I've noticed this on a few occassions and just had another instance of it.  Periodically, spamfilter seems to allow an email to slip through that contains a black listed keyword within the body of the email.  At first I thought perhaps my server was  overloaded and spamfilter just skipped over the keyword filter somehow, but after catching several of these I began to take a deeper look into what's going on.

After investigating and scratching my head a few times, I decided to go onto the actual mail server and open the corresponding .mai file with notedpad for a truely raw view of the email in question.  Here's what I found out...Outlook is rendering the emails as plain text.  Webmail also renders the emails as "normal" looking emails, however, upon inspecting the .mai file the email appears to be using some sort of uuencoding through out the body of the message that is allowing it to completely slip through despite that it appears to be laced with plain text keywords that I have black listed.  Anyone got any ideas on how to combat these?  See sample below.

Received: from noah ([10.14.10.18]) by v-sources.com with MailEnable ESMTP; Thu, 05 Jan 2006 19:34:40 -0500
Received: from 151.203.109.90 by v-sources.com (LogSat Software SMTP Server) Thu, 5 Jan 2006 19:34:37 -0500
Message-ID: <IIBDOMPFDHDCOEFHNEDPNPOECGAB.merrill_gorman_lk@fyi.net>
From: "Merrill Gorman" <merrill_gorman_lk@fyi.net>
To: fdickey@v-sources.com
Subject: Stock Market Standouts
Date: Thu, 05 Jan 2006 22:33:44 +0000
MIME-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: base64
X-Server: LogSat Software SMTP Server
X-SF-RX-Return-Path: <merrill_gorman_lk@fyi.net>
X-SF-HELO-Domain: amfam.com
X-Read: 1

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