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Computer security used to mean making sure that the door was locked on your way out of the house. Now, thanks to the internet, security means protecting your computer from unknown electronic assailants as well.
At first, this job seems very daunting. Newspapers are full of headlines about the latest virus doing the rounds or the latest company to get hacked.
Remember that these kind of headlines can't be taken at face value; they play on our fears, without giving us the help that we need.
We've taken it upon ourselves to set the record straight and give you practical advice on how to protect your computer from online threats.
Our first lesson is don't panic: internet security isn't quite as hideous as it sounds. So, forget the hype, make a cup of tea and we'll talk you through everything you need to know.
Probes and general attacks
Every time you connect to the internet, your computer is assigned an IP address by your internet service provider (ISP). This gives your computer a unique address when it's online and everyone else who's online can see it.
Without an IP address, web servers wouldn't know where to send web pages when you try to open one in your web browser. Unfortunately, hackers can also use your IP address to target your computer.
The most common approach taken by hackers is to try and connect to random machines on the internet and probe them for security weaknesses.
The process is similar to a thief walking down a street checking the doors of parked cars; sooner or later, he or she will find one that's unlocked.
Protecting your computer against this kind of threat requires the installation of a personal firewall such as the excellent (not to mention free) ZoneAlarm from www.zonelabs.com.
A firewall's job, quite simply, is to look at all incoming and outgoing internet communication (or 'traffic') and to block the unauthorised kind.
You can think of a firewall as a border guard at customs checking passports but only allowing those carrying a valid passport to travel either in or out of the country.
ZoneAlarm and other personal firewalls add extra protection by only allowing specific applications access to the internet.
ZoneAlarm does a good job automatically picking these applications, including Internet Explorer and Outlook Express. However, you will still find the odd annoying dialogue box asking if you want to allow an application access to the internet.
FIREWALL APPLICATION CHECKLIST
Most good firewall software will prompt you when an application tries to access the internet, giving you the chance to let it through or block it.
While most applications are clearly identified, some are cryptically named. Here's a list of the most popular applications with cryptic names that need access to the internet on most PCs.
AOL Instant Messenger - aim.exe
Generic Host Process for Win32 Services (required for Windows' internet access) - svchost.exe
Microsoft Outlook - outlook.exe
MSN Messenger - msnmsgs.exe
Outlook Express - msimn.exe
TCP/IP Ping Command - ping.exe
Windows Messenger - msmsgs.exe
Windows Media Player - wmplayer.exe
Viruses and Trojans
Trojans, viruses and worms are the most common forms of attack and generate the most headlines. All three are programs designed to damage your computer, but they work in slightly different ways.
A Trojan is named after the famous wooden horse in Greek mythology and is a dangerous application masquerading as a safe one. Trojans are commonly used to introduce software that allows hackers to remotely control your computer.
A virus works in a similar way to a biological virus, in that it hides away on unused parts of floppy disks or inside innocuous files in order to get unwittingly transferred to another computer.
Once a computer has been 'infected', the virus then spreads by copying itself to other disks and files.
Thanks to the internet, few people exchange files on floppy disk and viruses are no longer the threat they used to be. Worms, on the other hand, thrive on the internet.
Worms are usually called viruses for simplicity's sake, but they are technically different. A worm spreads over a computer network and usually requires some user intervention to activate them.
The most common worms arrive as emails with misleading attachments; an unsuspecting user then opens the attachment and triggers the worm.
Caution and common sense can stop any Trojan, virus or worm in its tracks. Use a good antivirus application and keep its virus signatures up to date. We recommend Panda Antivirus from www.pandasoftware.com, which was reviewed as part of our antivirus software test.
Try not to automatically open attachments in emails from people you don't know and pay careful attention to the file extension on attachments in emails from people you do. Most worms arrive hidden in Word or Excel documents or as attachments with a .vbs file extension.
