MacOS – Hardening OSX 10.11

macosSecurity

I'm following the instruction, on hardentheworld.org to harden my OS X 10.11.

When I send the following command:

sudo defaults write /System/Library/LaunchDaemons/com.apple.mDNSResponder ProgramArguments -array-add "-NoMulticastAdvertisements"

I obtain:

Could not write /System/Library/LaunchDaemons/com.apple.mDNSResponder; exiting

My question is why this error happens and how to solve it?

Best Answer

System Integrity Protection (SIP.) It locks up a variety of files to prevent malicious software from modifying it including /System. You can temporarily disable SIP, modify your files, then turn it back on if you want to have the maximum protection.

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