Viruses getting through

[Paul Welsh]

For the past few weeks I've had viruses getting through - the pesky ones
that claim to be flight confirmations, bank statements or some such with
small .zip files attached.  I'm sure you know about them.  Some are tagged
as spam but not all.

The headers of a recent one show that the message is classed as clean:

Received: from [217.45.162.11] by etrn.borusantelekom.com; Wed, 17 Sep 2008
09:17:36 +0000
Message-ID: <01c918a6$39323800$0ba22dd9 at ghw>
From: "Lindsey Avila" <ghw at borashipping.com>
Subject: Statement of fees 2008/09
Date: Wed, 17 Sep 2008 09:17:36 +0000
MIME-Version: 1.0
X-welshfamily-MailScanner: Found to be clean
X-welshfamily-MailScanner-SpamCheck: not spam, SpamAssassin (not cached,
	score=0.407, required 6, autolearn=disabled,
	XMAILER_MIMEOLE_OL_4B815 0.41)
X-welshfamily-MailScanner-From: ghw at borashipping.com
X-Spam-Status: No

I'm using clamav and bitdefender but although updated with the latest
definitions, it's probably ineffective because it's the free version v7.1.
Running freshclam yields this:

# freshclam
ClamAV update process started at Wed Sep 17 21:41:04 2008
main.cld is up to date (version: 48, sigs: 399264, f-level: 35, builder:
sven)
daily.cld is up to date (version: 8272, sigs: 28579, f-level: 35, builder:
ccordes)

Here's the version of clam:
# clamscan -V
ClamAV 0.94/8272/Wed Sep 17 21:16:02 2008

I'm running MailScanner version 4.71.10.

I did browse the archive of this list but couldn't find the answer.  Any
help appreciated.