A local security firm has issued a warning against possible North Korean cyber attacks engaging in extortion against the defense, medical and cryptocurrency sectors.

Cyber security firm ESTsecurity Corporation issued the warning on Tuesday while noting that North Korea stole cryptoassets worth some 100 million dollars from Horizon Bridge, a service run by U.S. blockchain firm Harmony.

The firm said the attacks are primarily carried out with financial objectives through the distribution of internally developed ransomware, such as Maui and Holy Ghost, while also resorting to phishing scams to plant malicious code or hack vulnerable software to steal confidential data.

It urged businesses to regularly inspect their software developers and step up monitoring and security features to prepare against such attacks.

The company also advised that the government foster more talent in the field of information security as well as establish and operate related systems jointly with the private sector.

In addition to the Horizon Bridge theft, Pyongyang also stole tokens worth 280 million dollars from cryptocurrency exchange KuCoin and over 48 million dollars from Upbit.