Duplicate header field: "MIME-Version" in Read Receipts

[Steve Scotter via amavis-users]

 Spectrum Computer Solutions
331 Ansty Road
Wyken
Coventry
CV2 3FN
T. 07980 861013
F. 02476 619383
www.spectrumcs.net
info at spectrumcs.net



# uname -a
FreeBSD crimson.spectrumcs.net 9.1-RELEASE-p4 FreeBSD 9.1-RELEASE-p4 #0: Mon Jun 17 11:42:37 UTC 2013

# amavisd -V
amavisd-new-2.8.0 (20120630)

# perl -V
Summary of my perl5 (revision 5 version 14 subversion 4) configuration:

Hi all,

Over the past few months I've been receiving a lot of requests from staff to release email which has been marked as [INVALID HEADER] due to 'Duplicate header field: "MIME-Version"'.

When I take a look at the messages I see they're read receipts relating to an email a staff member has sent. (the subject has a READ: prefix).

The examples I can remember have been from large financial institutions in the UK so getting though to their IT department is unlikely from my position as a SMB IT Support person.

A censored example is available at http://pastebin.com/1qXP5suv

To my untrained eye I believe there are too many MIME-Version: 1.0 headers (lines 33 and 50) but I'm unsure if this is a problem specific to this group of senders or a wider problem. I can see from the headers that the senders organisation is using a exchange server but I can't tell what version (perhaps a incompatibility with the latest version?). Is anyone else having similar problems?

Also, is it possible to somehow prevent Amavisd sending notifications for 'Duplicate header field' against only "MIME-Version"' (eg, I still want 'Duplicate header field: "Subject"' notifications) and what would be the implications? Could anything malicious sneak though?

(I have full policy configuration backed by MySQL database)

Regards
Stephen Scotter
Systems Consultant
T. +44 (0) 7970 463925
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