A shocking new cyber security report estimates that a group of hackers stole $1 billion from banks around the world, including in the U.S.

Jo Ling Kent reported on "Happening Now" that it's being called an "unprecedented cyber-attack."

"In a new report shared with Fox Business, Russian computer security firm Kaspersky Lab estimates that a billion dollars may have been stolen in a sophisticated hacking by a gang of cyber criminals starting back in late 2013," Kent reported. "Kaspersky says 100 banks and financial institutions in 30 countries or more have been affected." 

Kent said that the primary victims in the attack are banks in Russia, Germany, China, Ukraine and the U.S. 

She noted that "unlike most cyber attacks, the hackers didn't expose a vulnerability from inside the system." 

"They studied the banks internal procedures," Kent explained. "They watched the employees, they recorded the process and impersonated bank employees. Then, they hacked into computers that controlled ATMs, and then they timed the release of cash at a time of day when their money launderers were ready to collect it."

Kent reported that the hackers stole $7.3 million from one ATM alone and that the group is still active. 

Watch the video above to hear Kent's full report on "Happening Now."