Under the scam, criminals with illegally gained money—often through other Internet frauds—get a company to receive cash and then forward it to an account in another country. The intent is to get around official scrutiny of financial transactions.

Money mule schemes themselves aren’t new. In the past they targeted consumers, some of whom were aware of the schemes and others taken in by a con artist. The criminals often disguised themselves as work-from-home opportunities, according to the U.S. Computer Emergency Response Team (CERT), although another popular approach was romantic interaction that starts on a dating site.

Now companies are targets, according to the Associated Press. One executive in Connecticut received an email from someone who seemed to be the small business’s owner requesting a money transfer. It was really a money mule plot targeting companies, schools, and non-profits.

“They trial and error this stuff and they see what works and they see what doesn’t,” FBI supervisory special agent James Abbott told AP.

Not only will money mule scammers try what seem to be legitimate requests, but also might try attacking computer systems for covert access to bank details.

The Department of Justice began to more heavily target money mule scams starting October 1, the agency said in a press release. It has worked to stop 400 money mules in 65 federal districts.

Potential consequences for being a money mule include frozen bank accounts, prosecution, and liability for others’ losses. The consequences can be serious, so companies should be on guard. CERT suggests companies use anti-virus and anti-spyware, limit access to sensitive data, regularly check employee lists and financial transactions, and consider isolating computers that perform banking functions from other systems.