Indeed, there have to be exceptions like this. Otherwise malware authors could sue AV companies for infringement, which don’t seem to fit the intention of IP law.
> Otherwise malware authors could sue AV companies for infringement, which don’t seem to fit the intention of IP law.
'You may sue the AV company for $1 million; users who suffered from your malware will civilly sue for $100 billion, and the government will charge you with crimes and put you away for a decade. Your move.'
There's this fascinating (to me, anyway) line between "viruses" (including worms, Trojans, and similar malware) that antivirus programs will tackle, and adware/spyware that they usually don't.
The difference between the two is whether it not there's a corporation publicly taking credit for the program and suing antivirus companies for defamation over calling it a "virus".
Adware/spyware is limited in distribution methods and payload types by the letter of the law, but otherwise the two classes are functionally identical.