By IN-SOO NAM and ALASTAIR GALE
SEOUL—South Korean police are investigating one of the country’s biggest Internet shutdowns yet for evidence of a North Korean cyberattack, after simultaneous outages Wednesday paralyzed computer systems at major television networks and banks for several hours.
Servers at three TV stations, a number of commercial banks including Shinhan Bank and Nonghyup, and two insurance companies were either shut down or severely disrupted from around 2 p.m. local time, police and government officials said. Some systems were still down in the late evening.
Government and military sites weren’t affected by the attack, but the military raised its information surveillance status.
Television broadcasts continued throughout the outages and bank branches remained open, although some retail- and business-banking services were inaccessible to staff. Banks said automated teller and Internet banking operations were affected.
North vs. South
Cyberattacks on South Korean websites are often blamed on North Korea. Four cases in recent years:
March 2013 Computer systems at TV stations, banks and insurance companies brought down for several hours.
June 2012 Major newspaper Joongang Ilbo hacked; data deleted from production system.
April 2011 Agricultural cooperative Nonghyup unable to provide banking and credit-card services for a week; some customer data deleted. North Korean state media issues a rare official denial.
July 2009 Several government websites attacked, including those of the Defense Ministry, National Assembly and Blue House (president’s office).
Source: Staff reports
Speculation immediately focused on North Korea. South Korea’s communications watchdog said the attacks were caused by malicious code, but it didn’t have any evidence linking the attack to North Korea. There were reports of skulls appearing on the screens of affected computers.
North Korean state media made no comment on the incident.
Investigations into hacking attacks can take weeks or months.
“We’re looking into the cause of the shutdown, but we can’t say North Korea is behind it,” said a representative for South Korea’s president, Park Geun-hye.
Police also said it was too early to pin the blame on the North.
an Internet service provider for two of the broadcasters affected, KBS and YTN, said a hacking attack was likely the cause, but its own networks continued to function normally.
Seoul has said North Korea has been behind a series of cyberattacks in recent years, including malware incidents and “denial-of-service” attacks that inundate websites with requests for information, causing them to crash.
In previous attacks, the network of a local bank crashed in April 2011, while the website of a major newspaper was brought down in June 2012. A number of government websites were attacked in July 2009.
The South Korean government believes that at least some North Korean hackers are based in China.
News of the latest attack weighed on the local stock market, which closed down 1%.
President Park was briefed about the incident shortly after it began and instructed her staff to seek the cause of the outages.
Wednesday’s incident comes after North Korea on Friday accused the U.S. and South Korea of launching attacks against Internet servers in Pyongyang. North Korea news and propaganda websites were down or difficult to access for a few days last week.
North Korea will “never remain a passive onlooker to the enemies’ cyberattacks that have reached a very grave phase,” Pyongyang said through its official news agency on Friday.
The accusations of cyberattacks come amid a rise in tensions between the two neighbors following North Korea’s latest nuclear test in February and amid continuing annual military drills in the South.
Pyongyang has characterized the drills as a prelude to an invasion.
Write to Alastair Gale at [email protected]
A version of this article appeared March 21, 2013, on page A16 in the U.S. edition of The Wall Street Journal, with the headline: Seoul Investigates Web Shutdown.
Seoul Investigates Web Shutdown – Wall Street Journal
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