Preventive medicine for your computer

Using the Internet can pose serious risks to your computer's security. Here are some things you can do to prevent problems!

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by Jeffrey B. Dalin, DDS, FACD, FAGD, FICD

The Internet can open the doors to huge amounts of new and exciting information. You can shop, have fun, educate yourself, share information, and more. Spam is becoming a greater nuisance every day, but while it is irritating and time-consuming to wade through, it doesn't damage your computer. It can easily be controlled by using your delete key.

However, if you do not initiate safegards, using the Internet can pose serious risks to the security of your computer and your personal information. For example, a virus is a program that makes copies of itself and infects diskettes or computer files. Viruses can spread from one computer to another whenever you exchange files or diskettes with another user. Often, these files come as email attachments, frequently from people you know and trust. These email senders have no idea that they are passing on a file with a virus in it. The damage these viruses can inflict varies. Some can erase or change the information stored on your computer. Others may do little or no harm to your system.

Viruses can carry a damaging payload, such as a worm or a Trojan horse program. When a virus infects your computer, it can make copies of itself, potentially filling up your hard disk space and then sending itself to everyone in your address book. Some viruses can even reformat your hard drive, delete files and programs on your drive, or install hidden programs — such as pirated software — that can then be distributed and sold over your computer without your knowledge.

10 virus detection and prevention tips

Following these simple steps on a daily basis will prevent a lot of problems:

1) Do not open any files attached to an email from an unknown, suspicious, or untrustworthy source. Scan all incoming email and attachments.
2) Do not open any files attached to an email unless you know what it is, even if it appears to come from a close friend or someone you know. Many viruses replicate themselves and spread through email by accessing the infected person's address book. Better to be safe than sorry and confirm with your friend that they really sent you a clean attachment.
3) Do not open any file attachments if the subject line is questionable or unexpected. Sometimes you need to hold off opening an attachment until you have contacted the sender and verified their intentions.
4) Delete chain emails and junk email. Do not forward them or reply to any of them. Often these are strictly spam.
5) Do not download any files from strangers.
6) Exercise extreme caution downloading files online. Ensure that the source is legitimate and reputable. Verify that an anti-virus program checks the files on the download site. If you are uncertain about the file, download it to a floppy and test it with your own anti-virus program.
7) Update your anti-virus software regularly. Hundreds of new viruses are discovered each month, so you will need regular updates to be protected. You also need to update the product's scanning engine. Schedule weekly disk-drive scans. Check the anti-virus icon on your task bar regularly to make sure your software is active and functioning. Also, be sure to update your operating system and email programs. Microsoft often has security updates available on its site to help protect you.
8) Back up your files regularly. If a virus destroys your files, you can replace them with your stored data. Always store your backup copies in a separate location.
9) When in doubt, always err on the side of caution. Do not open, download, or execute any filesor email attachments if you have any questions. You cannot be infected if you follow this practice.
10) If others use your computer, make sure they follow these same rules.

What to look for

How do you know if your computer has been infected with a virus?

1) Your computer slows down. This could indicate unauthorized activity going on in the background.
2) You notice a lot of unusual modem activity. Your computer may be supplying software or data to others without your knowledge.
3) You become aware of unusual computer behavior. If applications are not working properly or if your files seem to be corrupted, there is a good chance you have been infected.
4) Your anti-virus software alerts you to problems. Many programs will alert you if a virus is attached to an email or is in an executable file. Many will even go a step further and immediately delete them from your computer or place them in quarantine, which renders them harmless.
5) Odd text messages appear on your computer..
6) Programs or data files are damaged or deleted.
7) Available RAM decreases unexpectedly. Some viruses load into memory and will use up your available RAM.
8) A large number of unknown files begin to appear on your computer.
9) Your PC starts acting strangely. Applications may freeze, crash, or produce unusual error messages.
10) Your PC won't boot and you cannot access your main drive.

Without a firewall, your computer is operating under an "open door" policy. Any information on your computer, such as account numbers, passwords, credit card numbers, etc., can be shared with the world. This information is available to anyone with bad intentions and some computer skills. Hackers can get into your computer, take what they want, and leave open a "back door" so that they can use your computer again. Every minute your computer is connected to the Internet, it is at risk.

Most people think their anti-virus software protects them from all Internet-borne threats. Anti-virus software will prevent infection of your computer by attached email and document or program viruses, but it does not secure your computer against a direct attack by a hacker.

A firewall is software that monitors all incoming network traffic and allows in only the connections that are known and trusted. Port 80 is open so that you can browse Web pages, port 1863 allows you to engage in instant messaging with friends, and port 443 gives access to secure Web pages used by online merchants to encrypt purchases.

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However, there are 65,535 ports available under Internet protocol. You can manually grant or restrict access to these ports, but this task would eventually become impossible. Each time you added a new program that required Internet access, you would need to reconfigure your computer. Firewalls allow access to the ports you need open and closes off those you don't use. It also makes your computer "invisible" on the Internet. If hackers can't find you, they can't attack.

Make these activities to detect and prevent security violations part of your office routines. Use common sense while online, especially when deciding whether or not to download a file. Be very careful when checking your email. Just because an infected attachment has arrived on your computer doesn't mean your computer has been affected. If you don't open the attachment and delete the email, the infected document does not have a chance to get into your system. If you follow these suggestions, you will feel more secure when you hear about Blaster Worms, Sobig, I Love You, etc. You will know you have done your best to prevent your computer from becoming infected or damaged.


Major types of computer viruses

1) Macro virus: These viruses are spread by sharing document files created from programs such as Microsoft Word or Excel. They can infect files created on a Windows or Macintosh computer. Once infected, any Word or Excel document you create may contain the virus.
2) Boot sector virus: These viruses are spread by sharing diskettes. Any diskette can spread a boot sector virus, even if it is not a bootable system diskette. If you share files on diskettes, be sure to check them for viruses.
3) Program virus: These viruses are spread by sharing program files. This virus does not occur often because people usually only share data or document files, not programs.
4) Email virus: These are not usually virus programs. These are usually emails sent by well-meaning people to warn others about a new virus. They usually cause huge amounts of Internet traffic, and then turn out to be hoaxes. Check with knowledgeable people before forwarding any messages warning you about new viruses.

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