IBM revealed a sophisticated bank funds transfer scheme that uses a mixture of phishing, malware and phone calls to appropriate large sums of money from U.S. companies. However, credit unions appear to be unaffected for now, experts said.

"The Dyre Wolf" scheme utilizes Dyre, or Dyreza, malware to target corporate banking accounts. In addition to using "one of the most effective banking Trojans active in the wild because of its feature-rich capability," the Eastern European gang of cyber-criminals apparently has the type of expertise and backing to steal "upwards of a million dollars from unsuspecting companies," IBM Security Services said in a report posted on its website.

"The organization behind the Dyre malware campaign has not only consistently updated and maintained the malware, they have added more tricks to further their deception," the IBM unit wrote. "Social engineering via phone calls and denial of service are now part of their toolkit."