Eli5 – How are computer viruses created without destroying the creator’s computer first?

Question

I’ve always wondered how computer viruses are made. If someone creates a virus on their own computer, wouldn’t it infect and potentially destroy their system first before it’s spread to others?

In: 249

Answer 1

Funnily enough there have been accidents with people handling viruses and destroying their own computer accidentally. But mostly it’s done in virtual machines, so it’s easy to rewind and do testing.

FWIW: it’s not because you have the file on your computer that you have executed it already.

Also during testing: it’s easy to add a simple test for a specific file for the malware to not do anything if it exists. That file is then created on the computer you use to build the executable to prevent it accidentally being run.