April-June 2007

A series of cyberattacks on U.S. government agencies and departments results in the loss of 10 terabytes to 20 terabytes of data. That's more data than what's stored in the Library of Congress. Defense Secretary Robert Gates' unclassified e-mail account is hacked.

May 2007

Estonia's Parliament, banks, ministries and news media face "distributed denial of service," or DDoS, attacks. In DDoS attacks, Web sites are inundated with traffic, causing them to collapse. The attacks come as Estonia is in a heated dispute with Russia over the relocation of a Soviet-era war memorial. Estonian officials blame the Kremlin for the attacks.

October 2007

An e-mail sent to 1,000 staff members at the Department of Energy's Oak Ridge National Labs contains an attachment that accesses the lab's nonclassified databases.

August 2008

Hackers insert pictures of Adolf Hitler into the country of Georgia's Foreign Ministry Web site, while other government Web sites are disabled by DDoS attacks. The cyberattacks come as Russian forces engage in combat with Georgian troops. U.S. intelligence officials conclude that the Russian government was behind the attacks, perhaps acting through organized crime channels.

August-October 2008

Hackers gain access to e-mails and computer files at the presidential campaign headquarters for John McCain and Barack Obama. Investigators reportedly trace the penetrations to computers in China.

November-December 2008

Several thousand military computers at the Tampa, Fla.-based U.S. Central Command, the headquarters for military operations between east Africa and central Asia, are infected with malicious software. Investigators conclude that the malware was introduced via thumb drives that had been scattered in a parking lot.

March 2009

Researchers at the University of Toronto announce that they have discovered an extensive cyberespionage network, which they call "GhostNet." The GhostNet operators are said to have infected 1,295 host computers in 103 countries around the world. The researchers cannot conclusively identify the GhostNet operators but suspect Chinese involvement.

July 2009

Cyberattacks are launched against government, financial and media Web sites in South Korea and the U.S. Among those targeted is washingtonpost.com, the newspaper site. South Korea blames North Korea for the attacks, but the origin of the attacks is not determined.

December 2009

Google and more than 30 other U.S. companies in China are subject to significant computer attacks, resulting in the loss of technological secrets.

**Source: Center for Strategic and International Studies (Technology and Public Policy Program); news reports.