Archive for May 16, 2022

Monday, May 16, 2022

Apple Platform Security Guide (May 2022)

Apple (PDF):

Unless otherwise noted, this documentation covers the following operating system versions: iOS 15.4, iPadOS 15.4, macOS 12.3, tvOS 15.4, and watchOS 8.5.


Topics added:


In macOS 12.0.1 or later, every new macOS installation also installs a paired version of recoveryOS into the corresponding APFS volume group. This design is familiar to users of Intel-based Mac computers, but on a Mac with Apple silicon, it provides additional security and compatibility guarantees. Because every macOS installation now has a dedicated paired recoveryOS, this helps ensure that only that dedicated paired recoveryOS can perform security-downgrading operations. This helps protect installations of newer versions of macOS from tampering initiated from older versions of macOS, and vice versa.


To boot into a paired recoveryOS for any macOS installation, that installation needs to be selected as the default, which is done using Startup Disk in System Preferences or by starting any recoveryOS and holding Option while selecting a volume.

Howard Oakley:

Don’t be put off by its title: Apple Platform Security Guide is mandatory reading for all advanced Mac Users, and the only way we get to learn about important details of macOS, iCloud, and much else.


Indeed, several of us have experienced problems trying to get a downgraded copy of macOS on an external disk to load third-party kexts. Could this be the result of our not setting that boot volume group as “the default”?


What the Guide says currently is incorrect at the least. If M1 Recovery Mode really does have two different ways of selecting the boot volume group to be used next, their differences need to be explained properly and not left to inference and guesswork. Users, who are hardly likely to pore over the Guide or study bputil’s man page, need clear explanation of how they should start their M1 Macs from an external boot disk, how its local Recovery system is paired to it, and how to use Startup Security Utility effectively.


Update (2022-05-19): Nick Heer:

Max Zinkus tweeted a thread of notable new sections and updates, like this one[…] This is part of a broader question about whether Apple could switch any iMessage discussion to Messages for Business Chat, which has looser security and privacy standards than peer-to-peer iMessage.

iMessage itself retains a misleading description of its security architecture[…]

Update (2022-06-03): Howard Oakley:

This year, eagle-eyed readers noticed a significant absence: all mention of the Malware Removal Tool, MRT, has gone.

Studio Display Firmware 15.5

Juli Clover:

According to Apple’s release notes, the firmware refines camera tuning, offering improved noise reduction, contrast, and framing. We tested out the firmware update when it was in beta, and there is a clear difference in camera quality, mostly as it pertains to the way the framing works.

In addition to better framing, colors are not quite as pale, the contrast has been improved, and the overall look is more vibrant. Skin tones are also better than before, and there is less de-noising for more clarity, but ultimately Studio Display owners should not expect dramatic changes.

The first few comments talk about how the camera on the 24-inch iMac—a whole computer that’s thinner and costs less than the Studio Display—is better.

I don’t understand why the update requires macOS 12.4.


Update (2022-05-17): Matt J Fuller:

I ran the macOS update + #AppleStudioDisplay Firmware Update 15.5 today (took 45 min). My office has no windows so lighting did not change. I used PhotoBooth w/full-screen Screen Shots to compare. I see improvements. Before: image is more washed out. After: blacks are improved.

Gus Mueller:

Studio Display got into a loop of “updating please don’t unplug” and a warning symbol with the URL “”. It cycled between the two about 6-8 times before I just powered off the Mac and disconnected the display.

I rebooted the Mac with another display connected, waited a little bit, and reconnected the Studio Display. It tried the update again and it went through successfully this time.

Not being able to trust future display firmware updates, or my display in general, is a bummer.

Update (2022-06-16): See also: Dithering.

macOS 12.4

Juli Clover:

Universal Control is no longer in beta. It is now an official feature that Apple has deemed issue-free, and the beta labeling has been removed. Universal Control was introduced in March and it allows you to use a single mouse/trackpad and keyboard across multiple Macs and iPads.

For the Studio Display, macOS Monterey 12.4 adds support for the 15.5 firmware, which is designed to improve the webcam quality.

There’s also an update for the Podcasts app, with Apple adding a setting that limits the number of episodes stored on a Mac and automatically deletes older ones.

See also: Apple’s enterprise and security release notes.

You can download the installer here.


Update (2022-05-16): Wojciech Reguła:

My 6 vulnerabilities patched today in macOS 12.4. Let me tell you something more about them[…]

CVE-2022-26694 (Contacts) led to impersonation of entitlement that allows full control over the TCC. ☠️ Also I got keychain-access-groups for apple and apple account Keychain groups.

Update (2022-05-17): See also: Howard Oakley.

Update (2022-05-31): Howard Oakley (tweet):

If you’re thinking of upgrading from Big Sur to Monterey when Apple releases macOS 13 this autumn/fall, you might like to think twice, as there’s a major memory leak which may well remain in Monterey for ever.


When you set a Finder window into Find mode and start typing characters into its search box, the Finder launches an interactive search which homes in more narrowly as you type additional characters. What happens is that each of those searches is retained in memory, rather than being purged when a new search is started. The amount of memory used each time is determined by the number of ‘hits’ obtained at that moment. The more files that Mac has in its Spotlight database, the more hits are likely, and in some cases their number can be vast.


Update (2022-08-29): Steve Troughton-Smith:

Big news that I missed: macOS 12.4 finally fixed virtual resolutions on external monitors on Apple Silicon, meaning you can render 4K (or 1080p HiDPI) on a 1440p display again 🥳

iOS 15.5 and iPadOS 15.5

Juli Clover:

Compared to prior iOS 15 updates, iOS 15.5 and iPadOS 15.5 are smaller in scale. There are updates to the Apple Cash card in the Wallet app and a new setting that lets Podcasts users limit the number of episodes stored on their devices.

There’s a long list of security fixes.


Update (2022-05-17): Joe Cieplinski:

What’s with 15.5 having 15.4’s release notes?

Update (2022-05-19): Juli Clover:

The new updates aren’t as feature rich as the prior updates and focus primarily on under-the-hood changes, but there are still a few minor tweaks, which we’ve outlined below.