Secure Your Home Computer

{LANG_NAVORIGIN} Enterprise Security Home Office
By: TomCat Internet Solutions, 03/06/2005

Internet privacy protection

• Use a web content filter (or browser filter) to prevent remote site contact through ad banners and embedded web bugs. They are built into most browsers, but third-party programs usually offer better filtering and configuration options.
• Enable the popup blocker in your web browser. The better browsers have this built in.
• Disable HTML for e-mail or choose to view all messages as plain text if your e-mail client has such options - the better ones do; or use an e-mail content filter for web bugs and embedded content originating from a server other than the one belonging to the sender of the e-mail.
• Disable cookies in e-mail if your e-mail client has such an option - the better ones do.
• Encrypt your stored passwords. Most browsers include an option to store your online passwords. Be sure yours are stored encrypted and you set a master password for access.
• Set your browser for maximum privacy, forcing it to prompt you for permission for everything possible from cookies to downloads as well as security permissions for Java Classes (Mozilla, Firefox, Opera, and Netscape) and ActiveX Controls (Internet Explorer) as mentioned above. Once you become familiar with a site you can always add it to an 'approved' or 'trusted' sites list in your content filter or browser to avoid the annoyance of continuous prompts, but apply some caution as this is for absolutely trusted sites only.
• Clear your browser cache (called "Temporary Internet Files" in IE) and browser history often, and always after visiting any site where you performed personal business - online banking, making a purchase, etc.
• Don't tell sites anything you don't want them to know. Use common sense when filling out forms or submitting any personal information unless you are absolutely sure it won't be misused.
• Read a site's privacy policy. The presence of a privacy policy does not mean that a company won't collect or sell your information. Read it carefully. If it is vague or unclear, watch out. If you can't find one, get out!
• Don't install spyware, and use adware cautiously. Many freeware, shareware, and adware programs not only contain spyware, but can contain viruses or worse - trojans! Make your selections carefully and always do a Google search on software titles for all the information you can gather.
• Opt out of everything from mailing lists to requests to use your personal information for whatever purpose is intended, and beware of sites that offer some sort of reward or prize in exchange for your contact or other information.
• Never respond to spam by using their "click here to unsubscribe" or "follow this link for removal from our list". The one and only thing this does is verify that the spam was delivered to a valid e-mail address and confirm that you saw it. The sender has no intention what so ever in honoring your request. In fact, by responding you are guaranteed the delivery of even more spam from the same sender plus those who were sold your confirmed-valid address. Destroy the spam without responding to anything.
• Never give your personal e-mail address to a commercial vendor. This applies to anything from making a purchase online to responding to an online survey. Apply for a free Webmail account or subscribe to a Disposable E-mail Service and use that address instead. You can always dispose of it and acquire a new one quite easily if necessary.
• Never use your personal e-mail address when posting to message boards or newsgroups. Always use a webmail address if a valid address must be supplied. Spiders are constantly crawling these places for addresses to use for spam. If you must use your personal address, or any valid address you plan to keep, always insert some text that the viewer will know to remove when responding to you. No one will question your intent - this is standard practice.
• Never reveal personal details to strangers. Period.
• Realize you may be monitored at work. Avoid sending highly personal e-mail to anyone including mailing lists, and keep sensitive files on your home computer.
• Use anonymizers cautiously. They are not as private and secure as you might think. It is far better to avoid the sites where an anonymizer might be needed.
• Keep informed. Visit privacy sites frequently. Read the news. Apply what you learn.

Cookies

Companies try to personalize web site experiences for their visitors. Some remember your login name and password for your convenience upon subsequent visits. Others offer news, stock quotes, and weather tailored to people's interests and location. This is done with a cookie, a small file created by the site, that collects specific information about your preferences or web browsing activities and stores it on your PC. Allowing all cookies, however, is unacceptable for those who care about privacy.

Although cookies are often used in such ways that are beneficial to you as you move across the Internet, many more are not. Such cookies are used with the sole purpose of gathering information and are beneficial only to those who place them on your computer. Tracking networks such as DoubleClick and MSN LinkExchange use cookies to monitor which site you were on when you clicked a particular banner ad and what you did once you got to the advertiser's site. They can put cookies on your PC and then read them across many sites - tracking your surfing habits and building a profile about your preferences.

