I have never quite understood this story.
1) McKinnon hacks into US government computers using unchanged default passwords on Windows systems with a default terminal server program on them and active. I can believe this. No problem. The default is on. Been there, done that myself.
2) These computers were connected to the public Internet an accessible to the entire world. I can believe that, too.
3) The US says he caused thousands of dollars worth of damage. I suppose it's possible that he trashed file systems while connected, but I doubt it and the government's case. That would be a stupid thing for him to do if he were trying to remain in stealth mode and actually find stuff. A spy tries hard not to leave footprints. I can't see how he could accidentally cause damage in terminal server mode snooping around a hard drive. Prove it.
4) While connected to these publicly accessible computers he found vast troves of UFO information.
Uh, no. That does not sound credible to me at all and he hasn't produced even one byte of it. If I'd done that I would have copied over those files to my own machine as fast as I could. BTW, he was on dial-up, not exactly a fast connection. He says this is why he doesn't have stuff, but the fact is, to see it at all, you have to effectively 'download' it. To see a jpeg, it needs to be in YOUR memory to display on YOUR screen. To see a PDF it has to download first, then it's an easy save.
The reason his story does not sound credible is because of how top secret information is handled by the government. We all know of the 'need to know' compartmentalized nature of US security. We also know that anything UFO-related has got to be rated very highly secret by the government. It's locked down. Few people know the whole story.
I have some personal knowledge of how this works. I'm not claiming detailed expertise in top secret networks, but I do have journeyman-level expertise in networks and network design. I was once a CNE (Certified Novell Engineer, not that that means anything in this day and age) and have personally designed and built many networks with as many as 500 machines and a dozen remote locations connected by anything from dial-up to Frame Relay to fiber optics. Part of the operation was an ISP with 35,000 subscribers and a hundred modems. My machines have been hacked, spit-upon, beat up, spammed, trolled, and kicked in the rear so many times that security became a full time job. I have also worked around and for the military all my working life, have held a Secret Clearance (working on Trident SSBNs), and have lots of 'friends in the biz.' I hired ex-military computer guys to help run my networks. Lots of shop talk.
The US does, of course, have network access, but 'secret stuff' is on entirely separate networks--compartmentalization in action. These networks are NOT 'connected to the public Internet' at all. They are PHYSICALLY separated. There is NO network cable that travels from the secure network to the public Internet. Access to these networks is passworded and encrypted like you wouldn't believe.
Employees who have access to this kind of network are under very strict restrictions. For example, you cannot take a cell phone or a thumb drive (or any memory device whatsoever) into a secure installation. The most secure installations have razor wire on top of chain link fences surrounding the buildings with Marine guards and several checkpoints to gain entry before you even get to a keyboard. Anything Top Secret gets stored in a safe meeting government specs, including your hard drive when you're not there. And the thing is, some of this so-called Top Secret stuff is very ho-hum. If you knew about it, your likely reaction would be, "So? What's so damn secret about this? Big deal!" Really. Most of it is just 'stuff' of little consequence.
If you are a technician with a Top Secret clearance assigned to maintain machinery in a top secret installation, and when something breaks, the entire office area is 'sanitized' before you get there. Every other piece of equipment is covered with curtains and ONLY the machine you are working on is left exposed and accessible. You walk into a cloth tunnel to fix the machine, do your thing, and leave.
Now, assming there really is secret UFO stuff the government is hiding, how likely is it that the REAL reports, pictures, analyses, and what not are lying around on machines publicly accessible via the Internet? Do you really think the most highly classified subject the US has allows real information to lie around in the shared "My Documents" folder of a GS-9 worker bee's PC in the Commerce Department? Some guy might have a Billy Meier wedding cake pic on his machine for shits and giggles, but you're not going to find ultra top secret stuff on a random sample of machines you just happened to hack into.
I think McKinnon got caught snooping around US government computers and they are coming down on him like a ton of bricks, very publicly, which makes no sense. They should spend their energy fixing their silly security holes and just ignore McKinnon and say his claims are bogus. IMO McKinnon found nothing important about UFOs on these machines. It makes no sense whatsoever.