South Korea's Spy Agency Reveals North Korea Hacked Phones of Government Officials

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North Korea successfully hacked the smartphones of around a dozen South Korean officials, gaining access to phone conversations, text messages, and other sensitive information, Seoul's spy agency said on Tuesday.

South Korea's National Intelligence Service (NIS) also detailed a number of other recent cyber attacks by North Korea that targeted the country's transport system, online banking networks, the Ministry of National Defense, and communications of 50 senior officials, according to South Korean news agency Yonhap.

The North Korean hackers reportedly sent texts to South Korean officials containing a link that would activate a virus if clicked. That malware, according to NIS, gave the North Koreans access to texts, phone records, and other data. The spy agency did not specify which officials were hit, but said the hacking attempts took place in the period between late February and early March.

According to Yonhap, North Korea unsuccessfully tried to hack phones belonging to the South Korean Foreign Minister Yun Byung-se, Defense Minister Han Min-koo, and National Security Adviser Kim Kwan-jin.

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South Korean President Park Geun-hye, meanwhile, is urging the country's parliament to adopt sweeping new legislation to counter the North's cyber attacks. The proposal would establish an anti-espionage unit that would report to NIS, coordinate surveillance, and give the spy agency the authority to monitor private communications.

South Korean and American officials have repeatedly expressed growing concern about Pyongyang's ability to carry out cyber attacks. Last year, according to NIS, North Korea turned 60,000 computers in the South and abroad into "zombies," meaning they successfully accessed the machines remotely and gained control over them. The spy agency reportedly claimed that North Korean hackers were in control more than 10,000 "zombie computers" in more than 120 countries in January alone.

NIS officials also alleged on Tuesday that North Korea had tried to hack into email accounts belonging to employees of South Korea's railways, reportedly with the idea of waging a cyberattack on the country's transport system. In a statement, NIS said they foiled the plot by preemptively shutting down the official email addresses of some transportation workers. The agency did not specify if the attack was directed at overland railways or city subway systems.

Officials also said Tuesday that unidentified hackers accessed a dozen computers at the Ministry of National Defense last month, but assured South Koreans that no classified military information was exposed. The spy agency also noted that, in February, North Korean hackers got into the internal network of a South Korean security software company that supports an online banking system used by more than 20 million South Koreans.

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NIS said the threat of North Korean cyber attacks has been increasing, and the spy agency suspects the renewed efforts to infiltrate South Korea's online networks could be retaliation for the tough new sanctions levelled in response to Pyongyang's recent nuclear test and rocket launch.

Two months after its second nuclear test in 2009, North Korea launched a sweeping cyberattack on South Korea, targeting government websites, news sites, and financial sites. After its third nuclear test in 2013, North Korea hit South Korean media companies and financial groups. The US also blamed North Korea for a 2014 hack on Sony Pictures Entertainment.

South Korea's government said on Tuesday that it would unilaterally impose new sanctions against 40 individuals and 30 groups with suspected links to North Korea's weapons programs. Seoul officials also said they would block any vessels that had stopped at North Korean ports in the last 180 days from entering South Korean waters.

Follow Tess Owen on Twitter: @misstessowen