Mostly from downloading illegal material. If someone is not worried about breaking the law by posting illegal material they are equally not going to mind infecting it wit spyware to try to steal your personal data. Site hosting illegal material obviously will not stop posters from doing this even if the site itself does not infect them. Once pirate software starts installing and you click to allow it to change the system YOU have isntalled the spyware. This will often tell your anti-virus to leave it alone. After that, randomly opening email attachments, or even in some cases the email itself and clicking content. BIG mistake. After that are randomly following links "friends" send you, most hacking is by friends as well. Then infected web sites either deliberately set up that way to make you think you are at a legitimate site, that is the most common way of stealing your bank and credit card details including user names, passwords and security codes. Or legitimate sites which have not been careful with their security, and have been hacked, hackers infecting pages which then force download spyware onto the machine, often as part of a download or stream you actually want. And the quickest way from any sote s for you NOT to read in detail EVERY SINGLE MESSAGE that appears as you download, click options or install.
