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A North Korean hacker group called the Lazarus Group is thought to be behind last week ’s massive ransomware attack and now it is thought a segment of this hacker group may be behind the currency mining attack .
 ( ransom: ransomware attack,  Lazarus Group: attacker, North Korean hacker group: attacker, last week: time) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: phishing, data breach, ransom, discover vulnerability, patch vulnerability, Arguments type: vulnerable system, capabilities, vulnerability, number of victim, issues addressed, compromised data, damage amount, common vulnerabilities and exposures, victim, patch number, number of data, tool, discoverer, time, purpose, place, payment method, releaser, vulnerable system version, attacker, supported platform, patch, price, vulnerable system owner, trusted entity, attack pattern. 
Text: {0} 
Answer:
 ( ransom: ransomware attack,  Lazarus Group: attacker, North Korean hacker group: attacker, last week: time) 