Avoiding Computer Viruses

Computer viruses add instructions to other programs or storage devices and may attack, scramble, or even completely erase computer data. The big danger however lies in their ability to replicate themselves and spread from computer to computer. Few computers, even those with good security, are immune to infection.

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High-risk behaviour

So what are the most common ways of getting computer viruses and how can you reduce your chances of getting one?

  • Sharing computer programs and disks, or downloading files and software through file-sharing applications such as KaZaA, BitTorrent and similar is a sure way to find your machine riddled with viruses, trojans and worms.
  • Clicking links in instant messaging (IM) that have no context or have only general text
  • Downloading executable software from public-access bulletin boards or web sites
  • Using removable disks such as floppies or USB devices on computers used by more than one person
  • Opening email attachments from people you don't know or without first scanning them for viruses
  • Opening email attachments from people you DO know, possibly more dangerous than the item above. Just because it's a friend or family member doesn't mean they have an uninfected machine and they can easily send you a virus without ever being aware of it themselves. ALWAYS virus check email attachments if your virus checker doesn't do it for you automatically.
  • Opening any email attachment on a computer running Microsoft Windows. Text (.txt) attachments are probably safe. Treat anything else with caution. Even Word and Excel documents may contain viruses (in particular, you should ensure that all Office applications are configured to warn you before opening a document containing macros. You should never enable macros when opening an Office document sent as an attachment)
  • Continually running your Windows computer as an administrator

Signs of infection

If your computer begins to act strangely, or if it stops being able to do things it has always done in the past, it may be infected with a virus. Symptoms such as slow program load times, unpredictable program behaviour, inexplicable changes in file sizes, inability to boot, strange graphics appearing on your screen, or unusual sounds may indicate a virus is on your system. Unfortunately, these symptoms can also be caused by corrupted system files. If in doubt, run a virus scan and a Trojan scan if your virus checker does not do both.

Avoiding computer viruses

Recommendations for safe computing:

  • The most important thing you can do to keep your computer safe is to install virus detection software and keep the virus signatures up to date. Antivirus programs perform two general functions: scanning for and removing viruses in files on disks, and monitoring the operation of your computer for virus-like activity (either known actions of specific viruses or general suspicious activity). Most antivirus packages contain routines that can perform each kind of task.
  • If you have a broadband connection make sure you have a Firewall. Windows XP has its own and it must be turned on. Some Anti-Virus packages come with a Firewall and you can also download standalone software to do this. In either of these cases you should turn the Windows Firewall off to avoid conflict problems.
  • Keep your operating system current with the latest patches and updates. The writers of viruses, trojans and worms often exploit bugs and security holes in operating systems and other computer software. Software manufacturers frequently release patches for such holes. Always make sure your software is set to look for automatic updates whenever possible.
  • Back up your files. Sometimes the only way you'll get rid of the virus is by deleting the file completely, especially if it's a new virus that doesn't yet have an disinfector. Note: If you back up a file that is already infected with a virus, you can re-infect your system by restoring files from the backup copies. Check your backup files with virus scanning software before using them.
  • If you must insert one of your application disks into an unknown computer, make sure it's write-protected, and unlock your application disk only after verifying that the machine is virus-free.
  • Obtain software from reputable sources. Check newly downloaded software thoroughly using reputable virus detection software. This can also help protect you from Trojan horse programs.
  • Quarantine infected systems. If you discover that a system is infected with a virus, immediately isolate it from other systems. In other words, disconnect it from any network it is on and don't allow anyone to move files from it to another system. Once the system has been disinfected, you can copy or move files.
  • If you use Outlook or Outlook Express, try not to use the preview pane feature. Although you haven't physically opened the email, the fact you can see part of it means the program has opened it.

Links to prevention software

Provided below are links to some software that will help you keep your computer free of Viruses, Trojans and Worms. This is not a one off attack though, you must keep these up to date with the latest signatures or they become as good as useless. Many provide an automatic update feature that you should turn on. Some will require you to subscribe in order to have this feature, though none are expensive, especially when compared to the hassle if your machine suddenly crashes and burns or starts infecting your clients.

We can personally recommend all of these as we run them ourselves. The only proviso is that you must read the instructions after you have installed as some require additional settings or immunisations. JBVisions clients are free to call us for assistance or further information.

  • Bit Defender Anti-Virus. This is recommended by many large IT suppliers and we have been using it ourselves for a number of years during which time, the only virus we have had on our machines was one where we didn't follow our own recommendations above. It also contains a firewall.
  • Spyware Guard. Running happily alongside Bit Defender, this blocks Spyware and protects against Browser Hijackers. Recommended if you're using Internet Explorer.
  • Spyware Blaster. A twin application to Spyware Guard, this can help keep your system spyware-free and secure, without interfering with the "good side" of the web.
  • Spybot Search & Destroy. Another spyware checker that runs along with the others. We are of the opinion that running several compatible checkers together ensures that problems don't get missed. Despite their best efforts, security companies do miss the odd one or two.
  • XoftSpy. And another spyware checker that happily runs alongside all of the above..