2891
Hackers are likely exploiting the easy - to - find vulnerabilities , according to the security researcher who warned the Pentagon of the flaws months ago .
 ( discover vulnerability: warned,  Pentagon: vulnerable system owner, security researcher: discoverer, the flaws: vulnerability, months ago: 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:
 ( discover vulnerability: warned,  Pentagon: vulnerable system owner, security researcher: discoverer, the flaws: vulnerability, months ago: time) 