Some of the smarter worms can automatically run if you preview a message. The best thing to do is turn off the preview pane in your email application. In Outlook, select Preview pane from the View menu. In Outlook Express select Layout from the View menu and remove the tick from the 'Show preview pane' box.
To ensure safety between people you correspond with, why not try arranging a system? For example, never send Word documents but instead use Rich Text Format (RTF). You'll be able to keep all of your formatting but this file type is unable to hold the worm macros that can be hidden away in Word files.
If you have to send executable (.exe) files, send them inside a password-protected Zip file. Either agree on a password beforehand or send it in another email. This way you can ensure that the file hasn't been tampered with.
Finally, don't fall for hoax emails. If you receive an email telling you to delete some files because you have a virus, don't believe it even if it quotes reputable sources for the warning.
Antivirus companies do not send emails of this kind and, even if they did, do you really think they'd ask recipients to forward it to everyone they know to get the message out there?
If you receive an email like this, check your antivirus company's website for information or look at the Virus Hoax Site at www.vmyths.com.
Spyware
Spyware is a term coined by internet users to refer to an application that secretly gathers information on you and your computer, and then passes it onto someone.
It is typically bundled as a hidden component of freeware or shareware software downloaded from the internet.
Spyware is generally harmless but its covert nature makes it an unwanted addition to most people's PCs. Some spyware also monitors the websites you visit and this may have privacy implications for some people.
There are several ways to protect against spyware. First, before you download a new application, type its name into the Spy Checker website at www.spychecker.com.
This will let you know whether the application is safe or not. Second, get hold of a spyware detection tool. We recommend Ad-aware from www.lavasoftusa.com, but there's a more complete list of tools on the SpywareInfo website at www.spywareinfo.com.
Pop-up windows
It seems as though every website in the world now has dozens of windows that spring out of nowhere, advertising products you don't want or just trying to get you to install software you don't need.
Although some of this software can be harmful, most pop-up windows are just plain annoying.
Combating them requires dedicated software to detect and block the windows before they pop up. This software is typically bundled with a full suite of internet protection applications.
We recommend McAfee Internet Security 5 from www.mcafee.co.uk, or Norton Internet Security 2003 from www.symantec.com.
But you can download a free pop-up stopper called, interestingly enough, Pop-Up Stopper from www.panicware.com.
Premium-rate diallers
A new trick, especially for pornography websites, is to install a program that changes your modem dial-up settings to a premium-rate telephone number, so that you're charged an extortionate amount each time you connect to the internet.
Premium-rate diallers are usually installed unwittingly. One false click can redirect you to an unsavoury website that appears with myriad pop-up windows.
Click on the OK button displayed in one without reading its message and you've just changed your dial-up settings to a premium-rate number. It's that easy.
Besides steering clear of sites that employ such underhand tactics, the best advice is not to automatically click buttons in pop-up windows without first reading their contents.
Failing that, you can usually uninstall any accidentally installed software using Add/Remove Programs in Control Panel.
Some premium-rate diallers are written in a foreign language, which can make messages on installation or removal difficult to understand.
If you are in this position then AltaVista's Babelfish service - named after the translating fish in Douglas Adams's Hitchhiker's Guide to the Galaxy - can do the translation for you. It's not perfect but you will get the gist of the message.
Email spoofing
Email 'spoofing' allows an email address to be faked so that it appears as though one person is actually another. It's very easy to do and is commonly used by spammers to avoid detection.
For example, if they send you an email that appears to come from your own email address, you can't reply to it and reporting it is tantamount to reporting yourself.
Spammers will also use this technique to send spam to people from your email address.
If you start getting replies to messages that you didn't send, don't worry; your email account hasn't been hacked, it's just email spoofing in operation. Just email your ISP to inform it of the problem and it can track down where the messages originated.
IP address broadcasting
Some pop-up adverts warn you that your computer is 'broadcasting' an IP address that hackers can use to access your PC. This is true: it is and they can.
