1873
Ransomware scammers have been exploiting a flaw in Apple 's Mobile Safari browser in a campaign to extort fees from uninformed users .
 ( ransom: extort fees,  uninformed users: victim, Ransomware scammers: attacker, have been exploiting a flaw in Apple 's Mobile Safari browser: attack pattern) 
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: extort fees,  uninformed users: victim, Ransomware scammers: attacker, have been exploiting a flaw in Apple 's Mobile Safari browser: attack pattern) 