Building an E-mail Virus Detection System for Your Network
The basic outline of the system consists of using Bash scripts, metamail, grep, the Obtuse Systems' smtpd product, Samba and a command-line virus scanner. A flowchart-style diagram can be found in Figure 1. The Obtuse Systems' SMTP store and forward package is freely available at www.obtuse.com/smtpd.html. The current version as of this writing is version 2.0. The virus scanner I chose was McAfee Virus Scan for UNIX/Linux, but there are quite a few others to choose from. Some are free and some are not. Do make sure you choose one that sets exit status codes based on what it finds and that is well supported with frequent signature updates.
