A new wave of cyber attacks on banks?

A new wave of cyberattacks against large U.S. banks may be soon to come.

A group of hackers posted a warning online Monday that it would target Bank of America, SunTrust, PNC, and a number of other large banks as a protest.

That's exactly what happened in September, when Bank of America became the first affected in a string of website slowdowns attributed to "distributed denial of service" attacks, in which website servers are flooded by requests to slow down service for customers.

The Credit Union National Association reported Tuesday that it was a victim of a cyber attack it said targeted 30 companies and organizations on Monday. CUNA said no private data was compromised.

Industry publication Bank Info Security is launching a free webinar Wednesday called "The New Wave of DDoS Attacks: How to Prepare and Respond."

Bank of America customers around the country reported sporadic issues getting access to their online accounts on Monday, with some reports still trickling in Tuesday. A bank spokesman said the only issues Bank of America has received involved customers' browser settings.