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Defending Your Computer on the Internet : Defending Your Computer on the Internet Vic Laurie Ewing SeniorNet www.vlaur.com

What Are the Problems? : What Are the Problems? “Malware” Virus- malicious program that piggy-backs on normal existing software to carry out harmful activity. Replicates itself A worm is a variation of a virus that requires no additional software. Replicates itself Trojan horses are programs masquerading as something else. A related variation is “spyware.” Usually do not replicate Invasive intruders

What Viruses and Worms Do : What Viruses and Worms Do May delete or modify files or do other destructive acts Search for e-mail addresses anywhere on your computer and Mail out messages under your name Mail out messages under someone else’s name Mail out nonsense addresses Messages all contain virus attachment May do this at random times with random messages

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What Trojan Horses Do : What Trojan Horses Do Surreptitiously use your computer for purposes such as relaying activity from another computer out to the Internet May also harm your computer May steal private information

How Do We Get Them? : How Do We Get Them? Viruses and worms are typically spread by e-mail attachments Can also come from installing infected programs or from IM programs Trojans often come from installing apparently useful software but can also come from e-mail attachments Another way is from being “hacked”

What Causes Problems? : What Causes Problems? Not using updated anti-virus program Unsafe configurations Failure to put security settings in OE and IE Failure to download security patches Carelessness Don’t click that file! Leaving computer open to hackers

Unwanted Visitors : Unwanted Visitors Unwary or careless computer users can leave their system open to any one on the Internet who wants to come in The Internet is a two-way highway Any computer connected to the Internet is assigned a unique address called an “IP”

When You Click on a Link : When You Click on a Link Your browser broadcasts Your IP address Your browser type Location of the last site you visited Other information

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Ports to the Internet : Ports to the Internet Your computer has many doorways, called “ports”, for receiving information from the Internet Poorly configured computers may leave some of these open to unauthorized visitors Hackers use computer programs to look for these open doors by probing thousands of IP addresses

Many Ports Can Be Open : Many Ports Can Be Open FTP -21 Telnet -23 SMTP -25 Finger -79 HTTP -80 POP3 -110 IDENT -113 Net BIOS -139 IMAP -143 HTTPS -443 and 64,000+ more

Defenses : Defenses Anti-virus programs Firewalls Trojan horse removers System updates System configuration Common sense

Anti-virus Programs : Anti-virus Programs Defend against known viruses and worms Must keep virus definitions updated Norton, McAfee, etc. check e-mail as well as files on computer Can check single files if desired E.g., Norton puts entry in right-click menu Do a full scan regularly

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Some Anti-virus Vendors : Some Anti-virus Vendors Norton (part of Symantec) McAfee InoculateIt (Computer Associates) AVG (free version) from Grisoft PC World reviews at http://tinyurl.com/plvo

Guard the Gates : Guard the Gates Add a firewall Symantec or McAfee suites ZoneAlarm- freeware Sygate- freeware www.pcworld.com/downloads/file_description/0,fid,7228,00.asp Use a router with networks

What Firewalls Do : What Firewalls Do Monitor incoming traffic and block ports from unauthorized probes Monitor outgoing traffic and block any software not authorized to contact Internet Note: Windows XP has built-in firewall but only works for incoming AOL 9 is said to have firewall

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Trojan and Spyware Removers : Trojan and Spyware Removers Anti-virus programs may not catch all Trojan horses Specialized software is available that also removes spyware and adware Ad-Aware (freeware) www.lavasoft.de/software/adaware/ Spybot Search and Destroy (freeware) www.safer-networking.org/

Update with Security Patches : Update with Security Patches Microsoft issues frequent updates dealing with security problems Use Windows Update function to download and install In Windows XP updates can be automatic unless set otherwise If you have Windows 98, launch Windows Update by going to Start--> Settings --> Windows Update

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Use Common Sense : Use Common Sense Never open an e-mail attachment without careful investigation, no matter what the source Do a virus scan on attachment Never, never double-click or open certain types of files unless absolutely sure If in doubt ask sender to verify file If computer behaves differently, check it out

Computer Configuration : Computer Configuration Set up Windows to show file extensions Change security settings in Internet Explorer (applies to AOL also) Configure Outlook, Outlook Express, or other e-mail client Configure network settings

Browser Security Settings : Browser Security Settings For Internet Explorer go to My Computer-Control Panel or Start-Settings-Control Panel Click on “Internet Options” Click “Security” tab Note: these apply to AOL as well

Detailed Configuration Steps : Detailed Configuration Steps http://tinyurl.com/plx2 for configuring IE http://grc.com/ for configuring many things, especially networking

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Some Settings : Some Settings Download unsigned ActiveX controls: Disable Initialize and script ActiveX controls not marked as safe: Disable Run ActiveX controls and plug-ins: Enable Script ActiveX controls marked safe for scripting: Enable Allow cookies that are stored on your computer: Disable Allow per-session cookies (not stored): Disable Java permissions: High safety Drag and drop or copy and paste files: Prompt Launching programs and files in an IFRAME: Disable Navigate sub-frames across different domains: Disable Software channel permissions: High safety Userdata persistence: Disable Active scripting: Disable Allow paste operations via script: Disable Scripting of Java applets: Disable Download signed ActiveX controls: Disable

Configure Outlook Express : Configure Outlook Express Click on “Tools” in menu bar Click “Options” Click the “Security” tab Place Outlook Express in the Restricted Zone Click “Read” tab Uncheck “..Preview Pane”

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More OE Configuration : More OE Configuration Click “View” in menu bar Click “Layout”

OE Configuration (continued) : OE Configuration (continued) Uncheck “Show preview pane”

AOL Users : AOL Users Because of primitive e-mail program prior to version 9, unable to check out messages before opening After downloading an attachment, scan file with anti-virus NEVER double-click unless sure of what file is

E-Mail Attachments to Avoid : E-Mail Attachments to Avoid .EXE .BAT .PIF .SCR .VBS .VBE .JS .JSE .WSH .WSF .REG .SHS And others

Some “Safe” Attachments : Some “Safe” Attachments .JPG .GIF .RM .AVI .MPG .WAV .TXT .DOC .WDB .RTF .HTM .PPT .XLS But safety is relative. Files may have macros or code

More Defenses : More Defenses Use program like MailWasher Can check mail even before you download it Free download at www.mailwasher.net Pro version at www.firetrust.com/home/

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Summary : Summary Use anti-virus program and update the virus definitions frequently Use a firewall when using the Internet If appropriate, use Trojan removing software Keep up with Microsoft security patches Configure computer for safety And very importantly

Don’t Be Part of the Problem! : Don’t Be Part of the Problem! Break the e-mail chain Don’t click on an attachment unless you are sure what it is Remember that e-mail return addresses can be faked Be wary- even your friends may send you a virus

More Information : More Information This presentation available at www.vlaur.com Go to page on “Internet Hazards” Also other slide shows and a number of articles