macOS Security Updates (macSU) is a LaunchAgent and shell script for macOS 10.15 (Catalina). It will run a scan every four hours and notify the user if any of the following macOS Security components has been been updated:

• Gatekeeper
• Gatekeeper E
• Incompatible Kernel Extensions (KEXT Exclusions)
• Malware Removal Tool (MRT)
• TCC
• XProtect

Plus:

• App Exceptions
• Compatibility Notification Data
• Core LSKD (kdrl)
• Core Suggestions
• Incompatible Apps

Plus:

• System
• System build
• EFI (Boot ROM)
• iBridge
• rootless.conf

macSU now also checks against a remote database (hosted on GitHub) containing the current version numbers of the more important macOS security components. They are the first six in the list above. If any of them is outdated, the user will be notified. macSU will not notify the user when the system itself (which mostly includes EFI and iBridge) is out-of-date, to account for users who do not wish to update to a new system (immediately).

• clone repo
• chmod +x macsu.zsh && ln -s macsu.zsh /usr/local/bin/macsu.zsh
• cp local.lcars.macOSSecurityUpdates.plist $HOME/Library/LaunchAgents/local.lcars.macOSSecurityUpdates.plist
• launchctl load $HOME/Library/LaunchAgents/local.lcars.macOSSecurityUpdates.plist
• optional: install terminal-notifier

Execute macsu.zsh at least once, e.g. by running the LaunchAgent with launchctl start local.lcars.macOSSecurityUpdates, or by calling the script directly: ./macsu.zsh

Then you can test the update notification functionality i.a. by entering the following command sequence:

plutil -replace CFBundleShortVersionString -integer 2098 "$HOME/.cache/macSU/XP-version.plist" && launchctl start local.lcars.macOSSecurityUpdates

• The agent (and thereby the script) will run every 4 hours.
• macSU is only compatible with macOS 10.15 (Catalina).

• launchctl unload $HOME/Library/LaunchAgents/local.lcars.macOSSecurityUpdates.plist
• remove the cloned macOS-Security-Updates GitHub repository
• rm -f /usr/local/bin/macsu.zsh
• rm -rf $HOME/.cache/macSU
• rm -f $HOME/Library/Logs/local.lcars.macOSSecurityUpdates.log
• rm -f /tmp/local.lcars.macOSSecurityUpdates.stdout
• rm -f /tmp/local.lcars.macOSSecurityUpdates.stderr

• find a way to read the System Integrity Protection (SIP) version number on Catalina

• Howard Oakley (@hoakleyelc) of EclecticLight for providing the databases of current version numbers