The full story, however, is that every computer connected to the internet is 'broadcasting' its IP address. If they weren't, the internet would grind to a halt pretty quickly, since visible IP addresses are essential for its operation. Providing you have a good firewall installed, you have nothing to worry about.
Offensive material
While the internet is full of useful and educational information, it's also full of highly offensive material.
This is particularly worrying when children use the internet so, in many cases, parents will want to restrict how their children access the internet.
Internet Explorer has built-in protection through the Internet Content Rating Association service at www.icra.org/about/.
This is a voluntary scheme which relies on responsible website owners to properly rate the content they provide so that Internet Explorer knows which websites to block.
You can turn this feature on by selecting Properties from the Tools menu of Internet Explorer. Select the Content tab and click on the Enable button to choose which sites to block.
As there are plenty of websites that don't conform to this service, for total peace of mind you are better off buying an application to do the job.
Norton Internet Security 2003 contains the software, although there are plenty of alternatives.
Remember that software is not infallible so proper education, especially for children, is a must. After all, if you tell children not to talk to strangers, then similar rules must apply online.
Take a look at the Internet Watch Foundation's website here for a good guide to online safety.
Online shopping
Online shopping, we're led to believe, is fraught with danger and hackers tapping our internet connection to get our credit card numbers. Great story, shame it's not true.
Without recourse to a Trojan, a hacker isn't able to spy on your internet connection and take information from it.
Website servers can be hacked though, and information stolen from them and, while it doesn't happen that often, it does happen.
To ensure complete safety, make sure that any website from which you plan to buy goods offers a secure service when it comes to entering credit card information.
Secure sites are prefixed by 'https' in your browser's address bar and will display a padlock icon in its status area along the bottom of its window.
If you're worried about using your credit card online, even with a secure site, remember that you're probably only too happy to read out its number over the phone, or hand the card over to a stranger in a shop or restaurant.
Conclusion:
Whatever the threat, defending yourself online requires both discipline and software. Always start with a manual process and back this up with the relevant software.
For ease of use, not to mention saving money, we would recommend buying either McAfee Internet Security or Norton Internet Security 2003. Both packages contain antivirus, firewall, pop-up ad blockers and parental controls for the bargain price of £50.
JARGON BUSTER
Attachment: A computer file, such as a word-processor document or spreadsheet, sent along with an email message.
Dialogue box: A small window that pops up to display or request information.
Dial-up: A component of Windows that allows PCs to connect to the internet using a modem and a telephone line.
Extension: The three-letter code at the end of a filename that indicates the type or format of the file.
Firewall: A system that prevents unauthorised access to a computer over a network, such as the internet.
Freeware: Software, often downloadable from the internet, which is then free for you to keep and use.
Hacking: The slang term used to describe illegal access of computer systems by unauthorised users.
IP address: The unique numeric address of a computer on the internet.
ISP: Internet Service Provider. A company that provides you with access to the internet.
Macro: An automated series of commands or operations that can be run at anytime. For example, if you always carry out a series of operations on your text to put it into a certain typeface and size, then you can set up a macro to perform this function.
Modem: A device that enables two computers to communicate with each other over a telephone line.
Networks: A way of connecting several computers and printers so that they can share data.
RTF: A common file format used to transfer files between different word-processing programs. It preserves most of the formatting of a document.
Server: A computer on a network (such as the internet) that stores shared information.
Shareware: Programs that you can try out free before deciding whether to buy them or not.
Signature: A unique 'fingerprint' used by antivirus software to detect and identify viruses.
Spam: Junk email sent to large groups of people offering such things as money-spinning ideas, holidays, and so on.
Virus: A malicious computer program designed to cause at best annoyance and at worst damage to computer data.
Web browser: A software program developed for navigating the internet, particularly the world wide web.
Zip file: A file or files that have been compressed using a program like PKZip or WinZip to save disk space or to make them quicker to email. Bitmap image files compress particularly well.
See also:
All Online
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