The security administrator is observing unusual network behavior from a workstation. The
workstation is communicating with a known malicious destination over an encrypted tunnel. A full
antivirus scan, with an updated antivirus definition file, does not show any signs of infection.
Which of the following has happened on the workstation?

A.
Zero-day attack

B.
Known malware infection

C.
Session hijacking

D.
Cookie stealing

Explanation:
The vulnerability was unknown in that the full antivirus scan did not detect it. This is zero day
vulnerability.
A zero day vulnerability refers to a hole in software that is unknown to the vendor. This security
hole is then exploited by hackers before the vendor becomes aware and hurries to fix it—this
exploit is called a zero day attack. Uses of zero day attacks can include infiltrating malware,
spyware or allowing unwanted access to user information. The term “zero day” refers to the
unknown nature of the hole to those outside of the hackers, specifically, the developers. Once the
vulnerability becomes known, a race begins for the developer, who must protect users.