Commercial Flights Are Experiencing ‘Unthinkable’ GPS Attacks and Nobody Knows What to Do::New “spoofing” attacks resulting in total navigation failure have been occurring above the Middle East for months, which is “highly significant” for airline safety.
That just means you can’t use autoland in low visibility conditions. Modern IRUs (inertial reference unit) are highly accurate laser gyros that can use GPS for correction, but will throw out the data if it doesn’t make sense. Navigation won’t be affected much, and autoland (if used) will still rely on VHF guidance.
How do IRUs work do to give you location?
https://en.m.wikipedia.org/wiki/Dead_reckoning