A vulnerability has been found that the installation of Internet Explorer 5 introduces in Windows NT through the Task Scheduler service. This vulnerability makes it possible for a User to become a member of the Administrators group if he/she can do an interactive logon. The Task Scheduler service is an "improved" version of the usual Schedule service - they are not the same thing. The Schedule service is replaced by the Task Scheduler when Internet Explorer 5 is installed on Windows NT. Microsoft security bulletin 51 addresses this issue and is available here.
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