Vulnerability Discussion
If the system does not require Internet Sharing, support for it is nonessential and must be disabled.
The information system must be configured to provide only essential capabilities. Disabling Internet sharing helps prevent the unauthorized connection of devices, unauthorized transfer of information, and unauthorized tunneling.
Check
Verify the macOS system is configured to disable Internet Sharing with the following command:
/usr/bin/osascript -l JavaScript << EOS
$.NSUserDefaults.alloc.initWithSuiteName('com.apple.MCX')\
.objectForKey('forceInternetSharingOff').js
EOS
If the result is not "true", this is a finding.
Fix
Configure the macOS system to disable Internet Sharing by installing the "com.apple.MCX" configuration profile.