Computer networks in the tiny Baltic country of Estonia were disabled two years ago in a cyber attack similar to the one that knocked out Web sites in South Korea and the U.S. on Wednesday. Here's a summary of what happened.
In April and May 2007, hackers unleashed a wave of cyber attacks that crippled dozens of government and corporate sites in Estonia, one of Europe's most wired countries. Estonian authorities traced the so-called denial of service attacks to Russia, and suggested they had been orchestrated by the Kremlin — a charge Moscow denied.
The online assault followed Estonia's decision to move a Soviet World War II memorial from downtown Tallinn on April 27, 2007, sparking furious protests from Russia's government and rioting among Estonia's ethnic Russian minority.
Experts said hundreds of thousands of computers were used in a coordinated attack against government agencies and banks.
Who did it?
Though it has not presented any conclusive evidence publicly, Estonia's government still blames Moscow for the attacks.
Earlier this year, a small group of Russian activists associated with the pro-Kremlin youth group Nashi said they were responsible. The claim has not been verified, but many Estonian experts believe it's credible.
The attacks had far-reaching consequences in Estonia and beyond. They prompted NATO to enhance its cyber-war capabilities and to establish the alliance's cyber defense research center in Tallinn in 2008.
They also motivated Estonia to call on the European Union to make cyber attacks a criminal offense.
Earlier this year, the FBI said it will permanently base a computer crime expert in Estonia to help fight international threats against computer systems — also a direct consequence of the cyber attacks in 2007.