A network administrator has a separate user account with rights to the domain administrator group.
However, they cannot remember the password to this account and are not able to login to the server
when needed. Which of the following is MOST accurate in describing the type of issue the administrator is
experiencing?

A.
Single sign-on

B.
Authorization

C.
Access control

D.
Authentication

Explanation:
Authentication generally requires one or more of the following:
Something you know: a password, code, PIN, combination, or secret phrase.
Something you have: a smart card, token device, or key.
Something you are: a fingerprint, a retina scan, or voice recognition; often referred to as biometrics,
discussed later in this chapter.
Somewhere you are: a physical or logical location.
Something you do: typing rhythm, a secret handshake, or a private knock.
Incorrect Answers:
A: Single sign-on is when a user is authenticated into the realm, they need not re-authenticate to access
resources on any realm entity. Authentication has not occurred in this instance.
B: Authorization occurs after authentication, and ensures that the requested activity or object access is
possible given the rights and privileges assigned to the authenticated identity. Authorization indicates
who is trusted to perform specific operations.
C: Access Control is defined as the control and management of users and their privileges and activities in
a secure environment.

Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 275-284