Apple's T2 Security Chip Vulnerable to Attack Via USB-C

After it was reported last week that Apple's T2 Security Chip could be vulnerable to jailbreaking, the team behind the exploit have released an extensive report and demonstration.

t2checkm8 1

Apple's custom-silicon T2 co-processor is present in newer Macs and handles encrypted storage and secure boot capabilities, as well as several other controller features. It appears that since the chip is based on an Apple A10 processor, it is vulnerable to the same "checkm8" exploit that has been used to jailbreak iOS devices.

The vulnerability allows for the hijacking of the T2's boot process to gain access to the hardware. Normally the T2 chip exits with a fatal error if it is in Device Firmware Update (DFU) mode and it detects a decryption call, but by using another vulnerability developed by team Pangu, it is possible for a hacker to circumvent this check and gain access to the T2 chip.

Once access is gained, the hacker has full root access and kernel execution privileges, although they cannot directly decrypt files stored using FileVault 2 encryption. However, because the T2 chip manages keyboard access, the hacker could inject a keylogger and steal the password used for decryption. It can also bypass the remote Activation Lock used by services such as MDM and Find My. A firmware password does not prevent this since it too requires keyboard access, which requires the T2 chip to run first.

The exploit can be achieved without user interaction and simply requires a modified USB-C cable to be inserted. By creating a specialized device "about the size of a power charger," an attacker can place a T2 chip into DFU mode, run the "checkra1n" exploit, upload a key logger, and capture all keys. macOS can be left unaltered by the jailbreak, but all keys can still be logged on Mac laptops. This is because MacBook keyboards are directly connected to the T2 and passed through to macOS.

A practical demonstration shows checkra1n being run over USB-C from a host device. The targeted Mac simply displays a black screen while the connected computer confirms that the exploit was successful.

These cables function by allowing access to special debug pins within a USB-C port for the CPU and other chips that are usually only used by Apple.

Apple has not fixed the security flaw and it appears to be unpatchable. For security purposes, the T2's SepOS custom operating system is stored directly in the chip's SEPROM, but this also prevents the exploit from being patched by Apple via a software update.

In the meantime, users can protect themselves from the exploit by keeping their Macs physically secure and avoiding the insertion of untrusted USB-C cables and devices.

Top Rated Comments

ElRojito Avatar
45 months ago

So much for a chip that's supposed to be all about security.
We all know the first priority was thwarting third party repair attempts. Working at the Genius Bar, the T2 chip was the biggest pain in my ass.
Score: 35 Votes (Like | Disagree)
otternonsense Avatar
45 months ago
So much for a chip that's supposed to be all about security.
Score: 27 Votes (Like | Disagree)
ruka.snow Avatar
45 months ago

And what are we gonna do until then? If this is an unfixable, unpatchable possible exploit, isn't it grounds for a mass product recall?
How do you pull mass product recall out of an exploit that needs direct access to the hardware? There will always be exploits in hardware and software. Next up you'll be calling for a class action nonsense.
Score: 13 Votes (Like | Disagree)
djcerla Avatar
45 months ago
There’s no such thing as a “secure” chip.

With enough time and effort, everything is hackable.
Score: 10 Votes (Like | Disagree)
Elijen Avatar
45 months ago

There’s no such thing as a “secure” chip.

With enough time and effort, everything is hackable.
In cryptography secure system does not mean unhackable. It means the time needed to hack it is reasonably high (e.g. millions of years).
Score: 9 Votes (Like | Disagree)
otternonsense Avatar
45 months ago

Apple Silicon Macs will not need T2 (or T3) chips because it will be presumably built in to the apple chips.
And what are we gonna do until then? If this is an unfixable, unpatchable possible exploit, isn't it grounds for a mass product recall?
Score: 8 Votes (Like | Disagree)

Popular Stories

reset password request iphone

Warning: Apple Users Targeted in Phishing Attack Involving Rapid Password Reset Requests

Tuesday March 26, 2024 4:34 pm PDT by
Phishing attacks taking advantage of Apple's password reset feature have become increasingly common, according to a report from KrebsOnSecurity. Multiple Apple users have been targeted in an attack that bombards them with an endless stream of notifications or multi-factor authentication (MFA) messages in an attempt to cause panic so they'll respond favorably to social engineering. An...
maxresdefault

Apple to Launch New iPad Pro and iPad Air Models in May

Thursday March 28, 2024 11:07 am PDT by
Apple will introduce new iPad Pro and iPad Air models in early May, according to Bloomberg's Mark Gurman. Gurman previously suggested the new iPads would come out in March, and then April, but the timeline has been pushed back once again. Subscribe to the MacRumors YouTube channel for more videos. Apple is working on updates to both the iPad Pro and iPad Air models. The iPad Pro models will...
Generic iOS 18 Feature Purple

iOS 18: What to Expect From 'Biggest' Update in iPhone's History

Wednesday March 27, 2024 11:10 am PDT by
At least some Apple software engineers continue to believe that iOS 18 will be the "biggest" update in the iPhone's history, according to Bloomberg's Mark Gurman. Below, we recap rumored features and changes for the iPhone. "The iOS 18 update is expected to be the most ambitious overhaul of the iPhone's software in its history, according to people working on the upgrade," wrote Gurman, in a r...
maxresdefault

Apple Announces WWDC 2024 Event for June 10 to 14

Tuesday March 26, 2024 10:02 am PDT by
Apple today announced that its 35th annual Worldwide Developers Conference is set to take place from Monday, June 10 to Friday, June 14. As with WWDC events since 2020, WWDC 2024 will be an online event that is open to all developers at no cost. Subscribe to the MacRumors YouTube channel for more videos. WWDC 2024 will include online sessions and labs so that developers can learn about new...
apple maps 3d feature

Apple Maps May Gain Custom Routes With iOS 18

Tuesday March 26, 2024 3:10 pm PDT by
Apple may be planning to add support for "custom routes" in Apple Maps in iOS 18, according to code reviewed by MacRumors. Apple Maps does not currently offer a way to input self-selected routes, with Maps users limited to Apple's pre-selected options, but that may change in iOS 18. Apple has pushed an iOS 18 file to its maps backend labeled "CustomRouteCreation." While not much is revealed...
General iOS 17 Feature Orange Purple

Apple Releases Revised Versions of iOS 17.4.1 and iPadOS 17.4.1 With Updated Build Number

Wednesday March 27, 2024 5:59 am PDT by
Apple on late Tuesday released revised versions of iOS 17.4.1 and iPadOS 17.4.1 with an updated build number of 21E237, according to MacRumors contributor Aaron Perris. The updates previously had a build number of 21E236. The revised updates are available for all iPhone and iPad models that are compatible with iOS 17 and iPadOS 17, but they can only be installed via the Finder app on macOS...
applephilschiller

Apple's Phil Schiller Works 80 Hours a Week Overseeing App Store

Wednesday March 27, 2024 2:03 pm PDT by
With the App Store and app ecosystem undergoing major changes in the European Union, The Wall Street Journal today shared a profile on App Store chief Phil Schiller, who is responsible for the App Store. Though Schiller transitioned from marketing chief to "Apple Fellow" in 2020 to take a step back from Apple and spend more time on personal projects and friends, he is reportedly working...