Malicious Mobile Code

Preventing Viruses in Windows

Preventing viruses in a Windows world means implementing the lessons we learned from DOS and adding a few new ones.

Install Antivirus Software

An up-to-date antivirus software package is a convenient way to prevent most computer virus infections.

Disable Booting from Drive A

Disabling booting from drive A will prevent boot viruses from infecting your machine, unless they are placed there by a dropper or multipartite program.

Don’t Run Untrusted Code

When friends and business associates send me unexpected or untrusted files with the exploitable extensions listed in Table 3-1, I usually delete them right away. If I suspect the file is legitimate, I will try to open the file in a nonthreatening way. For example, if someone sends me a rich text file (RTF), I will open it up in WordPad. There are known exploits of .RTF files in MS Word, so I open the file up in an application with less of a chance to cause harm. Using this philosophy I have never been infected by an email bearing a virus or Trojan. Of course, if I’m sent a file that I’m expecting and I have taken the appropriate security precautions (such as disabling document macros, running a virus scanner, etc.), then I feel safer when opening the file.

Install Service Packs and Updates

Installing the latest service packs and updates is a great way to close known security holes. Although slow to respond, Microsoft fixes weaknesses in their operating systems with every service pack. Install the in-between ...