Though this can be alarming, you are not left without the option to take control of the cookies that are used to invade your privacy. You can completely close this privacy gap as long as you apply basic cookie management techniques. Cookie filters will allow you to accept or deny each cookie upon arrival. They will also allow you to set automatic handling rules for future cookies - always accept those from sites you trust and visit frequently or always deny those from sites that have no business knowing your own. Cookie filters can also be instructed to always deny "third-party" cookies - those that do not directly originate from the site you are currently visiting. Third-party cookies are most often used by advertisers and marketers.

Spam

Take advantage of the built-in junk mail filters inside your e-mail client. In addition, configure your own filters to automatically trash or delete incoming e-mail that contains certain keywords. By using a combination of various filters you can noticeably reduce the amount of spam reaching your inbox.

Dealing with Spam
Automated reporting systems used to be the preferred choice when dealing with spam but for all practical purposes are simply just a waste of time. A more effective way of dealing with this nuisance is by setting up your own e-mail filters to weed out and destroy the junk. Mozilla and Mozilla Thunderbird have excellent built-in junk mail filters that with a little training are quite effective. Still, you might want to manually set a few rules.

You can set up as many filters as you like in your e-mail client. It is always wise, though, not to automatically delete the filtered mail until you are certain the filter is properly configured. You can always change it later.

Our example below shows you how to filter for spam arriving from a certain country, but you can set your filters to test for just about any string of text found in the e-mail header and/or message body. We are routing mail from that country into a specific folder, keeping it out of our inbox, but saving it somewhere else to be manually deleted later. Once we are certain the filter is working properly, the action performed can later be changed to "delete".

For e-mail that is malicious or threatening, contact your ISP immediately! Many ISPs destroy their server log files after 48 hours and that evidence is critical. Your ISP should be able to advise you how to proceed with filing your complaint. Also, be sure to include all headers that are embedded in the e-mail, as every piece of information is needed to trace its origin.

Configuring Spam filters in Mozilla Mail and Mozilla Thunderbird

1. Click Tools >> Message Filters
2. In the Message Filters window click "New"
3. In "Filter Name:" enter "Slovenia Spam Filter" (or any name you like without the quotes)
4. Under “For incoming messages that:” select “Match any of the following”
5. In the first drop down box select "Sender"
6. In the second drop down box select "Contains"
7. In the textbox, enter “.si” (without the quotes)
8. Under “Perform these actions:” select “Move to folder”
9. Click the “New folder...” button
10. In the New Folder window under "Name:" type "Slovenia" (or any name you like without the quotes)
11. Under "Create as a subfolder of:" select "Local Folders", "Inbox", "choose this for the parent"
12. Click OK to close the New Folder window
13. Click OK to close the Filter Rules window
14. Be sure a check mark appears next to your new filter under "Enabled"
15. Just click on the "x" at upper right to Message Filters window

Configuring Spam filters in Netscape Messenger

1. Click Edit >> Message Filters
2. In the Message Filters window, click "New"
3. In "Filter Name:" enter "Slovenia Spam Filter" (or any name you like without the quotes)
4. Under “For incoming messages that:” select “Match any of the following”
5. In the first drop down box select "Sender"
6. In the second drop down box select "Contains"
7. In the textbox, enter “.si” (without the quotes)
8. Under “Perform these actions:” select “Move to folder”
9. Click the “New folder...” button
10. In the New Folder window under "Name:" type "Slovenia" (or any name you like without the quotes)
11. Press the “Click here to select” button
12. Specify a choice and click OK
13. Click OK to close the Filter Rules window
14. Be sure a check mark appears next to your new filter under "Enabled"
15. Click OK to close the Message Filters window

