The Day the Zombies Took Over

When a user receives hundreds of unwanted messages sent to your inbox it costs them time and effectively money. You can make a pretty good argument that this constitutes theft of services.

Recently, spammers have started stealing service on the sending end of the game also.

Spammers are increasingly taking over end-user's systems via malware to send spam. Compromised systems may become unreliable, cause network congestion, and possibly even get the company's network blacklisted - blocking email that users are legitimately trying to send. As a part-time system administrator, this poses real concerns for me. By sending from a large variety of networks, zombies can frequently bypass the antispam tool technology known as blacklisting.

How can you know if you have zombies on your network?

One easy thing to look for is unexplained network activity. If you're the last one in the office, and the traffic light is constantly on for one of the end-user workstations - might be worth checking out.

Getting a little more advanced - you should be able to setup logging on your firewall. However, it can be tedious to sort through the logs.

On the preventative side - consider locking down outgoing SMTP access to only your server. In addition, if you require SMTP authentication, you should be able to pretty much block junk mail sent by the zombie from getting off your network. If you're using Exchange, you may be able to lock down SMTP all-together.

To help minimize the impact of spam, consider installing a spam stopping software program. SpamButcher is available as an antispam software download for free trial.

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