Krebs on Security said both ship with a crypto-miner already installed, but customers have to opt into using the service that powers it.

Avira's FAQ on its crypto mining service is somewhat thin. For example, it doesn't specify how much NortonLifeLock gets out of the deal (NortonLifeLock keeps 15 per cent of any cryptocurrency mined by Norton Crypto). "Avira Crypto allows you to use your computer's idle time to mine the cryptocurrency Ethereum (ETH)," the FAQ explains. "Since crypto mining requires a high level of processing power, it is not suitable for users with an average computer.

Krebs wrote that even with compatible hardware, mining cryptocurrencies on your own is unrewarding.

“Your best option is to join a mining pool that shares their computer power to improve their chance of mining cryptocurrency. The rewards are then distributed evenly to all members in the pool."

Quite why AV companies think this is a good idea is anyone’s guess. All it meant to us was we uninstalled the Norton that came with the new machine and replaced it with Bull guard.