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.

Popular Stories

iOS 18

iOS 18.4 Will Include These New Features for Your iPhone

Wednesday February 5, 2025 7:15 am PST by
iOS 18.3 was released last month, so the first iOS 18.4 beta should be coming soon. iOS 18.4 is expected to be a more substantial update for the iPhone, with several new features and changes related to Apple Intelligence and beyond. Apple's website suggests that iOS 18.4 will be released in April, following beta testing. Below, we outline what to expect from the update so far. Apple...
iCloud General Feature Redux

iPhone Users Who Pay for iCloud Storage Receive an All-New Perk

Thursday February 6, 2025 11:21 am PST by
If you pay for iCloud storage on your iPhone, Apple has a new perk for you, at no additional cost. iCloud+ is the official name for Apple's paid iCloud storage plans, which range from 50GB for $0.99 per month to 12TB for $59.99 per month in the United States. iCloud+ plans already come with multiple perks for free, such as Hide My Email and HomeKit Secure Video, and now there is another one...
maxresdefault

An Apple TV Refresh is Coming in 2025 - Here's What You Should Know

Wednesday February 5, 2025 10:17 am PST by
Apple hasn't refreshed the Apple TV since 2022, but rumors suggest that we're finally going to get an update in 2025. We don't have a full picture of what to expect yet, but we have some hints on what's coming. Subscribe to the MacRumors YouTube channel for more videos. Updated A-Series Chip The current Apple TV 4K uses the A15 Bionic chip that was in the iPhone 13 lineup, and it's time for...
iPhone SE 4 Single Camera Thumb

iPhone SE 4 Launching as Soon as Next Week

Thursday February 6, 2025 3:30 pm PST by
Apple's next-generation iPhone SE could debut as soon as next week with a launch to follow later in February, reports Bloomberg's Mark Gurman. Apple isn't expected to hold an event for the iPhone SE 4, and will instead unveil the device through a press release. The iPhone SE 4 is expected to have an iPhone 14-style design, with Apple eliminating the thick bezels and Touch ID Home button of...
iOS 18

iOS 18.3.1 Update Coming Soon for iPhones

Thursday February 6, 2025 7:31 am PST by
Apple is internally testing iOS 18.3.1 for iPhones, according to our website's analytics logs, which have been a consistently reliable indicator of upcoming iOS versions. The software update should be released within the next few weeks. iOS 18.3.1 should be a minor update that addresses software bugs and/or security vulnerabilities. Apple Intelligence notification summaries for news and...
iCloud General Feature Redux

Apple Ordered by UK to Create Global iCloud Encryption Backdoor

Friday February 7, 2025 2:37 am PST by
The British government has secretly demanded that Apple give it blanket access to all encrypted user content uploaded to the cloud, reports The Washington Post. The undisclosed order is said to have been issued last month, and requires that Apple creates a back door that allows UK security officials unencumbered access to encrypted user data worldwide – an unprecedented demand not before...
disney

Disney+ Loses 700,000 Subscribers Following Price Increase

Wednesday February 5, 2025 3:34 pm PST by
Disney+ lost 700,000 subscribers worldwide in recent months, according to Disney's earnings results for the first quarter of 2025. Disney said it now has 124.6 million Disney+ subscribers, a decrease of 0.7 million compared to its subscriber numbers in the fourth quarter of 2024. The drop in subscribers comes after Disney+ prices increased in the fall. Disney+ with Ads went from $7.99 to...
apple wallet drivers license feature iPhone 15 pro

iPhone Driver's Licenses to Expand to These 7 U.S. States

Wednesday February 5, 2025 6:27 am PST by
In select U.S. states, residents can add their driver's license or state ID to the Wallet app on the iPhone and Apple Watch, providing a convenient and contactless way to display proof of identity or age at select airports and businesses, and in select apps. Below, we outline which U.S. states and territories offer the feature, and additional states that have committed to rolling it out in...

Top Rated Comments

ElRojito Avatar
57 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
57 months ago
So much for a chip that's supposed to be all about security.
Score: 27 Votes (Like | Disagree)
ruka.snow Avatar
57 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
57 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
57 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
57 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)