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Kernel extension warning dialogs in macOS Catalina 10.15.4

March 25, 2020 Leave a comment

As part of macOS Catalina 10.15.4, Apple has begun displaying a new dialog window message concerning third-party kernel extensions. macOS Catalina is the last macOS to fully support the use of kernel extensions and these messages are meant to notify users of the following:

  • macOS had detected that a third-party kernel extension had been loaded.
  • The loaded kernel extension would be incompatible with an unspecified future version of macOS

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To further reinforce the message that kernel extensions are going away, Apple refers to them in the message window as “legacy system extensions”. System extensions were introduced as part of macOS Catalina and are Apple’s replacement for kernel extensions.

As of macOS 10.15.4, these messages are informational only and do not indicate that anything is wrong with the referenced third-party kernel extension. For more information, please see the link below:

https://support.apple.com/HT210999

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Blocking the messages

For a number of managed environments, these messages can be prevented from appearing. As long as a third-party kernel extension is whitelisted using an appropriate configuration profile, the message for it should not appear.

For more information about whitelisting kernel extensions using a configuration profile, please see the links below:

https://derflounder.wordpress.com/2018/04/12/whitelisting-third-party-kernel-extensions-using-profiles/
https://support.fleetsmith.com/hc/en-us/articles/360037495013-What-is-a-kernel-extension-
https://support.apple.com/guide/mdm/kernel-extension-policy-mdm88f99b98a/web

Categories: Mac administration, macOS

Disabling telemetry for Microsoft’s Visual Studio Code

March 20, 2020 1 comment

Recently, I was tasked with figuring out how to disable telemetry for Microsoft’s Visual Studio Code. Normally, you can disable telemetry in a Microsoft application through using a macOS configuration profile or by using a defaults command. In this case though, Microsoft bought Visual Studio Code along with the rest of Xamarin, and Xamarin had some different ideas on where and how to store settings.

In the case of Visual Studio Code, the command to disable telemetry is stored as a .json file in the following location:

/Users/username_here/Library/Application Support/Code/User/settings.json

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After some research and some work with an open source tool named jq, I was able to figure out how to handle disabling the telemetry setting. For more details, please see below the jump.

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Identifying which MDM server a Mac is enrolled with

March 18, 2020 Leave a comment

Every so often, you may run across a Mac which is enrolled in an MDM server which is different from the one it should be. However, if you’re checking remotely, it may be difficult to identify which one it is.

To help with this task, there is a script available which will parse the MDM enrollment profile on your Mac and identify the DNS name of the MDM server. For more details, please see below the jump.

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Jamf Pro Inventory Update and recon functions – alike, but not the same

March 13, 2020 3 comments

As part of discussing the outcome of a troubleshooting session concerning Jamf Pro and profile deployment with a teammate, I learned that the two functions that Jamf Pro uses to update its computer inventory worked in a similar fashion, but they weren’t identical.

The differences turned out to be important for profile deployment. For more details, please see below the jump.

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Apple making changes to maximum lifetime limits for SSL certificates as of September 2020

March 6, 2020 1 comment

All SSL certificates have a set amount of time which they’re good for, which means that at some point they expire. As an example, the SSL certificate currently used by www.apple.com has the following expiration date and time:

Friday, October 23, 2020 at 8:00:00 AM Eastern Daylight Time

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As of today, March 5th 2020, the maximum lifetime for publicly trusted SSL certificates is 825 days, or roughly 27 months.

Apple has announced that, starting on September 1, 2020 at 00:00 GMT/UTC, all new SSL certificates being issued by specific Root Certificate Authorities (Root CAs) must not have a maximum lifetime longer than 398 days, or roughly 13 months, in order to be accepted as a valid certificate on Apple’s iOS, iPadOS, macOS, watchOS, and tvOS operating systems.

Screen Shot 2020 03 05 at 4 27 54 PM

What certificates are affected?

This does not affect all SSL certificates. It will affect certificates issued on or after the September 1, 2020 start date by the Root CAs which are preinstalled with Apple’s iOS, iPadOS, macOS, watchOS, and tvOS operating systems.

Since these CAs are installed along with the OS, the certificates issued by these Root CAs are trusted by Apple’s OSs without any additional work needed by the end user. These Root CAs include commercial SSL vendors like Go Daddy, DigiCert and other companies.

What certificates are not affected?

Certificates issued by the specified preinstalled Root CAs before the September 1, 2020 start date are not affected. If they have a lifespan longer than 398 days, Apple will continue to accept them as valid until their set expiration date as long as they were issued prior to September 1, 2020 at 00:00 GMT/UTC.

Certificates issued by Root CAs which do not come with the operating system are also not affected. So if your company, school or institution has their own Root CAs , SSL certificates issued by those CAs are not affected by the new maximum lifetime restriction. Those CAs can continue to issue SSL certificates with lifetimes longer than 398 days.

Note: These Root CAs are not trusted by default by Apple’s operating systems. Instead, the Root CA’s root certificate would need to be installed and set as a trusted root by either the user or a system administrator.

Does this affect anyone other than Apple?

As of now, this is a unilateral move by Apple which hasn’t been adopted by other vendors. That said, Google had proposed something similar in September 2019 so it would not be surprising to see Google also adopt this at some point.

Will this affect only web browsers?

SSL certificates are used by a variety of applications and tools to help provide secure communication, so the effects of this change will not be restricted to web browsers like Safari. Non-compliant certificates may result in network services or applications failing to work properly.

Categories: iOS, Mac administration, macOS

Fixing Homebrew’s rsyslog on macOS Catalina

February 26, 2020 Leave a comment

As part of some recent testing, I needed to install rsyslog and the instructions I had referenced using Homebrew to do it. I used the following procedure to do it:

1. Set up a new VM running macOS 10.15.3 in VMware Fusion.

2. Inside the VM, open Terminal and install Homebrew by running the following command:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

3. Once Homebrew was installed, install rsyslog by running the following command:

brew install rsyslog

4. Copy a pre-configured rsyslog.conf file to /usr/local/etc/rsyslog.conf.

5. Set the following permissions on /usr/local/etc/rsyslog.conf:

File permissions

Owner: root - read, write
Group: wheel - read
Everyone: read

6. Start rsyslog by running the following command with root privileges:

brew services start rsyslog

When I checked on rsyslog though, it wasn’t running or accepting logs from remote Macs like it should be. What had happened?


Update – 3-5-2020: The problem described by this post has now been fixed:


 

For more details, please see below the jump.

Read more…

Categories: Mac administration, macOS, Unix

Creating root-level directories and symbolic links on macOS Catalina

January 18, 2020 3 comments

One of the changes which came with macOS Catalina was the introduction of a read-only root volume for the OS. For users or environments which were used to using adding directories to the root level of the boot drive, this change meant they could no longer do that.

To address this need, Apple added a new method for creating directories at the root level which leverages Apple File System’s new firmlink functionality. Firmlinks are new in macOS Catalina and are similar in function to Unix symbolic links, but instead of only allowing travel one way (from source to destination) firmlinks allow bi-directional travel.

The use of firmlinks is exclusively reserved for the OS’s own use, but Apple has also made available what are called synthetic firmlinks. These synthetic firmlinks are how the OS enables folks to create directories and symbolic links on the read-only boot volume. For more details, please see below the jump.

Read more…

Categories: Mac administration, macOS
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