In brief: Tech support scams have been around for decades, so one would imagine that most people are now aware of them. But that hasn't stopped the FBI from issuing a warning to watch out for this old trick following an increase in the number of criminals using it.

The agency's recent public service announcement notes that the FBI has observed several instances nationwide of scammers conducting computer-technical support scams. It involves the same technique that's been used for many years: victims are contacted via phone or email by someone claiming that an annual subscription service, often a computer protection plan or a warranty, is about to renew, usually at a very high cost of between $300 and $500.

Targets are told to contact the scammers to cancel the renewal and receive a full refund. Those who do are then persuaded to download remote desktop protocol software, supposedly to help the fake tech support cancel the subscription and issue a refund. Anyone who seems unsure is usually offered extra money if they comply.

Installing the software grants the scammer full access to the victim's computer. They are then told the money has been refunded and are encouraged to log into their online banking account for confirmation. If they do, the perpetrators can steal their banking username and password.

At this point, the scammers can lock the victim out of their computer or place a black screen as they conduct unauthorized wire transfers to external bank accounts. Criminals sometimes deposit money into victims' accounts "by mistake" and ask them to correct it through a victim-initiated wire transfer or by providing additional banking information, which is used to empty accounts into foreign banks and launder money.

Readers of this site aren't going to fall for tech support scams, but perpetrators know that by using legitimate-looking URLs combined with technical terms and the threat of losing a lot of money, they might be able to trick the less tech-savvy.

We've seen several high-profile scams over the last few months. The FBI put out a warning about fake crypto investment apps in July. There was also the case of criminals sending out fake Microsoft Office USB sticks, a PayPal phishing scam, and Steam users were warned of sophisticated browser-in-browser attacks.