Millions of loyal World of Warcraft fans were left waiting for hours to enter the new expansion - Warlords of Draenor - after several attacks on the servers left instability and long queue times.

Blizzard Entertainment has been unable to pin-point who attacked the server, but an established hacking group, known as, DerpTrolling, has come forth to claim responsibility.

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The launch weekend servers were attacked by a heavy DDoS (denial-of-service) making it, takes hours to load for players. DDoS attacks are normally used to shut down websites, by sending mass amounts of traffic at a short time period, overriding the servers.

Normally, large groups like Blizzard - who own private servers - can defend against DDoS attacks, but it looks like this one passed through the system.

World of Warcraft is a treasured game by millions, recently regaining 10 million monthly subscribers. DerpTrolling claim its attack was done to promote better security, although a random DDoS attempt is not the best way to show lack of security.

DerpTrolling also claims to have hacked multiple online video games, including League of Legends, Eve Online, Runescape and World of Tanks. None of these have been verified, although, all have had trouble with hackers in the past.

The hacking group also claims to have 7 million usernames and passwords stored on file from various attacks. PlayStation Network and 2K accounts are the group's largest attacks. DerpTrolling claims to have 800,000 2K account usernames and passwords, and 500,000 credit/debit cards.

Comcast, Twitter, CIA, Windows Live, EA and Facebook are all on the group's portfolio of hacked companies. The CIA is interesting, DerpTrolling claims to have 1.2 million credentials belonging to the Central Intelligence Agency, an arguable figure.

All who have accounts on these various sites and services should change their passwords. Even if this is a false claim, it is not worth risking an unprotected account, and potentially getting information stolen further down the line.

TagsWorld of Warcraft, Blizzard Entertainment, Warlords of Draenor, MMO, RPG, DerpTrolling, hackers