Antivirus software is based upon code signatures. When you install some AV software, it does not come with complete, unabridged copies of every single sample an

Antivirus software is based upon code signatures. When you install some AV software, it does not come with complete, unabridged copies of every single sample and every mutation of every piece of malware ever. Not only is that a bad idea from a copyright standpoint (regardless of whether any malware author would bother to enforce their rights), but also because the AV software would completely fill up your hard drive and it would give everybody (including competitors) access to complete copies of malware.