The Bank of Spain's website hit by a distributed denial-of-service attack on Sunday which disrupted access to the site.
A spokesman for the bank told Reuters the attack didn't affect the bank's services or communications with the European Central Bank or other institutions.
"It is a denial of service attack that intermittently affects access to our website, but it has had no effect on the normal functioning of the entity," the spokesman told the newswire service.
The site was offline as of Tuesday afternoon local time and it's unclear if the site is down due to an ongoing attack, as a result of recovering from the damage of the initial attack, or even a precaution, Andrew Lloyd, president of Corero Network Security told SC Media.
"The recent guidance from the Bank of England (BoE) requires banks to have the cyber-resilience to ‘resist and recover' with a heavy emphasis on ‘resist'," Lloyd said. "The BoE guidance is a modern take on the old adage that ‘prevention is better than cure'."
Lloyd added that whatever protection the Bank of Spain had in place to resist a DoS attack has clearly proven to be insufficient to prevent this outage.