Virus, Worm and Trojan Horse Infections.
- Do you need Anti Virus Protection?
- Are free Anti Virus products any good?
- What is a Virus?
- What is a Worm?
- What is a Trojan Horse Program?
- What is a Hoax Virus?
- Anti Virus Precautions
- Tips
- Links
Do you need Anti Virus Protection?
Down loaded software from the internet and email attachments are the main sources of virus infections. However any form of transferred media like floppy disks, CD's, DVD's, Zip cartridges, USB data sticks can infect your machine.Pirated copies of the operating system have also been known to have virus's built into them.
If you use the internet or share software or data you are at risk and you do need anti virus software.
The damage that a virus can do is simply not worth the risk. When they are loaded on a PC they can -
- Use your internet connection to sent denial of service attacks on others computers.
- Use your internet connection to sent out spam emails.
- Grant external access to your data.
- Corrupt your data and/or software.
- Make your PC slow, stop or reboot.
You are more at risk if -
- Your PC or Server is left permanently turned on or left unattended for long periods.
- You have broadband (high capacity bandwidth) internet access.
Are free Anti Virus products any good?
Most of the free products are versions of a pay product, they lack certain features found in the paid for product.Typically the paid versions offer improved automation features, they may also be easier to use and offer phone support too.
The Anti Virus protection is usually as good as a paid product, although because its free the update processes can be tedious. This is because the update server(s) may get overloaded at times because of the sheer volume of users.
What is a Virus?
A Virus is any type of self replicating software that infects a computer. The term Virus is however also often used as a generic term for all viruses, worms and Trojan horse programs.Common form: an email file attachment.
- Boot Virus - infects the boot (start-up) sectors on writable disks.
- Executable Virus - infects programs, overwriting existing files or appending the virus to the end of an existing program file.
- Macro Virus - are application specific viruses. Microsoft's Word is a common target with the virus program written in Visual Basic. Using the infected document spreads the virus.
What is a Worm?
Worms replicate across networks usually by email they do not need to infect files on the system. They can cause networks to slow down or crash by mass traffic.Trojan Horse Programs
Trojan Horse programs are commonly disguised as some desirable product or information to entice you to select them. Trojan Horse programs differ from other viruses in that they do not replicate.They usually grant access to your system once in the system the intruder can potentially do anything the local user can do. Disk activity when nothing is running can indicate a Trojan.
Research any software before you load it on your machine. Ideally the software should come from a trusted source and use a search engine to check for any dodgy references to the software.
Usual forms: an email attachment or software downloaded from the internet.
What is a Hoax Virus?
A hoax virus commonly comes in the form of a email warning of some potential virus threat. A hoax email can cause just as much network slow down as a worm. Try to avoid sending the email onto anyone else!!!Anti Virus Precautions
Prevention is far better than cure of course. Here are some simple steps to reduce the risks of getting one in the first place.- Run anti virus software, set it up to make regular scans.
- Keep the Anti Virus software up to date use the internet update option at least once every week or better set up an automatic update.
- Avoid down loading files from an unknown or untrusted source, especially program files. This includes files in email attachments (marked with a paper clip symbol in outlook).
- Avoid opening attachments even from a known source if you are not expecting them. Ask the sender to confirm if in doubt also don't forward them to anyone else.
- Scan any down loaded software using an anti virus package before running it. If you download software onto the desktop for example, with Grisoft's AVG anti virus you can right hand click on it and select 'Scan with AVG' from the menu displayed.
- Turn off the preview pane in your email viewer.
- If you use Outlook Express check that the security options are selected see
Tools»» Options»» Security.- Tick the 'do not save or open attachments that could potentially be a virus' box &
- Tick the 'Warn me if other applications send e-mail as me' box
- Use a software firewall to restrict software access to and from your PC. Note this may not be possible on networked PC's.
- Consider buying a router (hardware firewall).
- If you use Microsoft Windows down load the latest security patches.
Microsoft Operating System users on stand alone PC's or Peer to Peer networks can use the
Windows Update Site
to download any critical patches.
Networked users with a site administrator should leave patching to the administrator!
Tip Don't forget to do backups, however good your Anti Virus strategy is you are likely to get caught out occasionally. If its to time consuming (or expensive) to do a full backup consider a minimal approach and just save the essentials!
TIP Use email filters to split mail from known sources into separate folders.
If you use Outlook Express check that the security options are selected see:
Tools»» Message Rules»» Mail.
Be more cautious with the email from unknown sources its likely to be either spam or contain a virus and perhaps both!
External Links
Peter Frost
Last revised 19th January 2008
This page gets regular visitors looking for horse worming advice. Surrey Councils Worming advice seems a unbiased source for this.