Sure, but doesn't solve what he was talking about. If they're 40-50+ light years out it would take decades for any information on our systems to hit their systems. Even if they could crack it and create a virus instantly it would still take 40-50+ years to come back to our systems. That is assuming they can "only" transmit at the speed of light over dozens of light years with no signal degradation. That is a lead time of 80-100+ years. Computers barely even existed 100 years ago. Imagine where our technology will be 100 years from now.
In the movie Contact, the aliens transmitted an enigma machine hack. I wonder why it didn't work?