Securing your computer from the vulnerabilities of the Internet

Ok, so you finally got rid of that clunky old “dial-up” connection and got yourself that lightning fast new ADSL (Broadband) connection you’ve been hearing so much about. No more having to dial up and make a new connection each and every time – just stay connected on line 24 hours a day – 7 days a week and you are truly part of the Internet now. No worries, right? Wrong! As soon as you are connected to the Internet in this fashion, its time to start thinking about precautions that will ensure your computer is safe against external attacks.

While the risk of being hacked over a typical dial-up Internet connection is relatively small, once you get wired to a permanent cable or ADSL Internet connection, the risk grows exponentially. Whatever method you are connected to the Internet, your privacy can be at risk.

Quite apart from the obvious security risks there is always the matter of cost. Hackers not only invade your privacy they will increase your costs immediately. Remember their activities are using your Internet connection to download and to do their work – which by the way you are paying for.

So how do I protect my home or business computer system?

If you are running a “home” or “small-office” system you might want to consider installing a piece of “smart” software called a firewall whose job is to act as a sentry between your computer system and your Internet connection. It is the firewall’s job to determine just exactly what information can validly come into or leave your computer on the Internet.

Firewalls range in price from downright reasonable (free) to very scary! We will focus on the home computer / small office system. Any good firewall should not only detect but also block any intrusion attempts. Further, a good firewall’s main emphasis should be to effectively make your computer invisible to the rest of the Internet so that others cannot view or gain access to your valuable information.

What types of people would want to attack my computer system?

There are those on the Internet who are constantly on the prowl scanning for unprotected, vulnerable systems. These hackers, whether they are hard-core or bored and unsupervised kids with too much time on their hands, continuously scan for computer addresses (IP addresses). They have varying motives from simply the fun of the challenge right on through to identity theft.

How do hackers attack or gain access to other systems?

A prime cause of system vulnerability is poor or improper setup of the file or folder sharing. A computer can be easily put at risk if you run internet-enabled software that is not properly secured. The greatest risk can come by accidentally downloading: a virus, Trojan Horse software or by unwittingly getting tricked into installing Spyware that is often bundled with legitimate programs.

Vulnerabilities of these types can potentially allow hackers to access information on your computers hardware such as your hard disk, what is being displayed on your monitor or even what you are typing into your keyboard. They can also log your browsing and online purchasing activities and habits. Often they will store their own material on your computer or take over your computer to use as a zombie to attack other computers.

Kids left to their own devices can be one of the greatest sources of security vulnerabilities. They are often unaware of the consequences of giving out private information like E-mail addresses or financial details of credit cards. Mostly they are unaware of the pitfalls that can beset the innocent when they visit dodgy websites or the methods employed by the unscrupulous on the Internet.

How do you go about “selecting” a Firewall?

There are literally hundreds of firewall packages out there. That said, it can be difficult to determine which best suits your needs. Of course the most important consideration is always how well it works and suits your computing environment. Also important is how easy (or difficult) it is to install and setup. Then of course there is always the small matter of cost.

The simplest types of firewall will attempt to block all data entering on a specific communication channel of your computer called a “port”. If you use access to a house as an analogy this would be the same as putting a lock on almost every door. For example, you might exclude all entry except that coming through the front gates. This approach to firewall technology is very restrictive as it is an all-or-nothing affair. It means that if you allow web browsing to occur, any other program, especially those such as Spyware, which uses the same port can gain access to the Internet.

The next type of firewall is more sophisticated. It allows control of which programs can access the Internet and which ports they can use to do so. You might liken this to a secure buildings where ID swipe cards are used to control access to the offices (this would be the program) and which doors they can use (this is the ports).

The more sophisticated firewalls will examine each packet of information as it is transmitted and evaluate whether it should have access either to or from the Internet. Using the same analogy as the secure building, this is more like having a security guard who stops and questions anyone who enters or leaves the building irrespective of whether they have an ID card or not. Generally these types of firewall provide the better levels of protection and security.

How do you know if your Firewall security is working correctly?

After installing a firewall it is still important to check that it truly is is working in the correct and proper fashion and that your computer really is tied down and secure. There are sites that can simulate different types of attacks and vulnerabilities. ShieldsUp! or PC Flank are two organisations that can provide this service for you if you visit their sites and carry out the appropriate instructions.

Some affordable Firewall options

• Norton Personal Firewall 2003
  www.symantec.com.au
• McAfee Firewall 4.0
  www.mcafee-at-home.com
• ZoneAlarm 3.1
  www.zonelabs.com

Without doubt the cheapest choice would be the ZoneAlarm system, it enjoys a fair degree of popularity amongst the most “budget minded” of our community. Norton is a well known and respected company with a proven track record of producing good value for money products and as such ranks well as a security device offering something from the very simple to the relatively sophisticated.

Arthur Hissey
Computer Research & Technology
www.crt.net.au