Junk Email and Viruses

What is Junk Email?

Most households will be familiar with promotional material for everything from the current bargains at the local supermarket to what's on the local theatre, delivered to you through your letterbox.
The electronic version, commonly known as spam, promotes everything from… well just about everything!
For a few dollars, a spammer can purchase a CD containing millions of email addresses, then send millions of spam emails to addresses all over the world. The addresses are usually "harvested" from web pages posted in the Internet, but some are supplied by Internet Service Providers and companies who ask you "logon" in order to view restricted pages.

What is a Virus?

A virus is malicious code, designed to corrupt data on your computer, and any other computers it can find. The code can do anything from playing endless Barry Manilow songs, to totally wiping all the data on your computer.
Typically, viruses are subtler in delivering their payload. Many recent viruses, such as "SirCam", take advantage of loopholes in the computer's operating system or programs. For example, a virus might replicate itself, attach itself to a document found in a common storage area, and send itself to every email address found in the address book of the computer's email program. That could mean sending you profit and loss spreadsheet file to all your friends and business associates!

Junk mail, Viruses and speed

Junk mail and viruses can affect your speed in a number of ways.

Downloading data that you didn't ask for is a waste of bandwidth. If you want to download a 4MBytes MP3 file while your email program is busy downloading 2MBytes of junk, your download time is going to be longer.
Some viruses read email addresses from your email program's address book, then send files (infected by the virus) from your computer to all those addresses. Thy often have their own mail engine, so you want have any record of the files being sent. The "SirCam" virus, for example, send a 360KBytes version of a file in the "My Documents" folder to addresses picked from cached web pages. Cable and DSL modem users, in particular, may be un-aware that their computer is constantly sending out vast amounts of private data.

Avoiding Junk Mail and Viruses

Although it is probably impossible to avoid being hit by a virus, here are some tips to reducing the risk of infection:

Use anti-virus software, and update it regularly. New viruses appear every day, and can propagate around the world in hours.
Avoid downloading junk email and viruses by screening your email before you download it. Check out my own multi-platform Java application here.
Don't store important information in predictable locations. For example, MS Windows users shouldn't store documents in C:\My Documents, or Email Addresses in the Outlook or Outlook Express Address Book. Indeed, you shouldn't install Anti-Virus software in the folder suggested by the installation program as some virus simply delete known anti-virus folders. If you really want to use the Outlook / Outlook Express Address Book, include an entry that will never be delivered (aaaaa@aaaaaa.aaaaaa) and your own email address. This way, if a virus does manage to send a message to every address in your address book, you'll get a message from yourself and a warning that an email could not be delivered!
If your email address is published anywhere on the Internet, expect it to attract junk mail. Remember that addresses posted to Newsgroups could also be harvested. Set-up a separate private account for use by your family, friends and business associates, allowing you to change your public address at will.
Don't open attachments unless you are sure who they are from and what they contain. Junk email and virus writers try to trick you into becoming exposed to their advertising or malicious code.
Many junk emails encourage you to click a link at the bottom of the page in order to be removed from their mailing lists. Often, you are simply letting them know that your email address is valid, and therefore should not be removed. Also, it may earn them another few cents from their sponsors. Valid removal links, should be easily recognisable, and relate to a valid web page. Beware of links to IP numbers. For example, http://123.45.67.89 could be anywhere. It would be relatively easy to copy the homepage and other pages of the Amaxon.com website, and ask surfers to go to http://123.45.56.67.78/books/ordering.htm with their credit card details! And recent viruses entice you go to a web page, where a script on the web page delivers a viral payload.
When sending and replying to email, send documents as Rich Text Format or better still plain text, as opposed to Word documents, which can carry macro viruses.