1

Protecting Your Computer

Internet Annoyances (Already done in Chapter 3) Spam Pop-ups Identity theft

phishing hoaxes Spyware

2

Computer Threats Cyber-crimes are

criminal acts conducted through the use of computers by Cyber-criminals.

Hacker: Anyone who unlawfully accesses a computer system

3

What Hackers Do Steal information from computers:

Credit card numbers Bank account numbers

Internet packet sniffing Commit identity theft

4

Denial of Service Attacks Web servers are sent millions of bogus

requests Overloads the system Consequently they shut down Service is denied legitimate users

5

Denial of Service Attacks Distributed denial of

service attacks use many computers

Backdoor programs Trojan horse Zombies

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How Hackers Gain Access Direct access:

Hacking software

Indirect access: Internet connection Logical ports

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Computer Safeguards: Firewalls Software programs or

hardware devices designed to close logical ports to invaders A firewall is built into Windows

XP More robust firewalls are

available from other vendors. Firewalls are critical if you

have an always-on broadband connection.

8

Firewall Always on Internet service is a problem

use a router or firewall software see IT website for Firewall information

9

Firewall Objective: to keep the internal network secure

from the outside It is a hardware device or software through which

all traffic must pass

Firewall

LAN WAN

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Firewall

LAN WAN

RouterDoes dynamic address translation

IP address

111.22.3.44

IP addresses known only to the router, not to the ISP

ISP

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Protecting a Wireless Network Wireless network range doesn’t stop at the

property line. Default device and network ID settings allow

intruders to enter the network. Internet bandwidth can be stolen Computers can be vulnerable to hacker intrusion

and takeover.

12

Secure Your Wireless Router Change Your Network Name (SSID) Disable SSID Broadcast Change the Default Password on Your Router Turn on Encryption (WAP is best) Implement Media Access Control Apply Firmware Upgrades

13

Change Your Network Name

Disable SSID Broadcast

Change the Default Password

Turn on Encryption

Implement Media Access Control

14

Software Sabotage Risks

Virus Worm Trojan horse Spyware DOS Attacks

Protection

15

Computer Threat - Viruses

A virus is a program that attaches itself to another program

It hides within the code of the host program When host program executes the virus

code executes also and copies itself to other programs

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17

What Viruses Do Replicate themselves:

Slow down networks

Secondary objectives: Annoying messages Delete files on the hard drive Change computer settings

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How Does a Computer Catch a Virus

19

Virus Macro virus

Attach to documents

Email virus Attachments

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Antivirus Software Programs designed to detect viruses:

Scan files looking for virus signatures (unique code) Provides options for deleting or fixing infected files

Detect known viruses Antivirus programs need to be updated frequently

21

Use Anti-virus Software Install and update anti-virus software

UofC IT anti-virus web page Free software: McAffee

ISP might provide free Otherwise buy it (McAffee, Norton, …)

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Email Virus Detection ISP mail server (UofC IT and CPSC)

Scans incoming and outgoing messages, notifies user if finds virus (strips attachments), and quarantines the message

User can recover message from quarantine If you suspect: don’t open the attachment

Delete the message Scan in email program or save to disk and then scan with

virus detection software

23

Sober

Source: Calgary Herald

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Email Virus Detection

From: virusalert@cpsc.ucalgary.ca

Subject: WARNING - VIRUS (Worm.Sober.U) IN MAIL TO YOU

Date: November 25, 2005 10:20:55 AM MST (CA)

My email

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*** VIRUS ALERT ***Dear user,This is an automatically generated message from the University ofCalgary, Department of Computer Science (CPSC).

The CPSC email system has detected a piece of email with a virus called: Worm.Sober.Uin an email addressed to you from:<postman@hotmail.com>The Subject of this email was:Mail delivery failedDelivery of the original email has been stopped. A copy of the message hasbeen placed under quarantine.Please visit the CPSC Maia Mailguard system located:http://imgw1.cpsc.ucalgary.ca/mailto view your quarantined messages. You will be required to log intothis system using your CPSC Email address and your CPSC Login Password.

For your reference, here are some selected headers from the email:------------------------------------------------------------------Date: Fri, 25 Nov 2005 10:20:55 -0700 (MST)From: ?@S010600112f1f983b.cg.shawcable.net (Empty if virus is known to forge sender address)To: Subject: Mail delivery failed

Received: dpwtlcd.com (S010600112f1f983b.cg.shawcable.net [68.147.104.66])

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Worm Program that travels independently over

computer networks, seeking uninfected sites

Replicates and starts up thousands of processes

Overloads a system

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The Cost of Worms Nimba, Sept. 18, 2001 In 24 h infected 2.2 million computers Microsoft Windows Huge traffic disabled web and email servers Damaged system files

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Trojan Horse Program that performs a useful task while

also being secretly destructive A logic bomb responds to a particular event Cannot replicate E.G. Logon Trojan horse

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Denial of Service Attacks Web servers are sent millions of bogus

requests Overloads the system Consequently they shut down Service is denied legitimate users

30

Protection from Viruses and Security Risks Use anti-virus software

Update frequently Use anti-spyware software Update your operating system

Automatic updates and security patches Microsoft Macintosh

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Computer Security: Reducing Risks

Disaster Planning backup power monitoring, alarms backup of data redundant sites or hot sites

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Computer Security: Reducing Risks

Physical Access Restrictions something

you have: key, ID card you know: password, personal information you do: signature, … About you: Biometrics

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Passwords The most common tool for restricting

access to computer systems Weakness

user sustained guessing

program guesses words from online dictionaries

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Password Guidelines Don’t use

real words names plurals common expressions reversal

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Passwords Do

mix letters and numbers change frequently keep secret

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Biometrics