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

6 How Hackers Gain Access Direct access: Hacking software Indirect access: Internet connection Logical ports

7 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 informationIT 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 LANWAN

10 Firewall LANWAN Router Does dynamic address translation IP address IP addresses known only to the router, not to the ISP ISP

11 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

18 How Does a Computer Catch a Virus

19 Virus Macro virus Attach to documents virus Attachments

20 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, …)

22 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 program or save to disk and then scan with virus detection software

23 Sober Source: Calgary Herald

24 Virus Detection From: Subject: WARNING - VIRUS (Worm.Sober.U) IN MAIL TO YOU Date: November 25, :20:55 AM MST (CA) My

25 *** VIRUS ALERT *** Dear user, This is an automatically generated message from the University of Calgary, Department of Computer Science (CPSC). The CPSC system has detected a piece of with a virus called: Worm.Sober.U in an addressed to you from: The Subject of this was: Mail delivery failed Delivery of the original has been stopped. A copy of the message has been placed under quarantine. Please visit the CPSC Maia Mailguard system located: to view your quarantined messages. You will be required to log into this system using your CPSC address and your CPSC Login Password. For your reference, here are some selected headers from the Date: Fri, 25 Nov :20: (MST) From: (Empty if virus is known to forge sender address) To: Subject: Mail delivery failed Received: dpwtlcd.com (S f1f983b.cg.shawcable.net [ ])

26 Worm Program that travels independently over computer networks, seeking uninfected sites Replicates and starts up thousands of processes Overloads a system

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

28 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

29 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

31 Computer Security: Reducing Risks Disaster Planning backup power monitoring, alarms backup of data redundant sites or hot sites

32 Computer Security: Reducing Risks Physical Access Restrictions something you have: key, ID card you know: password, personal informationpassword you do: signature, … About you: BiometricsBiometrics

33 Passwords The most common tool for restricting access to computer systems Weakness user sustained guessing program guesses words from online dictionaries

34 Password Guidelines Don’t use real words names plurals common expressions reversal

35 Passwords Do mix letters and numbers change frequently keep secret

36 Biometrics