The following article appeared in the Wednesday, June 20, 2001 issue of The Munising News. If you're on a fast connection, you can view a scan of the article. The scan is 83 Kb in size. By the way, in my article, I reference the story of a denial of service attack on Steve Gibson. Some of Steve's views on the subject are somewhat controversial. You can learn more by visiting The Register and reading the article titled You both make good points, but we're still leaning in Steve's direction. That article links to two related articles that you should also look it in order to really get your arms around the controversy. Regardless of the controversy though, my point still stands, you need a firewall. Period.
Protect Your Broadband Connections
At 8:00 PM, Friday, May 4, 2001, Gibson Research Corporation in Laguna Hills, CA came under electronic attack. Their Internet connection was being flooded with garbage data, so much so that not enough bandwidth remained for legitimate traffic, and the grc.com web site all but disappeared from the net. It took Steve Gibson, President of Gibson Research, 17 hours to recover from that first attack and get his web site back online. Over the next several weeks, he was attacked numerous times again before he was finally able to research the attack and work with his Internet service provider to devise a defense against it. The perpetrator of this attack? A 13-year old child, aided by 474 unwitting Windows PC users, many of whom were connected to the Internet by cable modem. For the complete story of the attack on Gibson Research Corporation, point your web browser to http://grc.com/dos/grcdos.htm [page no longer available - ed].
How did these 474 Windows PC users aid unwittingly in this attack? The answer is simple. They connected their PCs to the Internet without taking some basic steps to protect themselves from attack. Probably using a virus-like mechanism, hackers were able to plant remote control attack programs on these PCs. Once in place, hackers could remotely command the PCs to attack Gibson Research's Internet connection while the PC's owners were blissfully unaware that they were contributing to a crime in progress. Of the 474 PCs that Steve Gibson identified as participating in the attack, 104 were @Home cable modem users, 51 were Road Runner cable modem users, 20 were America Online subscribers, and the list goes on.
Computers connected to the Internet via cable or DSL are prime targets for hackers because of the "always-on" nature of the connection, and because of the high-bandwidth that hackers can utilize remotely after compromising such a machine. If you have cable Internet or DSL Internet, and you haven't taken steps to protect yourself from outside attack, you are not only putting your own data at risk, but you are placing other Internet users at risk as well.
What can you do to protect yourself? Two things. Install virus protection software, and install a firewall. The need for virus protection is well-known, so I won't go into that in this article. Firewalls are what I want to talk about. A firewall is a combination of hardware and software that isolates your computer, or your home network, from the outside Internet. All Internet traffic passes through the firewall, and the firewall software gives you control over what traffic to allow and disallow. Firewalls have been used for years by companies connecting their internal networks to the Internet. Home users connecting to the Internet are susceptible to the same attacks as large companies, and consequently need the same sort of protection. Even if you get a remote control attack program, such as the one used to attack Gibson Research, on your computer, a good firewall will prevent hackers from making any use that program.
Firewalls for home users come in two basic flavors. There are hardware firewalls and software firewalls. A hardware firewall not only provides protection, but a great deal of convenience as well. They are more than just a firewall, they are a firewall/router combination. A typical setup, for a cable modem user, would be to have coaxial cable coming into a cable modem, Ethernet from the cable modem to the firewall device, and then Ethernet cables to one or more computers in the home. Computers within the home can share the Internet connection, and share files and printers freely, but are protected against unauthorized access from outside. If you're interested in installing a home network that includes a hardware firewall, read my article on the subject at http://www.oreilly.com/news/cablemodem1_0101.html.
Software firewalls are good solutions when you have a single PC, or when you just don't want to spend a lot of money. A software firewall is a program that you install on your PC, and which allows you to control communications over your Internet connection. Because they run on your PC, software firewalls typically provide you a more granular level of control than do hardware firewalls. You can, for example, allow only certain programs on your PC to communicate to the outside world. Sygate has a software firewall that that is free for personal use [No longer true - ed]. Zone Labs also offers free firewall software, ZoneAlarm, that you can download from http://www.zonealarm.com. [Look under "Products & Services" for ZoneAlarm's "Basic Firewall" product - ed]
If you have a cable or DSL Internet connection, take the time to purchase (or download) a firewall. Take the time to install it. Learn how to use it. You'll be more secure yourself from outside attack, and Steve Gibson just might rest a bit easier at night.
Jonathan Gennick is [or was at the time of writing - ed] a computer book author and editor with O'Reilly & Associates. He has written several articles related to home networking issues.