Ensure Internet Sharing Is Disabled

HighLevel 1Automatedmacos

Description

Internet Sharing uses the open source natd process to share an internet connection with other computers and devices on a local network. This allows the Mac to function as a router and share the connection to other, possibly unauthorized, devices. Audit: Passes when com.apple.nat has no "Enabled = 1" entry or a profile sets forceInternetSharingOff.

How it is checked

Audit method: Shell command

shell

[ -x /usr/bin/defaults ] || exit 1
f=$(/usr/bin/osascript -l JavaScript <<'EOS'
$.NSUserDefaults.alloc.initWithSuiteName('com.apple.MCX').objectForKey('forceInternetSharingOff').js
EOS
)
n=$(/usr/bin/defaults read /Library/Preferences/SystemConfiguration/com.apple.nat 2>/dev/null | /usr/bin/grep -c "Enabled = 1;")
if [ "$f" = true ] || [ "${n:-0}" -eq 0 ]; then echo compliant; else echo "Internet Sharing enabled"; fi

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Profile (preferred): com.apple.MCX forceInternetSharingOff = <true/>. Terminal: usr/bin/sudo /usr/bin/defaults write /Library/Preferences/SystemConfiguration/com.apple.nat NAT -dict Enabled -int 0. GUI: System Settings > General > Sharing > Set Internet Sharing to disabled.

Properties

Operating systems: macos-26
Tags: macossystem-settings
Reference: CIS Apple macOS 26 Tahoe Benchmark v1.1.0 - 2.3.3.7 Ensure Internet Sharing Is Disabled

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target macos