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Security on the Internet

Viruses

Let's start with viruses. In May of 2000, the so-called 'Love Bug' infected tens of millions of computers world-wide, including 80% of federal agencies in the USA, the Whitehouse, Microsoft HQ in Redmond, Washington and many multinational corporations such as Ford, Siemens, and Silicon Graphics.

In the days of stand-alone PCs, before the Internet, viruses were generally transmitted from computer to computer by sharing infected diskettes. Now e-mail is the single biggest threat to the health of your PC.

E-mail messages are essentially text-only and cannot transmit a virus on their own. However, many e-mail programs such as Outlook Express use HTML - the standard language of the World Wide Web - to format documents, enabling malicious programmers to embed hidden viruses in e-mail documents. Wscript/kak.worm, doing the rounds at the moment, is transmitted in this way embedding an ActiveX control which copies the virus into all outgoing e-mails as well making changes to the Windows Registry.

Most e-mail programs allow you to add an attachment in which a virus may be lurking. So what type of attachments can contain a virus? Executable programs (.EXE and .COM files), Word (.DOC) and Excel (.XLS) macros, and zip (.ZIP) files containing any of the above.

Word and Excel documents are particularly vulnerable to viruses. The Prelissa virus (a variant of Melissa) is transmitted via Microsoft Word documents, copying itself into the Normal.dot template used by all Word documents and then into any Word document that subsequently uses this file. Prelissa is programmed to reformat the hard disks of Windows 9x computers on 25^th December, if switched on.

So what can you do to protect your computer from virus attack or, in the event of catching a virus, remove it from your system?

• The answer to this is simple. You must install anti-virus software on your computer and you must keep the software and data files used by this program up-to-date. Norton AntiVirus and McAfee VirusScan both enable you to update your data files on-line, giving you the best protection for your computer. This doesn't mean that you can stop backing up your important data files to disk or tape but does give you piece of mind when using the net.
  
  
• You should scan all your drives for viruses on a regular basis and update your virus files at least once a month.

Anti-virus software is cheap, costing less than $45 for an annual licence. Repairing the damage caused by a virus can run into hundreds if not thousands of dollars.

Security of Your Computers