Law enforcement officials have confirmed that hackers from North Korea sought to steal bitcoins from exchanges in South Korea.

In a report released last week, the Republic of Korea’s National Police Agency (NPA) said the incidents – which were said to be ultimately unsuccessful – did occur. It further detailed that 25 employees at four different exchanges were targeted in 10 separate “spear phishing” attempts since July.

Spear phishing is when a would-be hacker pretends to be someone else in order to trick the victim into providing login or other details.

The confirmation comes several weeks after cybersecurity firm FireEye published a report on the attacks.

AFP, citing regional news source Yonhap, reported that those behind the attacks pretended to be security specialists and sent emails with malware included as attachments. The police report further indicated that the hacking attempts also targeted smartphones, suggesting that they may have been attempting to compromise devices used for two-factor authentication.

Perhaps most notably, the NPA indicated that none of the investigated attempts resulted in either the loss of funds or an actual security breach, according to AFP. No exchanges were identified in the report.

The Permanent Mission to the United Nations of the Democratic People’s Republic of Korea did not respond to a request for comment.

North Korean soldiers image via Astrelok/Shutterstock