/beyond/security/article.php/3573781/Firewalling.htm Firewalling


By Vince Barnes

There is a plague, represented by two variants, which originates with miscreants who have nothing (or not enough) constructive to do with their lives. I am of course, talking about hacker attacks and viruses.

When we think about hackers these days, we are usually thinking of the folk who try to break into a computer system. That's not what the word traditionally meant. I dug out my 1979 Webster's Dictionary to see what it had to say about hacking. The book predates the common use of the Internet and although it gives no less than thirty-six different meaning for "hack", organized into nine categories, not one of them mentions a computer or anything related to it. How quickly things change! One meaning struck me in particular: "to chop or cut in a clumsy or unskillful way."

In the world of computers, hacking used to refer to the manner in which programmers would sit for hours on end at a console on a big old mainframe computer and work and work, foregoing sleep and food (but never foregoing coffee!) until a problem that had reared its ugly head was solved and the machine was humming along nicely once again. I was once just such a programmer and I know from experience that if anybody asked me how it was going, or what I was doing to solve the problem, I would invariably answer with something like "I don't know. Now leave me alone!" It wasn't that I actually didn't know, or that I was being anti-social; it was simply that I couldn't afford to have my concentration broken. Nevertheless, it created the impression of "unskillful chopping" at the problem, groping for a solution. If they eventually came to the conclusion that I was a hero for averting the crisis, I wouldn't know -- I was home sleeping!

These days, the impressions are just the opposite. Hackers are seen as using skill, but to ruin systems, not to solve problems. To my way of thinking, skill is something used in a creative process. When the objective is destruction, not creation, there can be no "skill" involved. What knowledge there may be involved in the task, loses all value because of its objective, and consequently loses its right to be called skill. I don't consider a burglar to be a "skilled home protection engineer".

I apply the same thinking to the so-called skills of the programmer who writes viruses.  We have used the medical or biological analogy because of the manner in which the code can replicate itself, but I take it further. A disease is a disease. The programmer who writes a virus has diseased "skills". The only thing to be done is to correct the situation -- remove or disable the disease.

Corporations around the world spend huge amounts of money to protect themselves from the plague of these two diseases. When you connect to the Internet, you also need protection. Do not fall into the trap of thinking that since you turn off the computer most of the time, never bring in diskettes or CDs that were recorded on someone else's computer and are careful not to open email attachments, that you are immune. It only takes a moment for something to find its way through an open hole. You have got to close them up. A hole, by the way, in this context is any mechanism by which a feature of the software (including the operating system) in a computer system can be exploited for other than its originally intended use.

Make no mistake -- there is no complete block; no sure fire protection. With the number of people having destructive intent working on finding holes and communicating with each other over the net, there will be new holes discovered every hour of every day. What you can do, is to harden your system as much as possible; make it as difficult as possible to exploit and provide the most up-to-date virus protection you reasonably can.

Windows XP offers a much higher degree of protection than earlier versions, incorporating file security options and a built-in firewall. If you're using XP, check out "firewall" in help and make sure it's active in your system. If you have applied Service Pack 2 (and by now, you certainly should have!) the built-in firewall is on by default. For other systems I suggest you get a commercial firewall program such as Symantec's Norton Internet Security/Norton Personal Firewall (Windows/Mac), McAfee's Personal Firewall Plus (Windows) or Computer Associates eTrust suite. There are also some pretty good products from smaller vendors such as BlackIce Defender (Windows). Computer Associates, Symantec and McAfee are also vendors of the most popular antivirus products. Another is Panda Software. For both firewall products and anti-virus products I think there is value in using products from large vendors. They have sophisticated, automated update mechanisms and a lot of people involved in keeping the updates up-to-date. Also, the larger the user base, the quicker any problem in the product itself will be discovered (and hopefully, fixed!) All of the above mentioned vendors fit this category. Pay the (relatively small and definitely worth it) license fee and use the automatic update features to keep your products in fighting fit form. I do not recommend using any shareware products for security. (!!)

Once you rid yourself of disease, all that is left is ease!

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