Windows on the Web- October 2001
Locking Your Window
Windows on the Web is usually focused on opening a window- a window from your computer to the wealth of information out on the web. However, the beginning of this column is going to focus on closing. In this case, it is on closing the window that outsiders use to break into your computer.
Why do this now? A number of events triggered it. In mid-September, the company where I host my own web site fell victim to the nimda worm. Because they weren't current on applying security patches to their servers, I was without e-mail for almost two days. Also in September, for about the fifth time this year, a member of NABE fell victim to one of the Melissa/Code Red type viruses. How do I know? As webmaster, my e-mail address is in a lot of member's address books. When they are hit with a worm, a copy of the worm is automatically mailed to everyone in their address book.
Luckily, either my firewall or my anti-virus software stops these from causing damage here. But it is clear that other people are being damaged. While many of you have IT departments at work to take care of security, other NABE members are their own IT departments, either at work or at home.
One other reason for talking about this know -- many of the worms/viruses of the past, such as "I Love You" or "Anna Kournikova", were bothersome but not especially destructive to your files. However, it will be relatively easy to construct these worms so that they start deleting files on your computer. Given the events since September 11, we have to be more aware of threats.
Here are steps you can take to limit your vulnerability.
Update your anti-virus signatures: It should go without saying that you need anti-virus software on a computer, especially if it connects to the Internet or shares disks with other computers. In addition, make sure the anti-virus signatures are updated frequently. At the minimum, you should be doing this weekly, but it wouldn't hurt to do it even more often. Many of the anti-virus programs can be scheduled to either check automatically for updates, or least nag you to do so.
Use a firewall: It is absolutely mandatory, if you have an always-on Internet connection, such as DSL or cable modem, to have a firewall. If you don't, then assume your computer will be compromised. Even if you don't care whether they steal your data, a zombie computer program might get planted on your computer, which can then use your computer as a platform to attack others. Still using dial-up? While you don't face the same degree of danger, a firewall can still repel many attacks. Figure 1 shows a portion of my firewall's log, showing the number of probes and attacks repelled. Symantec has a firewall product called Norton Internet Security. Zone Labs Zone Alarm can be downloaded and tried out before purchasing. Many of these firewalls work both ways -- they can also keep a rogue program already on your computer from surreptiously calling out. The new Windows XP will also have a basic firewall bundled in.
