Which of the following solutions provides the most flexibility when testing new security controls prior to
implementation?

A.
Trusted OS

B.
Host software baselining

C.
OS hardening

D.
Virtualization

Explanation:
Virtualization is used to host one or more operating systems in the memory of a single host computer and
allows multiple operating systems to run simultaneously on the same hardware. Virtualization offers the
flexibility of quickly and easily making backups of entire virtual systems, and quickly recovering the virtual
system when errors occur. Furthermore, malicious code compromises of virtual systems rarely affect the
host system, which allows for safer testing and experimentation.
Incorrect Answers:
A: Trusted OS is an access-control feature that limits resource access to client systems that run operating
system that are known to implement specific security features.
B: Application baseline defines the level or standard of security that will be implemented and maintained
for the application. It may include requirements of hardware components, operating system versions,
patch levels, installed applications and their configurations, and available ports and services. Systems can
be compared to the baseline to ensure that the required level of security is being maintained.
C: Hardening is the process of securing a system by reducing its surface of vulnerability. Reducing the
surface of vulnerability typically includes removing or disabling unnecessary functions and features,
removing or disabling unnecessary user accounts, disabling unnecessary protocols and ports, and
disabling unnecessary services.

Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis,
2014, pp. 215-217
Stewart, James Michael, CompTIA Security+ Review Guide, Sybex, Indianapolis, 2014, pp. 37, 208, 246