LONDON (Reuters) - Royal Bank of Scotland said its banking platform was briefly attacked by hackers on Friday, causing problems for some customers trying to access online accounts, just days after a more serious technology crash.
RBS said a surge in internet traffic directed at its NatWest website at about 1130 GMT was a deliberate attempt to disrupt its service. The method is known as a distributed denial of service (DDoS) attack, and is a frequent occurrence at many banks.
Banks typically do not comment on such events, but RBS released a statement to customers after a system crash on Monday left more than 1 million customers unable to withdraw cash or pay for goods.
"Due to a surge in internet traffic directed at the NatWest website, customers experienced difficulties accessing some of our sites today ... at no time was there any risk to customers," RBS said.
The incident caused problems for some customers for about an hour, and RBS said its systems were now operating normally.
DDoS attacks bombard websites with huge volumes of traffic from multiple systems so they overload a server.
It can be hard to track the root of the attack and it is often not clear why the attacks take place - they may have no motive or could be a show of dissent by disgruntled customers or anti-capitalist protesters.
RBS is 82 percent owned by the UK government, and after Monday's problems its new boss Ross McEwan said the bank had neglected its technology for decades, raising concerns about the resilience of its technology.
The Bank of England's Financial Policy Committee has urged all UK banks to be more vigilant and prepare their defences against increasing cyber crime.
(Reporting by Steve Slater; Editing by Elaine Hardcastle)