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For example , the 2016 Valentine ’s Day DDoS attacks used Shellshock , a critical vulnerability that ’s present in Linux , UNIX and Mac OS X that had been discovered more than a year earlier .
 a critical vulnerability: vulnerability; Linux: vulnerable system; UNIX: vulnerable system; Mac OS X: vulnerable system; Shellshock: vulnerability; DDoS attacks: capabilities
Given event type and trigger, please tell me the arguments of all the listed option. Output format is "name1: role1; name2: role2". 
Event type: discover vulnerability 
  Option: vulnerable system owner, vulnerability, capabilities, time, vulnerable system version, discoverer, common vulnerabilities and exposures, supported platform, vulnerable system 
Text: {0} 
Answer:
 a critical vulnerability: vulnerability; Linux: vulnerable system; UNIX: vulnerable system; Mac OS X: vulnerable system; Shellshock: vulnerability; DDoS attacks: capabilities