The recent spate of replicating e-mail viruses like the ILOVEYOU points to a problem network administrators have fighting the current generation of computer viruses. Recent experiences with rapidly proliferating viruses suggest that the approach of monitoring incoming mail for dangerous content has an inherent limitation. Virus protection software can only detect viruses that it knows about, and these programs are unable to stop executable content that hasn't been seen before. Moreover, the virus definition has to be communicated to clients using that virus software.
Nearly all of the most dangerous viruses are delivered by executable content: macros in applications, program scripts like Visual Basic, and binary files. It's especially difficult to deal with embedded mail content, and exponential growth of transmission using messaging system address books. Eventually what's required is that your company adopt a policy on the transmission of executable content in e-mail and stick to it. For example, if your company CEO wants to communicate with all of the company employees and sends a note with a Word file, then that message would have to be cleared first by a system administrator. It should be a rule that no one opens an application file with macros from an unknown party. Rules like this will be built into the next generation of virus software.
You can purchase products like WQuinn's FileScreen 2000 software that automatically prevents any file type such as ".vbs" (Visual Basic Script) files or .exe (executable or application) from being copied to Windows NT/2000 servers. That kind of policy would stop viruses such as the "ILOVEYOU" virus and last year's "Melissa" virus. This software also allows files to be blocked by name.
It may seem extreme to implement a policy-based virus protection program, but in these uncertain times, it is probably very prudent. Insurance is only good when you need it, and the time you save may be your own.
Barrie Sosinsky (firstname.lastname@example.org) is president of consulting company Sosinsky and Associates (Medfield MA). He has written extensively on a variety of computer topics. His company specializes in custom software (database and Web related), training and technical documentation.