Here's the wiki re: Malware:
https://en.wikipedia.org/wiki/Malware
Fwiw, here's an old thread on the CFC Chat Forum re: warning about CFC (main) website, circa 2018 (illustrates what a pain Malware can be to cope with):
http://www.chesscanada.info/forum/sh...ut-CFC-website
An older thread, again on the CFC Chat Forum re: more of the same sort of headaches, from earlier in 2018:
http://www.chesscanada.info/forum/sh...-CFC-site-down