how to delete/prevent highRisk Attacks While computers idle from SAPE.heur.b19?

About every two hours for several days NIS is quaratined same attempts, but more info in history doesnt show source for me to add to block. How can I 1)delete the items from Quarantine? 2)prevent furthr attempts without knowing the source ? Since computers idle during many of these attacks, theres no way to match the origin with any activity or website.