Where There's Smoke, There's Not Always Fire
Here are some common-sense rules to help you determine if you're infected with a virus, worm, Trojan horse, or other malefic software.
- Keep a close eye on your machine. Is it running more slowly than usual? Shut down all applications. Is there Internet or communications activity occurring anyway? If you're not running any software that transmits information, yet your machine is generating traffic, you've probably caught something.
- If unexplained activity is occurring, disconnect from the Internet. You might simply close down your modem session, disconnect your network cable, or take whatever action is required to prevent any outgoing infected messages from leaving your machine. If there is no such unexplained activity, you needn't disconnect.
- Don't necessarily believe reports from others that you're infected. As with the incident covered here, check with people you know and trust -- as long as they're in your address book, or represented in whatever database drives further infection -- to confirm a report from somebody you don't know. In most cases, infections aren't incredibly picky about who gets infected next.
- Whenever a new infection gets loose, you must update your antivirus software or obtain some kind of diagnostic tool to help you figure out if you're infected or not. Unfortunately, the newest -- and often, most dangerous -- viruses may not be incorporated into your antivirus software until a day or two after infections are discovered (sometimes, it may take even longer).
- Read what you can about the virus, and look for telltale signs of infection that you can spot. With the Nimda virus, that means files named readme.exe or readme.eml, or files with an .eml extension in general. If you can't find any such files, chances are good that you don't have the related virus, either.
If you can pass all these checks without obtaining evidence of infection, you're probably OK. But going through these motions is important, and you don't want to cut corners or skip steps along the way. Because one untreated virus on the Internet can infect hundreds or thousands of other machines, it's irresponsible not to take reports seriously. In fact, it's also a good idea to keep up with news about viruses and other security threats, so you can avoid infection or other potential sources of concern or downtime in the first place.