29 Which exploit can be greatly reduced by using authentication certificates on the network? Ping of death Phishing Man-in-the-middle Wiretapping 30 A network administrator receives reports that files on a company server have been altered. After inspecting various log files, the administrator determines that the damage is most likely caused by a disgruntled employee Which type of attacker is the administrator trying to find? Spoofing Insider threat Social engineering Man-in-the-middle