The Library of Congress in the US has experienced a distributed denial of service (DDoS) attack, it revealed via social media.

On July 17th, “the nation's oldest federal cultural institution” tweeted that its websites were “experiencing technical difficulties”.

It made the same message on Facebook, thanking people for their patience while it sought to fix whatever was causing its main website problems.

On the 19th, it confirmed that this was no routine malfunction - what had taken its site – and that of the US Copyright Office – offline was a DDoS attack. It stated on Facebook:

At the time of writing, it is unclear why the Library of Congress was targeted and who was behind the DDoS attack.

Last year, cloud service provider Akamai reported that DDoS attacks have more than doubled over the last 12 months.

It remains an effective tool for attackers and can keep websites offline for days. This can prevent organizations and businesses from being able to offer their services, which can be damaging financially and from a brand point of view.