Luckily I'm booted in Linux at the minute at work, so can't get spyware 😃
Just had a look on some of those hacked sites (according to Google search) and they appear to be running the following Forum software:
Snitz Forums 2000
and another example is running PostNuke. Every now and again, security exploits are found, and they are run by script kiddies who exploit this breach.
Sometimes the pages can be comprimised by the Control Panel running on the server also having an exploit. An example I've seen on another site I' help run is where there is a Java script being run from the index page, because the control panel CPANEL was out of date, and a script was able to be run.
I wouldn't worry tbh about spyware mate, the examples I've just seen of this is it's just a scrip kiddie running a scrip, and defacing the pages, nothing to worry about