Potential issue with docx format and Clam

Jeff A. Earickson jaearick at colby.edu
Mon Apr 20 14:56:59 IST 2009

Found this one...  The setting I needed was:

Maximum Archive Depth = 3

I changed this to 8 and things started working for the Office 2007 crowd.

Jeff Earickson
Colby College

On Mon, 20 Apr 2009, Martin Hepworth wrote:

> Date: Mon, 20 Apr 2009 13:47:23 +0100
> From: Martin Hepworth <maxsec at gmail.com>
> Reply-To: MailScanner discussion <mailscanner at lists.mailscanner.info>
> To: MailScanner discussion <mailscanner at lists.mailscanner.info>
> Subject: Re: Potential issue with docx format and Clam
> Jeff
> what happens if you use Clamd rather than the module so you can update
> quicker (no reliance on module maintainers releasing a new version) and MS
> children are smaller and startup faster?
> -- 
> Martin Hepworth
> Oxford, UK
> 2009/4/20 Jeff A. Earickson <jaearick at colby.edu>
>> Julian,
>> I'm forwarding along a note from our support desk people, who seem to
>> have uncovered an issue with Office 2007/2008 docx file formats and
>> the ClamAV recursion level.  In my case, I am running MS 4.75.9-2 with
>> ClamAVmodule Maximum Recursion Level = 8
>> Adam's detective work below suggests that this setting may be too low
>> for Office 2007/2008 docx attachments.  Anybody else seen this?
>> (Time for me to upgrade to the latest stable version, or the latest beta).
>> Jeff Earickson
>> Colby College
>> ---------- Forwarded message ----------
>> I did some experimenting with this situation [rejections of email with
>> "Report: MailScanner: Message contained archive nested too deeply" messages]
>> and here is what I found:
>> - As you may or may not know the new Office 2007/2008 file format is really
>> just a renamed .zip file containing other files and folders that make up
>> the
>> document.
>> - If you insert an object into a .docx that is, for instance, a PowerPoint
>> slide it is inserted as a .pptx (again, just a .zip with a different
>> extension).
>> - If that slide contains an inserted Excel table, it is inserted as a .xlsx
>> (.zip).
>> - So if you add all those up you have the original .docx, which contains a
>> folder called "embedded", in that folder is a .pptx file, inside that is a
>> folder called "embedded", in that folder is a .xlsx file, inside that is a
>> series of files and folders.  So all that added up is 7 layers.
>> I was able to duplicate Todd's error with my own .docx, .pptx and .xlsx,
>> but
>> I noticed that it had to be all three.  If I tried to email a .docx with
>> just a PowerPoint slide embedded it went fine.  And if I tried to email a
>> .pptx with an embedded Excel Table that went fine too.  So it seems as
>> though we may need to adjust some settings on MailScanner to allow for this
>> type of file to pass because as we convert more and more people to Office
>> 2007/2008 we are going to be more likely to run into these types of
>> situations.
>> ------------
>> Adam Nielsen
>> Faculty and Staff Support Center
>> x4222
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