Information Technology Reference
In-Depth Information
encounter?
When individual processors or computers are linked to a net
work, the potential for security leaks expands significantly. The
problems already identified for single processors remain, but small
difficulties on a single processor may be used as wedges to open
wider leaks in a distributed system. In addition, some new types of
problems may arise.
Keyboard Sniffers: When you work at a computer, you typically
provide information to programs by typing at the keyboard or us
ing a mouse. In normal usage, you expect your data to go directly
to that application. Also, you may expect that data will be en
crypted before it is stored or sent to another machine.
Unfortunately, all of this potential security can be undermined if a
special type of program, called a
keyboard sniffer
, is constantly
monitoring and recording everything you do at your keyboard.
And, once a keyboard sniffer has recorded your information, it can
do whatever it wants with what it finds. For example, if you entered
a credit card number as part of shopping online, a keyboard sniffer
might have the capability of identifying that number as being an ac
count. If your computer is connected to the Internet, the keyboard
sniffer then could send that information to any designated location
in the world. Although these types of spying programs are still rela
tively uncommon, the technology currently exists for such programs
to be installed behind the scenes where you may not notice them,
but where they could record and transmit everything you have done
on the machine!
Wire Tapping: At a physical level, any network of machines must
use some medium to transmit data from one place to another. When
all electrical components are physically close to each other, commu
nication between machines can be monitored carefully by security
personnel to prevent unauthorized individuals from connecting to
the transmission medium and copying information as it is sent. As
distances between machines become longer, however, physical ob
servation becomes much more difficult, and the information is more
vulnerable. For example, exposed wires and junction boxes can be
tapped, radio waves can be intercepted, and electromagnetic fields
from electrical cables can be monitored. In the latter two cases,
someone could capture data without any physical connection to a
wire. When opportunities for eavesdropping and wire tapping like
