GNU/Linux Desktop Survival Guide by Graham Williams
Desktop Survival Project Home Preface Advocacy History Distributions Installation Basic Survival Wajig Audio AbiWord APM Backup Bash Booting Cameras CD Chinese ChRoot Clock Commercial Conference Management Configuration CRON CVS Databases DIA Directories Disks Documentation DVD Email Eye of Gnome Evolution File Systems Firewalls Floppy Disks Fonts Ghemical GIMP Glade Gnome GnuCash Gnumeric GQView Graphics Groups HTML Editors ImageMagick Initialisations on Booting Java KDE Kernels Keyboard Konqueror KVM Switch LaTeX Log System Login Magellan Mathematics Memory Modems Mounting Devices MS/Windows Music MySQL Nautilus Networks NFS NT File System OpenOffice.org Oracle Packages Partitions Passwords PDF Photos PPP Presentations Printing Python R Remote Desktops Rsync Samba Scanning Science Security SH File System Sketch Spell SPlus Spruce SSH SUDO Subversion Swap Themes USB Video Virtualization Web Word X XML Sample Installations Troubleshooting Index

Viruses

Debian Packages: clamav clamav-freshclam

The clamav package can be used to check email for viruses. The virus data will be updated automatically if clamav-freshclam is installed.

The clamscan command can also be used used with procmail by using a script (in this case, clamfilter.pl from http://www.everysoft.com/) to run clamscan on each message with a procmail entry like:

  :0fw
  | clamfilter.pl
  :0:
  * ^X-Virus-Found: yes
  clam-`date +%Y-%m`

The actual script to add the appropriate X-Virus-Found header is:

#!/usr/bin/perl -w
#
# ClamFilter 1.0
# by Matt Hahnfeld (http://www.everysoft.com/)
# Requires perl, clamscan, procmail, and this script. 
#
# Add these lines to your .procmailrc:
#
# :0fw
# | /usr/local/bin/clamfilter.pl
# 
# This script is public domain. 
#

use strict;
use File::Temp 'tempfile';

&main();
exit 0;

sub main {
  # Set up a temporary file for the original message
  my ($tmpfh, $tmpfn) = tempfile( UNLINK => 1 );
  -w $tmpfn or die 'Could not open temp file!';

  # Pass 1: Write out the temporary file
  while (<STDIN>) {
    print $tmpfh $_;
  }
  seek($tmpfh, 0, 0);

  # Pass 2: Scan the message
  open CLAMSCAN, "/bin/cat $tmpfn | /usr/bin/clamscan --stdout --recursive --mbox - 2>/dev/null |" or die 'Could not open clamscan!';
  my $clamstatus = qq|X-Virus-Found: yes
X-Virus-Status:
 ------------------------------------------------------------
 Virus Scan Status:
 ------------------------------------------------------------
|;
  while (<CLAMSCAN>) {
    $clamstatus .= ' ' . $_;
  }
  close CLAMSCAN;
  $clamstatus .= qq| 
 ------------------------------------------------------------

|;

  # Pass 3: Print out the message
  my $bodyflag = 0;
  while (<$tmpfh>) {
    if (! $bodyflag and $_ eq "\n") {
      if ($?) {
        print $clamstatus;
      }
      else {
        print "\n";
      }
      $bodyflag = 1;
    }
    else {
      print;
    }
  }
}