UPDATE: The servers are back online and CCP Spielman has written a detailed developer blog about the outage.
What we can now confirm is that a person was able to utilize a vulnerability in one of the back-end services that support the operation of the Tranquility server. This vulnerability has now been secured and thoroughly tested.
We would like to stress that at no time was customer data compromised or accessible in any way.
CCP Games has taken both DUST 514 and EVE offline due to a sever DDOS attack. The team reported the outage via Twitter and have posted an update on Facebook.
Our engineers are close to resolving the issues on Tranquility. We aim to have have our servers live as soon as we possibly can. Thank you for your continued patience.
Servers are reportedly still down. We will keep you posted as the story develops.
Thanks, Coolit, for the tip!