Guess what high end solutions they have for computers security
Or what is a computer for them?
More random speculation - I think there is a time variance between their realm and ours. So for example, 100 years of our time, might be only a few years of their time so their technology probably hasn't progressed much (if at all) while ours has advanced at a significant rate. So let's say they arrived a couple thousand years ago (our time) - perhaps to them, time has progressed very little since so their technology at that time may be very similar to what it is today. While we've had a couple thousand years of progress. So let's speculate and say they are currently 400 years ahead of us in 'tech'. That 400 years 'our time' might pass in the next few decades putting us at near parity with their technology, but to them virtually no time has passed and their still technologically similar to what they were a couple thousand years ago.Their ships and lasers would appear like magical gods 2,000 years ago, but not so much today eh? In fact, not at all..
My random guess here is they completely bypass our systems and security by using frequencies piggybacked onto our normal signals/lines. So for example if they desire to turn on and off a light in your home, which you may attribute to some supernatural force, it's actually a piggyback onto your 60Hz electrical line from some grand manipulator. Which could explain why people with 'encounters' report anomalies with technology/electronics/electrical things. Engineering wise, I suspect something that attenuates their frequency ranges would be a countermeasure, maybe like ferrite chokes on all of your lines.
All of this may be meaningless discussion. Or maybe not.