North Korea reportedly hacked into a word processor that South Korean politicians use

North Korean hackers have reportedly hacked into a word processor that's popular with the South Korean government, The Register reports.

Researchers from security company FireEye examined a vulnerability in word processor Hangul, which is popular among government employees and politicians in South Korea.

The researchers suggest that a group of hackers used a security flaw in the software to send and receive encrypted files. It's not clear exactly what the hackers were trying to get access to.

It's tricky to know for sure whether North Korea is behind the hack. Just like with the Sony Pictures hack in November, it's tough to definitively prove that North Korean hackers were behind an attack because of the unique nature of the country's internet.

Only a small number of North Korean citizens have access to the internet, and the country is believed to maintain a division of hackers outside of the country.

But FireEye researchers say that the hackers used the same software as other attacks which have been traced to North Korea. Another way that the researchers were able to tie the attack to North Korea was by examining which command and control servers were used. Hackers use servers to control their attacks, and sometimes they re-use them, making identification easier.