Keep your PC healthy

7th November 2003 at 00:00
Your computer is under attack. As viruses and worms proliferate, George Cole examines ways to protect your hard drive from harm

When Helen Yewlett returned to her classroom after the summer break and switched on her school's computers, she was in for a shock. Yewlett, who is ICT co-ordinator at Ysgol Gyfun Ystalyfera School in the Swansea valley, found that almost all of the 28 computers in her room were infected with a virus. The school's network of 284 computers had to be shut down and each PC individually checked for infection. The experience of Ysgol Gyfun Ystalyfera shows the devastating effect viruses can have on a school network and Helen says it took many hours of technician time to solve the problem.

A computer virus is a generic term for several types of programs that can infect computers, networks and servers. All of them consist of malicious code that can wreak havoc on a school's ICT infrastructure. The damage caused by viruses can be seemingly trivial (causing a message to appear randomly on your computer screen), obstructive (stopping a computer from running properly or causing it to crash), destructive (deleting dozens of programs or important files) or sinister (secretly recording all your keystrokes or searching for passwords and then sending the information back to a hacker).

There are three main types of programmes which hackers use to attack computers:

* virus - a program that infects other programs, replicating itself as it does so and passing the infection on to other computers.

* worm - a program that works like a virus but doesn't require another program to replicate itself. Many worms hi-jack email address books and then send themselves to other computers. It was one of these, W.32 Wlchia, that affected Helen Yewlett's school, but probably the best known is the SoBigF worm which brought many companies to a standstill earlier this year.

* Trojan horse - a program hidden inside another. For example, a downloaded game or piece of shareware software may also contain a Trojan, which operates silently in the background. Sometimes viruses are combined so that, for example, a worm may also carry a Trojan horse.

Computer viruses can be picked up in a variety of ways, from loading infected floppy disks or CD-Roms to downloading email attachments or programs from the internet - you can even become infected by simply visiting a website. The latter are so-called "drive-by" infections caused by the virus writer exploiting holes in your web browser's security.

The vast majority of viruses are aimed at computers running Microsoft Windows, mainly because there are many more Windows users than people running Apple Macintosh or Linux computers. But there are many things we can do to reduce the risk of catching a computer virus.

If you are running Microsoft software, there are a variety of built-in security features that can be used to make your computer or network safer.

Popular email programs like Outlook can be set to block email attachments often associated with viruses. The Internet Explorer browser has adjustable security and privacy settings that make it harder to attack your computer.

The Windows XP operating system has a built-in "firewall" or filter, which controls the internet traffic entering your computer. Firewalls offer protection against Trojan horses. Note that the Windows XP firewall is normally switched off - you have to turn it on manually. Also, the firewall can affect network systems, although Microsoft is working on this issue.

Microsoft also periodically releases software updates or patches via its Windows Update website, which are designed to plug Windows' security holes.

In addition to this, anti-virus software from companies such as Symantec (Norton) and McAfee is a must. These use scanners to detect viruses and will also quarantine and delete viruses. And even if you use Windows XP, it's a good idea to use a separate firewall for added security.

Companies such as RM and Time Education publish regular virus alerts and information on their websites, and can also provide fixes for their customers.

The final barrier is behaviour. Discourage students from running their own software on the school network and be wary about opening attachments, even from people you know (see sidebar). Other potential sources of viruses are music file-sharing networks like Kazaa (you might also mention to your students that music companies are now suing individuals who use this site).

Viruses are unlikely to ever go away completely, but life will get tougher for the virus writers, says Scott Charney, Microsoft's chief "trustworthy computing" strategist: "No security will ever be absolute, but in the future, security will be built into your PC's hardware and programs will only ever run if they are from people you trust through the use of digital signatures. But protection will always be a combination of technology and the way people use their computers."


* Virus Hoaxes are false warnings about viruses that spread through the internet like wildfire, tricking people into deleting legitimate files.

Never pass them on. avcenterhoax.html

* Scumware is the name for parasites that can hi-jack your browser or even tracking your movements online (spyware). A good program for dealing with scumware is Lavasoft's Ad-Aware.

* Spam is unsolicited email or junk email. Filtering software can be used to remove a lot of spam, but no system is perfect




* Use the built-in security features found on Windows, Outlook and Internet Explorer

* Download and install security patches from the Windows Updates website

* Use anti-virus software

* Use a firewall

* Be wary of any attachments

* Watch out for attachments with file suffixes such as .exe, .scr, .bat, .pif, and .vbs. Also watch out for double suffixes like.jpg.exe

* Contact your ICT supplier for up-to-date virus information

* Educate staff and students on how to reduce risk

* Back up all important files

* Have a system for dealing with virus infection in place

RM is planning another series of UK one-day conferences for school decision-makers for March next year. The popular events with high-profile keynote speakers, which this year attracted more than 1,000 school leaders, will be split into primary and secondary next year.

Primary: 08709 086969

Secondary: 08709 086868


* Apple has cut the price of its education computers. The desktop eMac, with 17-inch screen, iLife software and Superdrive capable of showing and burning DVDs and CDs starts at pound;649 (inc VAT). The G4 iBook range is cheaper too, with the 12-inch screen version, with iLife and Combodrive capable of showing DVDs and writing CDs, starting at pound;849 (inc VAT).

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