Download Viruses - Bozonline

Caring
for
Technology
Malware
Malware
In this Topic we examine:
 Viruses (or Malware)
 Virus Detection Techniques
 When a Virus is Detected
 Updating anti-virus software
Have you had a PC virus ?
What happened ?
How did you fix it ?
Computer Security Risks
A Computer security risk is…

An Action that causes loss of or damage to a
computer system
p. 556 Fig. 11-1
Computer Viruses, Worms, and Trojan Horses
Viruses, worms, and Trojan horses are:
Virus is a
potentially
damaging
computer
program
Can
spread
and
damage
files
p. 558
Worm copies
itself repeatedly,
using up
resources
and possibly
shutting down
computer or
network
Trojan horse
hides within
or looks like
legitimate
program until
triggered
Does not
replicate
itself on
other
computer
s
Payload
(destructive
event) that is
delivered when
you open file, run
infected program,
or boot computer
with infected disk
in disk drive
Computer Viruses, Worms, and Trojan Horses
How can a virus spread through an e-mail message?
Step 1. Unscrupulous
Step 2. They use
programmers create a virus
program. They hide the
virus in a Word document
and attach the Word
document to an e-mail
message.
the Internet to send
the e-mail message
to thousands of
users around the
world.
Step 3b. Other users do not
Step 3a. Some
users open the
attachment and
their computers
become infected
with the virus.
p. 559 Fig. 11-2
recognize the name of the
sender of the e-mail message.
These users do not open the
e-mail message. Instead they
delete the e-mail message.
These users’ computers are not
infected with the virus.
Computer Viruses, Worms, and Trojan Horses
To protect your system from a macro virus…

Set macro security level in applications that allow you
to write macros

At medium security
level, warning displays
that document contains
macro

p. 560 Fig. 11-3
Macros are instructions
saved in an application,
such as word processing
or spreadsheet program
Computer Viruses, Worms, and Trojan Horses
An antivirus program…


Identifies and removes
computer viruses
Most also protect against
worms and Trojan
horses
p. 560 - 561 Fig. 11-4
Computer Viruses, Worms, and Trojan Horses
A virus signature is…

A specific pattern of virus code


Also called virus definition
Antivirus programs
look for virus
signatures
p. 561 Fig. 11-5
Computer Viruses, Worms, and Trojan Horses
An antivirus program inoculates a program file by…
Recording
information
about program such
as file size and
creation
Using
date
Attempts
information
to remove
to detect if
any detected
virus tampers
virus
with file
Quarantines
infected
files that it
Keeps file
cannot
in separate
remove
area of hard disk
p. 561
Computer Viruses, Worms, and Trojan Horses
Tips to prevent virus, worm, and Trojan horse infections…
Set the macro
security in programs
so you can enable or
disable macros
If the antivirus
program flags an
e-mail attachment
as infected, delete
the attachment
immediately
p. 562
Install an antivirus
program on all of
your computers
Check all
downloaded
programs for
viruses, worms,
or Trojan horses
Never open an
e-mail attachment
unless you are
expecting it and
it is from a
trusted source
Install a personal
firewall program
Computer Viruses, Worms, and Trojan Horses
What is a denial of service attack and back door?
A denial of service attack is an assault which
disrupts access to an Internet service such as
the Web or e-mail
A back door is a program or set of instructions
in a program that allow users to bypass
security controls when accessing a computer
resource
p. 562
Computer Viruses, Worms, and Trojan Horses
Spoofing is…
Making
a network
or Internet
Transmission appear legitimate
IP spoofing occurs when an intruder
computer fools a network into
believing its IP address is from
a trusted source
Perpetrators of IP spoofing trick
their victims into interacting
with a phony
Web site
p. 563
Computer Viruses, Worms, and Trojan Horses
A firewall is…

A security system consisting of hardware and/or
software that prevents unauthorised network access
p. 563 Fig. 11-7
Computer Viruses, Worms, and Trojan Horses
A personal firewall utility is…



A program that protects personal computers and its
data from unauthorised intrusions
Monitors transmissions to and from computer
Informs you of attempted intrusion
p. 564 Fig. 11-8
Activity
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Unauthorized Access and Use
Companies protect themselves against hackers by…
Intrusion detection software
analyzes network traffic, assesses
system vulnerabilities, and identifies
intrusions and suspicious behavior
Audit trail records
access attempts
p. 564
Access control defines who
can access computer and
what actions they can take
Unauthorized Access and Use
Other ways to protect your personal computer are…

