Commonwealth Bank of Australia's online banking operations have suffered multiple outages, sparking speculation that the bank has fallen prey to a massive Denial of Service attack by hackers.
NetBank began experiencing problems over the weekend before falling over Monday morning. The bank got the service back online early afternoon only for the system to stumble again later in the day.
CBA's Netbank has been the subject of fierce phishing activity since introducing a major upgrade last month.
Speaking to local newspapers, NetBank CEO Micahel Harte said the bank took the site offline when performance issues started to affect service quality early Monday.
"We haven't completely ruled out an attempt to do a denial of service attack," he said. "In order to be absolutely safe we have to check out whether or not this is a new form of attack and make sure that we've not only detected but prevented that attack from affecting our customer's integrity or the integrity of our servers."
But the resumption of 'normal service' later in the day failed to resolve the problems, as the bank throttled the maximum number of connections, and angry users vented their spleen in public online forums. Some customers who managed to log on in the afternoon say the site appeared to be missing recent account transactional data.