Is your computer safe online?

Your computer operates under an "open door" policy. Bank account details, passwords, credit card numbers, documents and other personal information that you don't want to share with the world - they are all available to anyone else on the Internet. You probably have no idea that all the time you are online computers all over the world have a look at your computer, with hits every couple of minutes!

  • Hackers can get in, take what they want, and even leave open a "back door" so they can access your computer anytime you're online and use it to attack other computers.

  • Advertisers and other websites spy on your Internet habits by placing cookies (small files that web sites place on your computer) which then report that information, usually without your knowledge, to the cookie owner.

  • Antivirus software does nothing to secure your computer against direct attacks. Most people think that it protects them completely from Internet-borne threats. But virus protection is only as good as the latest virus definitions, which are created in response to the latest viruses. Someone (potentially many thousands of people) must be infected before the makers of antivirus software can create a defence.

Every minute that your computer is connected to the Internet, it is at risk

You Need A Personal Firewall!

In buildings, a firewall is a barrier that prevents a fire from spreading. In computers, the concept is similar. There are a variety of "fires" there out on the Internet-hacker activity, viruses, unwanted cookies, and so forth. A firewall is a system that stops the fire from spreading to your computer.

A firewall guards the "doors" to your computer - the ports through which Internet traffic comes in and goes out. The firewall only lets traffic through the ports that you have specified can be used. This has three security benefits:

  • No one can sneak into your computer through an unguarded port.

  • Programs on your computer can't use unguarded ports to contact the outside world without your permission.

  • Spam emailers can't "see" your computer so easily.

A firewall is a piece of software that monitors all incoming network traffic and allows in only the connections that are known and trusted. Port 80 is open so that you can browse web pages; port 1863 allows you to engage in instant messaging with friends; port 443 gives access to secure web pages used by online merchants to encrypt purchases.

You could manually grant or restrict access to each of the 65,535 ports available under the Internet Protocol. Every time you add a new program that requires Internet access, you would need to determine which port(s) it uses, and reconfigure your computer accordingly. You've probably got better ways to spend your time.
Firewall software takes on this burden for you, allowing access to the ports you need open, and closing off those you don't. It also makes your computer "invisible" on the Internet; if hackers can't find you, they will have a hard time attacking you.

More advanced firewall software also monitors outgoing traffic. This is crucial since malicious code spreads by accessing the Internet and pushing copies of itself to other computers (often those of your friends and family, using your email address book!).

How Does A Firewall Work?

All Internet traffic - web pages, email, audio files, and so on - are transmitted in bite-sized chunks called "packets". Each packet is addressed to a particular computer, and to a particular port on that computer. The computer baddies out there also send malicious packets out, with destructive capabilities. A firewall examines every packet that arrives at your computer and asks four questions:

  • Where did it come from?

  • What port is it addressed to?

  • Do the rules allow traffic through that port?

  • Are there any other rules the packet violates?

If the firewall gets the wrong answer to any of these questions, the packet is blocked, and your computer is safe.

Port Scanners

A technique hackers use to find unprotected computers on the Internet. Using automated tools, the hacker systematically scans the ports on all the computers in a range of IP addresses, looking for unprotected or "open" ports. Once an open port is located, the hacker can use it as an access point to break in to the unprotected computer. A good port scanner can actually scan every on-line computer in an entire (small) country in 24 hours!

Why Do I Need Program Control?

Everything you do on the Internet - from browsing Web pages to downloading MP3 files - is managed by specific applications (programs) on your computer. Hackers exploit this fact by planting "malware" - literally, evil programs - in your computer. Sometimes they send out malware as email attachments with innocent names like "screensaver.exe".

If you open the attachment, you install the malware on your computer without even knowing it. Other times, they convince you to download the malware from a server by making it masquerade as an update to a legitimate program.

Once on your machine, malware can wreak havoc in a variety of ways. It can raid your address book and send itself to everyone in it, or it can listen for connection requests from the Internet. The hacker who distributed the malware can then contact it and give it instructions, effectively taking control of your computer.

Why Do I Need Cookie Control?

Cookie control keeps advertisers from spying on your Internet habits. High security settings keep sensitive information (passwords, for example) from being stored in cookies, where they can be stolen if a hacker breaks into your computer.

Persistent cookies: a cookie that stays on your computer a long time and lets the Web site remember who you are, and what you look at, so that the next time you visit, it can customize what you see. For example, this is how shows you books you're likely to want each time you visit.

Third-party cookies: placed by someone other than the Web site host and can be used to record information about your Internet habits - for example, which advertisements you click on.

Session cookie: a cookie stored in your browser's memory cache that disappears as soon as you close your browser window. These are the safest cookies because of their short life-span.
Medium cookie control setting allows session cookies and persistent cookies, but blocks third-party cookies. This protects you from information leaks while preserving the convenient functions of cookies.

Why Do I Need Ad Control?

Ad blocking keeps unwanted advertisements from disrupting your Internet work. With a firewall you can block all types of ads or only specific types:

  • Banner and Skyscraper ads extend across the top or up the side of the Web page itself.

  • Pop/up and pop-under ads appear in a new browser window that "pops up" in front of or under the screen you're looking at.

  • Animated Ads use moving images, colour changes, and so forth.

When you visit a Web page with ads a firewall can block pop-up and pop-under ads. It's as if they didn't exist. It can also block banner and skyscraper ads if they take more than a few seconds to load. This is called performance ad blocking, and keeps advertisers from slowing down your Web experience.

The Problem With Email Attachments

Attaching files to email messages is a convenient way of exchanging information. However, it also provides hackers with an easy way of spreading viruses, worms, Trojan horse programs, and other malware.

TIP: It's a good idea never to open an email attachment unless you know the person it came from, and have confirmed (by phone or separate email message) that that person actually sent it to you. Remember hackers can alter an email message to look like it came from a friend!

Where Can I Get A Personal Firewall?

As with all software, it's a matter of personal choice what colour or flavour you like but generally they all do the same thing. Of course, we cannot recommend any particular product. Using Google or other search engines will find a selection of firewall software. Three well-known packages are: