Google Shares Details on Unpatched 'High Severity' macOS Kernel Flaw

Google's Project Zero team in November found a "high severity" macOS kernel flaw that was recently disclosed (via Neowin) following the expiration of a 90 day disclosure deadline.

As explained by Google, the flaw allows an attacker to modify a user-owned mounted filesystem image without informing the virtual management subsystem of the changes, meaning a hacker can tweak a file system image without user knowledge.

macbookprodesign

This copy-on-write behavior works not only with anonymous memory, but also with file mappings. This means that, after the destination process has started reading from the transferred memory area, memory pressure can cause the pages holding the transferred memory to be evicted from the page cache. Later, when the evicted pages are needed again, they can be reloaded from the backing filesystem.

This means that if an attacker can mutate an on-disk file without informing the virtual management subsystem, this is a security bug. MacOS permits normal users to mount filesystem images. When a mounted filesystem image is mutated directly (e.g. by calling pwrite() on the filesystem image), this information is not propagated into the mounted filesystem.

According to Google, Apple has not yet fixed this issue. Apple is planning to implement a fix in an upcoming software update, however.

We've been in contact with Apple regarding this issue, and at this point no fix is available. Apple are intending to resolve this issue in a future release, and we're working together to assess the options for a patch. We'll update this issue tracker entry once we have more details.

Google released the details on the bug without a fix from Apple because of its Project Zero policies. After discovering a security flaw, Project Zero provides details to the company that makes the software, providing them with 90 days to fix it before disclosure.

Google then publicly shares details on security flaws when a bug is fixed or when the 90-day deadline expires. Apple was informed of the bug in November, and the 90 day period elapsed without a fix.

Mac users should, as always, be wary of the files they're downloading to avoid attacks like this, making sure to download files only from trusted sites. It's not known if this is a bug that's easy to exploit, but Google has marked it as severe because it has the potential to bypass macOS safeguards.

Tag: Google

Top Rated Comments

StellarVixen Avatar
49 months ago
It happens when you neglect things...
Score: 25 Votes (Like | Disagree)
GrumpyMom Avatar
49 months ago
A teenager and Google trying to make Macs more secure :eek: and Apple's reported response to them looks like "talk to the hand". :confused:

What are they doing over in the spaceship? I'm not even remotely technically literate so I'm genuinely curious: is this a sign of internal mismanagement or nothing really of consequence but makes an interesting headline?
Score: 20 Votes (Like | Disagree)
quatermass Avatar
49 months ago
But, but, but... New Emojis! No really, look, over here - new emojis! And thinner too!
Score: 20 Votes (Like | Disagree)
arkitect Avatar
49 months ago
A teenager and Google trying to make Macs more secure :eek: and Apple's reported response to them looks like "talk to the hand". :confused:

What are they doing over in the spaceship? I'm not even remotely technically literate so I'm genuinely curious: is this a sign of internal mismanagement or nothing really of consequence but makes an interesting headline?
By the looks of it, running around in circles…
Score: 20 Votes (Like | Disagree)
eagle33199 Avatar
49 months ago
Out of curiosity, has Google's Project Zero disclosed unpatched issues in Google's own software? I've heard of a few directed at Apple products, but none directed at Google's own products...
Score: 13 Votes (Like | Disagree)
nate13 Avatar
49 months ago
I think the likelyhood of being exposed to this venerability is quite low (assuming they need physical possession of your hardware, to start). What brought me to the forum was to say, I'm glad for news like this. Not that venerabilities aren't bad, but because knowing there are teams identifying and resolving these issues is making a secure future for everyone. Sure, there are people who can flame Apple for not fixing sooner (I'm sure there are legitimate reasons, not some dude saying "nah, not today Google"), but that we have a culture that is pushing security is encouraging.

I'd be interested to know how many negative commenters are knowledgeable in low level kernel/ file system architecture to even reproduce the venerability, let alone patch it to an installed base of millions of users. It's so easy to critique things you don't understand.
Score: 12 Votes (Like | Disagree)

Popular Stories

General Black Friday Deals 2022 Green

All the Apple Black Friday Deals You Can Still Get

Friday November 25, 2022 4:40 am PST by
Although Black Friday is now technically over, many Apple products are still seeing major discounts through the weekend as we head into Cyber Monday. In this article, you'll find every Apple device with a notable Black Friday sale that's still available. We'll be updating as prices change and new deals arrive, so be sure to keep an eye out if you don't see the sale you're looking for yet. Note:...
iphone 14 pro hands snowflakes 1

Best Cyber Monday iPhone Deals Available Today

Wednesday November 23, 2022 1:55 pm PST by
Cellular carriers have always offered big savings on the newest iPhone models during the holidays, and Cyber Monday is no different. We're tracking notable offers on the iPhone 14 and iPhone 14 Pro devices from AT&T, Verizon, and T-Mobile. For even more savings, keep an eye on older models like the iPhone 13. Note: MacRumors is an affiliate partner with some of these vendors. When you click a...
maxresdefault

Nothing Phone 1 Displays AirPods Battery Level After Latest OS Update

Friday November 25, 2022 3:33 am PST by
Nothing Phone 1 users today began receiving the Nothing OS 1.1.7 update, which adds support for displaying the battery percentage of connected AirPods, amongst other improvements and bug fixes. If you own a Nothing Phone 1, you can check for the OTA update by going to Settings -> System -> System updates. Bear in mind that as support for displaying AirPods battery level is still an...
ipad holiday bulbs

Best Cyber Monday iPad Deals Available Today

Thursday November 24, 2022 12:25 pm PST by
Cyber Monday deals have been in full swing since Black Friday deals ended, and we're seeing solid discounts on Apple devices. We're highlighting the best sales for all of Apple's product lines, and in this article you'll find the best Cyber Monday sales on iPad, iPad Pro, iPad Air, and iPad mini. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make ...
airpods pro 2

Apple Engineer Addresses Lack of Lossless Support on New AirPods Pro

Friday November 25, 2022 2:58 am PST by
An Apple engineer has addressed the lack of lossless audio support in the second-generation AirPods Pro in a new interview. Current Bluetooth technology in the AirPods lineup means that Apple's audio products do not support Apple Music Lossless audio. Apple has previously hinted that it may develop its own codec and connectivity standard that builds on AirPlay and supports higher quality...
Cyber Monday Deals Feature 2022

Best Cyber Monday Apple Deals Still Available for AirPods, Apple TV, iPad, and More

Monday November 28, 2022 5:24 am PST by
The Black Friday and Cyber Monday holiday shopping rush is drawing to a close, but there are still some good deals to be had out there. For Apple products, many of the deals you've seen since last week are still available, though some have expired. So for anyone who missed out on Black Friday deals, there's still an opportunity to get some of the year's best prices on many Apple devices. Note: ...
Apple Watch Ultra Oceanic Plus App

Apple Announces Oceanic+ App Now Available for Apple Watch Ultra

Monday November 28, 2022 6:11 am PST by
Apple today announced that the Oceanic+ app is available for the Apple Watch Ultra starting today. Designed by Huish Outdoors in collaboration with Apple, the app serves as a dive computer for recreational scuba diving at depths up to 40 meters/130 feet. Apple already offers a basic Depth app on the Apple Watch Ultra for viewing your current depth, maximum depth reached, water temperature,...
Three Biggest iPhone SE 4 Questions Feature

Three Biggest Questions About the iPhone SE 4

Saturday November 26, 2022 12:00 am PST by
While we already have some clear indications about what to expect from the fourth-generation iPhone SE, there are three major questions looming over the device at the current time. Chinese site MyDrivers and and leaker Jon Prosser believe that the iPhone SE is set to move to an iPhone XR-like design in its next incarnation, which would involve eliminating the Home button and adding a "notch" ...