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Microsoft Internet Information Services ( IIS ) 6.0 has a Zero Day vulnerability attackers leveraged last summer and is likely undergoing exploitation now , researchers said .
 researchers: discoverer; Microsoft Internet Information Services ( IIS ): vulnerable system; a Zero Day vulnerability: vulnerability; last summer: time; 6.0: vulnerable system version
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:
 researchers: discoverer; Microsoft Internet Information Services ( IIS ): vulnerable system; a Zero Day vulnerability: vulnerability; last summer: time; 6.0: vulnerable system version