Lol it is possible, however I dont believe this really, as he stated this used to be general pratice for linux users back in the days.
However downloading your winblows ISO's from torrent is asking for trouble.
Very likely to have malware/backdoors and whatnot.
Not if you download them freely from microdick directly
Although this may have been common practice think of why its not done anymore. You don't even need skill to add a package/script to a *nix iso and then burn it.
I am a Social Engineer, so I'm always cautious about shit like this... Not only can it contain backdoors, but stealers, monitoring programs, as well as giving this guy your address.
I'm also not say that it is, but as I said before, in the internet, good guy gregs are rare. There is always someone, somewhere that doesn't have good intentions, though to the naked eye might appear so. I have wiggled my way into staff on several sites and seeing what information I can attain. Do I do anything with this knowledge? Sometimes. Most of the time? No.
All I'm saying is be careful and you can't trust people behind a computer screen.