Configuring Spam filters in Microsoft Outlook

1. Click Tools >> Rules Wizard >> New
2. Select “Start creating a rule from a template”
3. Select “Move new messages from someone”
4. Click Next
5. Under “Which condition(s) do you want to check?” click the box next to “with specific words in the sender’s address” (Clear any other boxes that are checked.)
6. In the “Rule description” box, click “specified”
7. Select the Slovenia folder, or click New to create the Slovenia folder
8. In the “Rule description” box, click “specific words”
9. The Search Text box will open. Type “.si” (without the quotes) in the “Specify a word or phrase...” box
10. Click Add >> OK
11. Click Next
12. In the “What do you want to do...” field, select “move it to the specified folder”
13. Click Next >> Next
14. In “Please specify a name for this rule,” enter Slovenia Spam Filter
15. Select “Turn on this rule”
16. Click Finish
17. Click OK

Configuring Spam filters in Eudora

1. Click Tools >> Filters
2. Under Match, check Incoming
3. Under Header, choose From:
4. In the drop down box below Header, select Contains
5. In the textbox to the right, enter “.si” (without the quotes)
6. In the Action area, in the first drop down box, select Transfer To
7. Click the long command button to the right (it says “In”)
8. Select the box to which you want to send Slovenian e-mails (If you don’t yet have a box, select New and create one.)
9. Click File and Save

Test for Security Vulnerabilities

Use an online service to test the security of your computer's connection to the Internet. Be sure to include a check for identity vulnerabilities and port scanning.

Examine the results and make adjustments to your firewall and/or network settings and apply software patches wherever required for maximum defense. Closed ports are good - stealthed ports are better - but keep in mind that more often than not, security problems exist with the software and not with the ports through which they are granted access.

Use Common Sense

Examine your firewall and router logs frequently for suspicious incoming or outgoing traffic. If you suspect you are a victim of a hack attack, that someone did in fact compromise your system, go to www.fbi.gov for instructions on gathering proof and filing a report. Also look for changes on you hard drive such as unknown or changed files and folders and decreased hard drive space. Do not delete but rather quarantine anything suspicious mainly because you will need this information for evidence, but also because a file that looks suspicious is not always bad - it might be critical system or program file that you need to restore.

Keep current backups of all personal and system files. A backup can restore lost data in the event your system's security is compromised or your critical files become corrupt. Keep copies of everything you would need for both a simple restore (the replacement of just one or two damaged files) and a major restore (bringing your system back to its original state). And in the event of something very serious - like a hard drive crash or trojan damage - you should always be prepared to re-install your OS from scratch. This means not only keeping your installation CD for Windows in a safe place, but also the installation CDs for all of the other programs you have installed plus any personal files (address books, e-mail, documents, etc.) that will certainly be destroyed when you re-format a hard drive partition. If you backup your files to another hard drive partition for easy access, ideally you should also place copies onto external media such as a CD, Zip disk, or removable hard drive.

What system files to backup? Daily backups of your registry files are recommended and you should keep at least 7 of the most recent copies. In addition, always create a backup before installing any new program or making any changes to your system settings.

For Windows 98 users - keep backup copies of WindowsSystem.dat and WindowsUser.dat. If you are using User Profiles, you will also find a copy of User.dat under each WindowsProfilesprofilename. Simply copy these files to another location for safe keeping. If you need to restore these files, just boot to a command prompt and copy the files back to their original locations.

Since system files in Windows XP cannot be simply copied while they are in use, XP users should use System Restore to create restore points. (A shortcut is placed by default under System Tools in the Start Menu, or you can find it at %SystemRoot%System32restorerstrui.exe.) In addition, we recommend a wonderful freeware utility called ERUNT (The Emergency Recovery Utility NT). ERUNT is a Registry Backup and Restore for Windows NT/2000/XP and will copy your critical system files in their original form to any location you specify. ERUNT will create a backup set which includes a utility for restoring the files to their original locations. To restore the registry from outside Windows, just copy the files back to their original locations.

If you are selling your computer, thoroughly clean your hard drive. Deleting files and reformatting is not enough. Reformatting does not overwrite every sector, and private information can remain retrievable. Use a secure delete or disk wiping utility to overwrite every sector on all hard drives. Be sure to use a utility that supports the U.S. DoD standard of seven passes or wipes. While this method is good enough for most people, be aware that the only absolute way of destroying all traces of everything your hard drives is to have these disks degaussed (demagnetized) and physically destroyed.

Copyright 2005 TomCat PC Systems














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