Cyberthieves using malicious software discovered by IBM Security have stolen $4 million from business customers of two dozen financial services providers this month, IBM said.

The software, called GozNym, infects devices when people it targets either click a link or open an email attachment. It remains inactive until users log into their bank accounts, when it is able to access and steal information.

"The end result is a Trojan in the wild," IBM X-Force, IBM’s security research arm, said in a blog post Thursday. IBM said GozNym was in active use and that it would continue to monitor it.

IBM Security said Friday that an analysis of the malware’s configuration file concluded that the hackers had targeted business accounts of 22 banks, credit unions and "popular e-commerce platforms" in the U.S. and two in Canada.

It did not identify any of the institutions or say how many customers were affected.