A North Korea-linked hacking group was likely behind a cyberattack on the Japanese company GMO Internet Group, according to the company's own analysis.

GMO's analysis pointed to the group because of characteristics of the malware used and other traces left by the attackers, sources close to the matter told Kyodo News.

The company appears to have already reported the matter to the government and is now working to establish the full circumstances.

Pyongyang has for years denied using state-linked cyber units for espionage and financial theft. It also categorically dismissed claims linking it to the record $6.3bn (£4.7bn) cryptocurrency heist at Binance.

Kyodo, working with security experts, found separately that five IP addresses used to visit a website claiming responsibility for the attack, immediately after it went online, matched those previously used by a North Korean hacking group.

Cybersecurity sources said the site also contained traces linked to several countries, including the US and Japan ,…