Educational networks are definitely a vulnerable point, but it was reported a week or two ago that AOL is actually the home of the zombie PC as far as malware generated from individual ISPs goes.
Whoda thunk.
Yeah, wouldn't surprise me. I was earlier writing about my own sites' stats and the problems I've had and identified, caused by whom. I've actually done WHOIS on each and every IPA over time and the public proxies, africanet and many in Southeast Asia, the Netherlands and elsewhere around Europe is the pattern I've found.
Almost all of what I find, however, is generated from outside the U.S., but the Mexico proxies and a few of their larger domains are by far the absolute worst, most offending range.
But, all used by spammers from elsewhere, but it's dreadful to what extent Mexico's proxies allow the crud to spew.
Owners/end users are responsible for maintaining good security but what I think it probably is is that AOL makes their sales pitch (as does now Cox Communications) as an ISP based upon them providing accounts with 'security suite' softwares and such, and although it's better than nothing, it's not as current and and certainly not as uptodate and thorough as is privately purchased softwares for that purpose....so users naively rely on thier freebie 'security' offerings by the larger ISPs and don't realize they're easily infected, and thus, infect others in similar situations.
Everyone should be using, at least, Norton/Symantec for starters but many don't. And those who don't, allow all the problems to continue...every blasted infected PC then generates crud all over the internet and the harms proliferate.
I know a lot of end users claim innocence but it's really the responsibility of everyone who owns, uses a computer, to keep it secure. And not to rely on any security program that is "free" because they just pass the buck by the ISPs who provide them.