A network administrator notices that there has been an unusually high amount of network traffic on the company's internal network. The administrator has confirmed that this increase is not due to any recently added legitimate business applications or increased user activity. What should be the administrator's first step in troubleshooting this issue?
Update all network devices to the latest firmware
Verify for any unauthorized applications or users on the network
Perform a full vulnerability scan on all network devices
Schedule a system downtime to restart all devices