The Korea Internet & Security Agency (KISA) has issued a new report stating that 5,166 cases of ransomware were reported during the first nine month of 2017 with attacks targeting cryptocurrency markets on the rise.

The number of incidents, which KISA is attributing to North Korea, represents an almost 4-fold increase from the 1,438 that took place during the same period in 2016, reported the South Korean KISA, which suspects the attackers to be from North Korea, said the attacks included attempts in July and August to infiltrate South Korean bitcoin exchanges along with an attempt to manipulate digital wallet passwords in order to steal the cryptocurrency.

The attackers tend to favor phishing when looking for bitcoin and evidently these have proven successful as KISA estimated that about $90,000 in cryptocurrency was stolen every month from 2013 to 2015, reported