose the expectation that future software updates can close serious security holes. The same limitation now applies to a wider set of recent hardware than checkm8 reached. For users who keep devices for many years, the window of exposure simply stays open.

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Sources:

• 9to5Mac
• MacRumors
• AppleInsider

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