South Korea claims North hacked government officials' smartphones

North Korea hacked the smartphones of senior South Korean government officials and stole call history, texts, and even voice calls, the South Korean intelligence agency has claimed.

South Korean officials' smartphones were attacked between the end of February and early March using texts to plant malicious codes, the National Intelligence Service (NIS), South Korea's counterpart to the CIA, announced following a committee meeting for national cybersecurity on Tuesday. The NIS briefed senior officials of 14 government agencies responsible for security or industries affected by the attacks.

20 percent of the attacks were successful and phone numbers of other high-level government officials saved on the targeted smartphones had also been compromised, the NIS said.

The NIS did not specify the precise scope of the attacks or who was targeted.

North Korea also attacked an unnamed security software vendor's company network and stole information. The vendor's software is currently used by 20 million South Koreans for internet banking, the NIS said. Another smaller vendor was also attacked.

"North Korea made 60,000 zombie PCs [in South Korea] last year. In January this year, they made 10,000 zombie PCs in 120 countries worldwide," said the intelligence service. "These zombie PCs can be used to attack our cyberspace at any time, if North Korea orders them to."

Attacks were also made against railway agencies, specifically control centres, the NIS added.

Tensions in the Korean peninsula are high following North Korea's nuclear weapon test last month, which forced South Korea to raise its cybersecurity level for the second time in a month. It had previously been raised in January following a string of cyber attacks allegedly made by the North.

Earlier this month, the country passed a controversial anti-terror law that was blocked in a nine day filibuster, the longest ever, in part due to the increased threat from North Korea.