1 Protecting Your Computer Internet Annoyances (Already done in Chapter 3) Spam Pop-ups Identity theft phishing hoaxes Spyware.
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Protecting Your Computer
Internet Annoyances (Already done in Chapter 3) Spam Pop-ups Identity theft
phishing hoaxes Spyware
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Computer Threats Cyber-crimes are
criminal acts conducted through the use of computers by Cyber-criminals.
Hacker: Anyone who unlawfully accesses a computer system
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What Hackers Do Steal information from computers:
Credit card numbers Bank account numbers
Internet packet sniffing Commit identity theft
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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
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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.
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Firewall Always on Internet service is a problem
use a router or firewall software see IT website for Firewall information
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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.
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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
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Change Your Network Name
Disable SSID Broadcast
Change the Default Password
Turn on Encryption
Implement Media Access Control
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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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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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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
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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
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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
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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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