Disable file and
printer sharing on
Internet connection
File and
printer sharing
turned off
p. 565 Fig. 11-9
Unauthorized Access and Use
A user name is…


A unique set of characters that identifies a user
Password is private
combination of
characters associated
with the user name
that allows access
to computer
resources
p. 566 Fig. 11-10
Unauthorized Access and Use
Make your password more secure by…

Using longer passwords to provide greater security
p. 567 Fig. 11-11
Unauthorized Access and Use
A possessed object is…


An item that you must carry to gain access to
a computer or facility
Often used with a
numeric password
called a Personal
Identification
Number (PIN)
p. 567 Fig. 11-12
Unauthorized Access and Use
A biometric device can…

Authenticate a person’s
identity using personal
characteristics

Fingerprint, hand geometry,
voice, signature, and iris
p. 567 - 568 Fig. 11-13
Activity
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Hardware Theft and Vandalism
Hardware theft and hardware vandalism…

Hardware theft is act of stealing
computer equipment




Cables sometimes used to lock
equipment
Some notebook computers use
passwords, possessed objects, and
biometrics as security methods
For PDAs, you can passwordprotect the device
Hardware vandalism is act of
defacing or destroying computer
equipment
p. 569 Fig. 11-14
Software Theft
Software theft is…
The act of stealing or
illegally copying
software or
intentionally
erasing
programs
p. 570
Software piracy
is illegal
duplication
of copyrighted
software
Software Theft
A licence agreement gives…


You the right to use software
A standard single-user licence agreement allows users to
install software on one computer, make backup copy, and
sell software after removing from computer
p. 570 Fig. 11-15
Software Theft
Some safeguards against software theft include…
Product activation allow users to input
product identification numbers online or by
phone and receive a unique installation
identification number in return
Business Software Alliance (BSA)
promotes better understanding of
software piracy problems
p. 571
Information Theft
Encryption…




Safeguards against information theft
Is the process of converting plaintext (readable data)
into ciphertext (unreadable characters)
Encryption key (formula) often uses more than one method
To read the data, the recipient must decrypt, or decipher, the data
p. 571 - 572 Fig. 11-16
Information Theft
This is what an encrypted file looks like…
p. 573 Fig. 11-17
Activity
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Internet Security Risks
How do Web browsers provide secure data transmission?
Many Web browsers
use encryption
Secure site
– a Web site using
encryption to secure
data
Digital certificate is notice that
guarantees Web site is legitimate
p. 573
Internet Security Risks
A certificate authority (CA)…


Authorized person
or company that
issues and verifies
digital certificates
Users apply for
digital certificate
from CA
p. 573 Fig. 11-18
Internet Security Risks
Secure Sockets Layer (SSL)…

Provides encryption of all data that passes between
client and Internet server

p. 574 Fig. 11-19
Web addresses
beginning with
“https” indicate
secure connections
System Failure
A system failure…
The prolonged malfunction
of a computer
Can cause loss of hardware,
software, or data
Caused by aging hardware,
natural disasters, or electrical
power disturbances
Overvoltage or
power surge—
significant increase
in electrical power
Noise—unwanted
electrical signal
Undervoltage—drop
in electrical supply
p. 574
System Failure
A surge protector…


Protects computer and
equipment from electrical power
disturbances
Uninterruptible power supply
(UPS) is surge protector that
provides power during power loss
p. 574 - 575 Figs. 11-20–11-21
Backing Up — The Ultimate Safeguard
A backup…
Is a duplicate of file(s), program(s), or disk(s)
Full backup
all files in the
computer
Selective
backup
select
which files
to back up
Three-generation
backup
preserves
three copies
of important files
In case of system failure or corrupted files,
restore files by copying to original location
p. 576
Wireless Security
To ensuring wireless communication is secure…

Secure your wireless access point (WAP)
 WAP should not broadcast your network name
 Enable Wired Equivalent Privacy
p. 577 Fig. 11-22
Updating anti-virus software
Software needs to be continually updated since new viruses are
being written all the time
It has been suggested that up to 200 new viruses are written
every week
Most vendors of anti virus software have a website from where
you can download the most current version of their software
Activity
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