Three months after the websites of the nation's largest banks were incapacitated by attacks from an international group, some banks are having intermittent problems again.

During the last few weeks, the websites of several of the largest banks have been hit sporadically by so-called "distributed denial-of-service attacks." The attacks flood the websites with so much traffic that it makes it difficult for customers to log into their online accounts or get information.

Among the banks reportedly affected in recent weeks: PNC, Bank of America, JPMorgan Chase, Wells Fargo and SunTrust Bank.

Federal regulators last month warned banks nationwide about another round of DOS attacks after a group known as Izz ad-Din al-Qassam Cyber Fighters posted a statement on Dec. 10 that it planned such attacks. The group is the same one that hit the nation's largest banks in September and October -- attacking a different bank every day and going in order according to their size.

PNC has had issues off and on since about Dec. 13, according to posts on its Facebook page. As of Wednesday, "the website is operating normally and the vast majority of customers have uninterrupted access," said spokesman Fred Solomon. "If individual customers cannot access the system, we invite them to call the call center." The call center (1-888-762-2265) is open from 7 a.m. to 10 p.m. Monday through Friday and 8 a.m. to 5 p.m. Saturday and Sunday.

This round of attacks has not seemed as severe as the ones in September, which nearly paralyzed each bank's website for a day or more.

"I think that, with experience, the industry is able to be better prepared," said Lynne Woodman, spokeswoman for KeyCorp in Cleveland.

Woodman said that the industry is being vigilant about the potential for all sorts of threats, including a new blitz of phishing, in which thieves try to trick consumers into divulging information or downloading computer bugs that can compromise their personal information.

It's important for consumers to remember that banks don't send email links to customers and ask them to click on the links to update their account or open documents they weren't expecting to receive, she said.

Woodman added that customers should check on their accounts regularly -- either online, by phone or in a branch -- to thwart any kind of ongoing abuse. She personally checks on her accounts twice a week. "Nobody knows your spending patterns better than you do," she said.

There is no indication whether the web sites for any other Greater Cleveland banks besides PNC were affected by this most recent round of attacks.

Regulators say that those launching attacks may be trying to distract a bank's technology department so they can try to hack into accounts, prevent customers from reporting problems or prevent banks from sending out warnings to customers.

To reach this Plain Dealer reporter: tmurray@plaind.com

On Twitter: @teresamurray

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