There's 100,000 of them . . and they're after you

Trojans, worms and viruses are on the warpath across the globe and pose a growing threat to millions of home computers As a new study reveals that the number of malicious computer programs has reached the 100,000 mark for the first time, Adrian Mather looks at the dangers facing us in our own homes and what we can do to ward off an attack

YOUR secret password is designed to protect you and your personal data. You may use your PC to store details of your finances or your accounts. You may have used your credit card via an internet site to book a hotel room, or pay for your weekly groceries.

Private e-mails you have sent to friends, family or business contacts could be being read by strangers.

Your computer and its programs are designed to hide such information from prying eyes. But do they?

New figures announced by computer security firm McAfee have shown that the number of malicious programs that can attack personal computers has now passed the 100,000 mark for the first time.

Bank details, important passwords and corporate information stored on computer hard drives are now at constant risk from a stream of programs known as viruses, worms and Trojans that can infiltrate PCs via the internet and wreak havoc in offices and homes across the globe.

By gaining details of your bank, sort code, account numbers or credit cards, snoopers can use this information to make purchases of their own via the net.

Your computer may already be one of thousands a day that have been secretly hijacked to spread viruses to other users and systems via your own personal e-mail address.

It is even conceivable that such access would allow intruders to send e-mails to others purporting to come from you.

McAfee says it has seen big increases in the number of viruses produced as creators of malicious programs - including viruses, Trojans and worms as well as other programs such as adware and spyware that find their way on to home PCs - are constantly trying to outwit security software.

Despite the risks, millions of us now rely on computer software and online support to help businesses grow, whilst the introduction of broadband has made web-surfing at home faster, cheaper and easier than ever before.

But the rise in online use is putting more households than ever before at risk from computer viruses and malicious programs designed to devastate PCs and steal personal information from them.

Over the past two years, there have been a number of high-profile cases of virus attacks on PCs worldwide - including the 2003 "Blaster" worm and "Sobig" e-mail virus which disabled computers and snarled worldwide internet traffic, and led software giant Microsoft to offer a £250,000 bounty for information about their authors.

In April this year, a virus known as MyDoom spread rapidly across millions of computers and, at one point, was accounting for one in nine e-mails globally in addition to clogging a vast number of corporate networks around the world.

And a recent study by information security provider Symantec has claimed that more than 30,000 PCs per day are being targeted and recruited into secret networks that spread unwanted "spam" e-mails and viruses.

In one day alone it’s estimated 75,000 PCs were recruited.

There have even been a growing number of cases where online users have run up enormous phone bills after becoming the victims of "pop-up" advertisements and "web diallers" - which send the user to a premium £1.50-a-minute website when they try to shut down the adverts on their screens.

And the latest virus threat, a variant of a malicious software bug known as Sdbot, even tries to install a backdoor into the computer in order to allow hackers to steal information from them without anyone knowing they have been there.

At the moment, McAfee and many other anti-virus firms say they are seeing 25-50 new viruses or variants of old ones every day, and experts have added that it is now possible for a computer virus to spread across the globe in less than 15 minutes - leaving a trail of destruction on millions of PCs in the process.

So how damaging can these viruses actually be and what kind of measures can be taken to prevent them from spreading into businesses and homes throughout the Capital?

McAFEE analyst Nick Bowman says: "There’s a number of reasons why viruses have become so prevalent. When the first computer virus appeared in the mid-1980s, it was severely restricted in terms of growth, because it could only be spread through floppy disks.

"Nowadays, thanks to the growth of the internet and e-mail, it has become far easier to send viruses between computers, and the internet is now the most prevalent way of spreading a virus across the globe.

"The fact that PCs have such a huge amount of hard disk space and memory has also meant that virus programmers and hackers have been able to create much more complex programs to infiltrate other computers. And, over the past couple of years especially, we’ve seen a lot of writing tool kits becoming available to download over the internet which effectively show anyone how to write a virus. You don’t have to be technically knowledgeable to produce an effective virus any more - anyone can do it.

"Viruses pose a huge threat to a large number of people as they can target any stored data or investment details on any personal or office computer.

"There are some viruses that can simply wipe out this kind of information and leave a hard drive completely empty, whilst there are others that can infiltrate a system and pick out important information, such as credit card details and passwords, which are then relayed back to the person that created the virus."

He goes on to say that, traditionally, viruses are man-made programs sent to a computer which reproduce and attach themselves to other programs - preventing the computer from working properly. Worms are programs which multiply by sending copies of themselves from one computer to hundreds of others via e-mail or a local network, whilst Trojans are rogue programs sent to a computer without the user’s knowledge which can then extract important information that is relayed back to the programmer.

However, Bowman says that the company has also highlighted adware and spyware programs - which fall into a category it calls "Potentially Unwanted Programs" - as a threat because many people fall victim to them without knowing they are being installed.

Adware delivers pop-up adverts inside and outside net browsing sessions, while spyware keeps an eye on the sites you visit allowing others to see what your interests are.

He adds: "Anti-virus providers such as ourselves are constantly trying to identify new virus threats and are looking at ways to try and stop them before they are unleashed on to PCs. At the moment, we are updating our software on a daily basis to match the needs of home PC users worried abut viruses.

"However, there are a lot of people who still don’t have even the basic software for identifying viruses and it is these people who are most at risk. If anyone is buying a new PC, or has one which is already linked to an internet provider or broadband service, the bare minimum that they should have is some sort of virus scanner and a firewall set up to protect their data."

ANTI-VIRUS software is readily available from high street computer stores, whilst some companies such as McAfee have products available to buy or download from their websites.

Jeremy Ward, service development director for internet security provider Symantec, adds: "Just because you haven’t heard of a big virus threat recently, it doesn’t mean that the threat has gone. There are more and more programs getting on to people’s systems every day that they don’t know about, and the programmers responsible are taking personal information from computers or using them to attack others.

"You really have to do something to protect yourself and it is vital to have an anti-virus system in place that you keep up to date. If not, you run the risk of losing everything.

"The risk is even greater for people using broadband, and these users must have firewalls in place to prevent viruses and rogue programs from getting in.

"Just remember that there is always someone trying to break into your system and you are far more vulnerable if you don’t have any protection in place."

Bowman adds: "Whatever you do, just don’t go online without a virus scanner or antivirus software - you’re only asking for trouble if you do."