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July 2009 cyber attacks

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Massive cyber attack warns Ukraine to "expect the worst" amid tensions with Russia

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North Korea May Be Responsible For Cyber Attacks - Bloomberg

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North Korea suspected in cyber attack on U.S., South Korea

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China accused of cyber-attack on Microsoft - BBC News

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Washington Reacts to Cyber Attack in South Korea 북한 사이버능력 무시해선 안돼

The July 2009 cyberattacks were a series of coordinated cyberattacks against major government, news media, and financial websites in South Korea and the United States. The attacks involved the activation of a botnet—a large number of hijacked computers—that maliciously accessed targeted websites with the intention of causing their servers to overload due to the influx of traffic, known as a DDoS attack. Most of the hijacked computers were located in South Korea. The estimated number of the hijacked computers varies widely; around 20,000 according to the South Korean National Intelligence Service, around 50,000 according to Symantec's Security Technology Response group, and more than 166,000 according to a Vietnamese computer security researcher who analyzed the log files of the two servers the attackers controlled. An investigation revealed that at least 39 websites were targets in the attacks based on files stored on compromised systems.