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Cyber Assaults on Estonia Typify a New Battle Tactic

Hillar Aarelaid is part of  the country's Computer Emergency Response Team.
Hillar Aarelaid is part of the country's Computer Emergency Response Team. (By Peter Finn -- The Washington Post)

Estonia has a large number of potential targets. The economic success of the tiny former Soviet republic is built largely on its status as an "e-society," with paperless government and electronic voting. Many common transactions, including the signing of legal documents, can be done via the Internet.

The attacks began on April 27, a Friday, within hours of the war memorial's relocation. On Russian-language Internet forums, Estonian officials say, instructions were posted on how to disable government Web sites by overwhelming them with traffic, a tactic known as a denial of service attack.

The Web sites of the Estonian president, the prime minister, Parliament and government ministries were quickly swamped with traffic, shutting them down. Hackers defaced other sites, putting, for instance, a Hitler mustache on the picture of Prime Minister Andrus Ansip on his political party's Web site.

The assault continued through the weekend. "It was like an Internet riot," said Hillar Aarelaid, a lead specialist on Estonia's Computer Emergency Response Team, which headed the government's defense.

The Estonian government began blocking Internet traffic from Russia on April 30 by filtering out all Web addresses that ended in .ru.

By April 30, Aarelaid said, security experts noticed an increasing level of sophistication. Government Web sites and new targets, including media Web sites, came under attack from electronic cudgels known as botnets. Bots are computers that can be remotely commanded to participate in an attack. They can be business or home computers, and are known as zombie computers.

When bots were turned loose on Estonia, Aaviksoo said, roughly 1 million unwitting computers worldwide were employed. Officials said they traced bots to countries as dissimilar as the United States, China, Vietnam, Egypt and Peru.

By May 1, Estonian Internet service providers had come under sustained attack. System administrators were forced to disconnect all customers for 20 seconds to reboot their networks.

Newspapers in Estonia responded by closing access to their Web sites to everyone outside the country, as did the government. The sites of universities and nongovernmental organizations were overwhelmed. Parliament's e-mail service was shut for 12 hours because of the strain on servers.

Foreign governments began to take notice. NATO, the United States and the E.U. sent information technology experts. "It was a concerted, well-organized attack, and that's why Estonia has taken it so seriously and so have we," said Robert Pszczel, a NATO spokesman. Estonia is a new member of NATO and the E.U.

The FBI also provided assistance, according to Estonian officials. The bureau referred a reporter's calls to the U.S. Embassy in Estonia, which said there was no one available to discuss American assistance to the Baltic State.

On May 9, the day Russia celebrates victory in World War II, a new wave of attacks began at midnight Moscow time.

"It was the Big Bang," Aarelaid said. By his account, 4 million packets of data per second, every second for 24 hours, bombarded a host of targets that day.

"Everyone from 10-year-old boys to very experienced professionals was attacking," he said. "It was like a forest fire. It kept spreading."

By May 10, bots were probing for weaknesses in Estonian banks. They forced Estonia's largest bank to shut down online services for all customers for an hour and a half. Online banking remains closed to all customers outside the Baltic States and Scandinavia, according to Jaan Priisalu, head of the IT risk management group at Hansabank, a major Baltic bank.

"The nature of the latest attacks is very different," said Linnar Viik, a government IT consultant, "and it's no longer a bunch of zombie computers, but things you can't buy from the black market," he said. "This is something that will be very deeply analyzed, because it's a new level of risk. In the 21st century, the understanding of a state is no longer only its territory and its airspace, but it's also its electronic infrastructure.

"This is not some virtual world," Viik added. "This is part of our independence. And these attacks were an attempt to take one country back to the cave, back to the Stone Age."


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