Xavier is a network security specialist working for a federal agency in Washington DC. Xavier is responsible for maintaining agency security policies, teaching security awareness classes, and monitoring the overall health of the network. One of Xavier’s coworkers receives a help desk call from a user who is having issues navigating to certain sites on the Internet. Xavier’s coworker cannotfigure out the issue so he hands it off to Xavier. He logs on to the user’s computer and goes to a couple of websites the user said were having issues. When Xavier types in www.Google.com, it takes him to Boogle.com instead. When Xaviertypes in Yahoo.com, it takes him to Yahooo.com instead. Xavier checks all the IP settings on the computer which are static and they appear to be correct. Xavier checks the local DNS settings as well as the DNS settings on the server and they are correct. Xavier opens a command window and types in: ipconfig /flushdns. When he navigates to the previous sites, he is still directed to the wrong ones. What issue is Xavier seeing here on the client computer?

A.
This client computer has had the hosts file poisoned.

B.
From this behavior, it is evident that the client computer’s DNS cache has been poisoned.

C.
Xavier is seeing a computer that has been infected with an IRC bot Trojan.

D.
This computer has obviously been hit by a Smurf attack.