Email Viruses

Viruses like the 2003 SoBig attack can wreak havoc on your computer system - at home or at work. To date, more than 60,000 types of viruses have been defined. While there is no foolproof way for you to block all viruses, following are a few tips to help you understand and reduce virus problems.

According to TechWeb, a virus is "Software used to infect a computer. After the virus code is written, it is buried within an existing program. Once that program is executed, the virus code is activated and attaches copies of itself to other programs in the system. Infected programs copy the virus to other programs."

The effect of the virus may be a simple prank that pops up a message on screen out of the blue, or it may destroy programs and data. It can lie dormant and do its damage once a year. For example, the Michaelangelo virus contaminates the machine on Michaelangelo's birthday.

Although not the only kind of computer virus, e-mail viruses are the best known and undoubtedly cause the greatest loss of time and money overall. An e-mail virus is computer code sent to you as an e-mail note attachment which, if activated, will cause some unexpected and usually harmful effect, such as destroying certain files on your hard disk and causing the attachment to be remailed to everyone in your address book.

To help protect yourself:

1. Install and use anti-virus software to scan any attachment before you open it. If you're a home or individual user, check out CNET's reviews of the top antivirus packages. (Currently, CNET's Editors' Choice antivirus software is McAfee VirusScan 7.0.) If you're on a network, check with your network administrator first.
   
2. Obtain the latest upgrades for your operating system, virus-scanning software, Web browser and email applications. Microsoft notes that many of their clients aren't downloading and installing its patches promptly. Visit www.microsoft.com/security/protect for instructions for your Windows machine.
   
   Frequently visit the Web sites of your software vendors and download the latest security patches and "virus definitions" for your virus monitoring software. Configure your virus checker to scan all incoming email attachments and files that you download from the Web or from FTP servers and delete all suspicious files.
3. Add firewall protection - especially if you have a broadband connection like DSL or cable modem. Software firewalls are available to protect personal computers from attack. For a list of software firewalls for Windows, see www.microsoft.com/security/protect/firewall.asp
4. Back up your active files, including important emails, daily. If your system is attacked, you'll have the data you need saved and ready to reinstall. You can even copy your data onto removable media (e.g. floppy disks or CD-ROMs) that you keep in a separate location. As an added precaution, use two or more backup disks in case one of the disks fails.
5. Be cautious about opening email with attachments you're not expecting and/or unusual content. Some viruses forge their return addresses, substituting your friends' (pulled from your email address book) or even your own. Look at email subject lines and content to see if it really sounds like the person you know.
6. Urge friends who distribute jokes, political messages and other messages to place all the addresses in the "blind carbon copy" (BCC) field. If they include all the addresses in the "to" field, the widely distributed messages can unintentionally deliver your email address into the hands of spammers and virus writers.
7. Configure your email application so that:
   

• Your "list" view reveals which incoming messages have attached files before you open them.
• Your full name (and not just your email address) automatically appears in the "from" field in messages you receive and send. Recipients may not immediately recognize you by your email address alone, particularly if you have multiple email accounts.
• It does not automatically activate attachments or run JavaScript or Java applets contained in messages. If you're operating with Windows, configure it to reveal file extensions. (Check your software program's "help" options to determine how to make changes.)
  
  Even friends may unwittingly send a virus that attacks files on your hard drive or compromises the security of your data. Always be suspicious of attachments with certain file extensions and avoid opening (for example, double-clicking on) an e-mail attachment unless you're expecting it from someone and know what the attachment contains:
  

• .bat (batch file, which contains a sequence of commands for a computer operating system);
• .exe (executable file - a program);
• .pif (program information file containing data to execute an applicaiton on a Microsoft Windows system);
• .scr (screensaver or script written in Visual Basic or Java);
• .vbs (script file written in Microsoft Visual Basic);
• .hta (HTML file used by viruses to gain access to a computer's operating system);
• .reg (registration file, which controls aspects of the Windows operating system or applications).
  
  About viruses, worms and Trojan horses : And you thought we were talking about illness, bugs and mythology! Computer viruses are named viruses, worms and Trojan horses because they can replicate themselves, as biological viruses do. Often concealed within games or images distributed on the Internet, viruses can modify other programs and compromise data or your computer's system integrity.

• Computer worms are actual programs that burrow into the active memory segment of a computer, where they may carry out unauthorized functions.
• A Trojan horse is not technically a virus because it does not replicate itself, but it is destructive nevertheless. A Trojan horse appears to be a benign program, but may alter or destroy data.
• Because of its prevalence, Microsoft Windows is often the preferred target of the hackers who produce viruses and worms. The Linux operating system and Apple Macintosh computers are less likely to be attacked.

9/03

Sources: www.techweb.com