ROCHESTER, N.Y. -- Excellus Blue Cross Blue Shield is the latest victim of what the company is calling a 'sophisticated cyber attack.'

The insurance provider sent out this statement. In it, Excellus BCBS explained due to other hacks on insurance providers the company did their own investigation. It revealed BCBS' IT system was hacked back in December 2013. BCBS found out on August 5.

Anyone who had treatment in the 31-county upstate New York service areas of Excellus BCBS could be affected. But why did it take BCBS more than two years to discover the hack? Time Warner Cable News asked John Chriswell, an assistant computer science professor at the University of Rochester, to answer that question.

"I'm not surprised," Chriswell said. "The reason why is because hackers have techniques they can use to hide their traces. In my personal opinion we can be doing a lot more to defend current computing systems than how we are today," said Chriswell.

Chriswell said new ideas of how to thwart attacks need to be developed and a definition of security needs to be found. But he added it isn't easy as it seems, considering those in the industry can't just launch attacks to test systems out.

"The honest to goodness most difficulty we've had in the computer science field is defining what secure is, being able to make sure our defenses provide some level of security," Chriswell explained.

News of the hack shocked many, but for Steve Whitman he's irked.

"These hackers are just very frustrating," Whitman, an Excellus BCBS customer said. "We always have to stay one step ahead of them, but that seems it's pretty difficult to do."

“Protecting personal information is one of our top priorities and we take this issue very seriously. We have already taken aggressive steps to remediate our IT system of issues raised by this cyber attack," said BCBS' CEO Christopher Booth.

The company said the investigation as yet to show any data was taken or used. Excellus BCBS is offering those affected two years of free identity theft protection.

An informational hotline has been set up for customers with questions. That number is 1-877-589-3331.

Excellus BCBS has more information on their website.