Fighting Viruses and Worms

Topics on this page

• Keep Your Computer Clean - It Is Your Responsibility
• Be Skeptical
• Set Your Operating System to Automatically Update
• Have Anti-Virus Software and Set It to Automatically Update
• Be Ready to Rebuild
• If Your Computer Does Get Infected

Keep Your Computer Clean - It Is Your Responsibility

It is UW policy that all computers connecting the UW networks should be well managed to minimize the chance they will get infected. This policy applies no matter what computer you are using (office, portable, or home) and no matter how you connect (by modem from home, by wireless in a lecture hall, from your personal ISP account, or by plugging in to a wall connection on campus).

If you do get infected, you should view it as a very serious problem:

• An infected computer is a hazard to the UW networks and other UW computers.
• You have a responsibility to promptly clean your computer.
• Your connection to UW networks will be blocked if your computer is the source of virus and worm attacks on other computers. To be able to get to the Internet again you will have to clean your computer (probably rebuild it) and then have your connection unblocked.

Be Skeptical

Most viruses and worms need help to infect your computer. You can avoid helping them by doing the following:

• Do not open unexpected email attachments. Even attachments in messages from people you know may be infected because viruses often fake From: addresses.
• Do not download unknown programs, such as free screensavers.
• Do not trade lots of unknown files, such as with peer-to-peer programs like Kazaa. The more unknown files you download, the more likely that some of them contain viruses or worms.
• Do not believe amazing offers and unlikely stories. You really do not have a distant cousin in France (or wherever) who wants to give you millions of dollars if you only send him your bank account number.

Set Your Operating System to Automatically Update

Viruses and worms try to take advantage of known weaknesses in operating systems. In many cases, patches to these weaknesses are available. The safest approach is to configure your operating system to automatically install patches as they come available.

Have Anti-Virus Software and Set It to Automatically Update

McAfee VirusScan anti-virus software for Windows computers is available for download to all UW faculty, staff, and students at no charge. McAfee Virex is available for Macintosh computers.

The anti-virus software must have current data on viruses to be able to detect the latest attacks. It is strongly recommended that you configure your anti-virus program to automatically update so your always have the latest data.

Be Ready to Rebuild

Even when you have taken all the right steps, it is still possible for your computer to get infected. Maybe you are fooled by a nice message to open an infected attachment. Maybe a virus attacks using some new method before data is available for your anti-virus program to detect it. You may have to rebuild your computer, a task which is much easier if you plan ahead. Always have the following at hand:

• Operating system install disks
• A disk with all the operating system updates. At present, the simplest way to get such a disk for Windows computers is to obtain a copy of the Microsoft Windows SP2 update disk from Microsoft. Many computer stores, including the University Book Store, also have limited supplies of the SP2 update disk.
• Install disks for all the software you use
• Backup disks for all your own files

If Your Computer Does Get Infected

You will know your computer is infected if it begins running sluggishly, displays unexpected error messages, freezes, or simply stops working. If a virus is using your computer to send spam or to attack other computers, UW Technology will turn off your UW network connection, another sure sign your computer is infected.

Your anti-virus program (if it is properly installed and up-to-date) will try to clean things up, but there are some new viruses that are very hard to remove (See Microsoft's I Got Hacked. Now What Do I Do? technical note). In such cases it is usually best to erase your harddisk and completely reinstall your operating system, software, and files.

When you do rebuild a system, it is critical that you install the operating system updates BEFORE you reconnect to the network. Without the updates your system is likely to immediately become reinfected.