Encrypted html emails being displayed in plain text with PGPexch.htm.pgp attachment

[Dave]

Hi all,

Some encrypted html emails I receive are shown in Thunderbird 24.5.0 in plain text with an attachment named PGPexch.htm.pgp. If I decrypt and open this file in Firefox, I see the html email as it was intended to be seen.

Is there a way to get Thunderbird/Enigmail to display this content correctly without having to open the .htm separately?

I'm running v1.6 (20131006-1849) on Kubuntu 14.04 amd64.

An edited version of the source of such an email is below to provide clues.

Many thanks!

From - Fri May 16 10:43:03 2014
X-Account-Key: account5
X-UIDL: UID18668-1279040440
X-Mozilla-Status: 0001
X-Mozilla-Status2: 00000000
X-Mozilla-Keys:
Return-path:
Envelope-to:
Delivery-date: Fri, 16 May 2014 10:42:32 +0200
Received: from [213.61.254.72] (helo=)
by X with esmtp (Exim 4.80.1)
(envelope-from <x>)
id 1WlDiq-0002Aa-CG
for X; Fri, 16 May 2014 10:42:32 +0200
Received: from X ([172.23.61.16])
by X (IBM Domino Release 9.0.1)
with ESMTP id X ;
Fri, 16 May 2014 10:42:13 +0200
Received: from exchsrv20.X ([10.199.101.70])
by X.de (Lotus Domino Release 8.5.3FP6)
with ESMTP id X ;
Fri, 16 May 2014 10:37:35 +0200
Received: from EXCHSRV22.X ([fe80::74b0:cf98:fb4f:8cae]) by
X.de ([fe80::d8f8:a0c8:c81b:d8ca%15]) with mapi id
14.01.0438.000; Fri, 16 May 2014 10:42:02 +0200
From: "X>
To: X>
References: X@exchsrv22.X
Accept-Language: de-DE, en-US
X-MS-Has-Attach: yes
X-MS-TNEF-Correlator:
x-pgp-universal-saved-content-codepage: utf-8
x-pgp-encoding-format: Partitioned
x-pgp-encoding-version: 2.0.2
x-pgp-mapi-encoding-version: 2.5.0
x-originating-ip: [141.200.177.92]
MIME-Version: 1.0
X-MIMETrack: Itemize by SMTP Server on X-EXT(Release 8.5.3FP6|November
21, 2013) at 16.05.2014 10:37:36,
Serialize by Router on X-EXT(Release 8.5.3FP6|November
21, 2013) at 16.05.2014 10:37:40,
Serialize complete at 16.05.2014 10:37:40,
Itemize by SMTP Server on X-DMZ(Release 9.0.1|October
14, 2013) at 16.05.2014 10:42:13,
Serialize by Router on X-DMZ(Release 9.0.1|October 14, 2013) at
16.05.2014 10:42:27,
Serialize complete at 16.05.2014 10:42:27
Message-ID: X@exchsrv22.X.de
Date: Fri, 16 May 2014 08:42:00 +0000
Content-Type: multipart/mixed;
boundary="Xexchsrv22X_"
Content-Language: de-DE
X-Virus-Scanned: Clear (ClamAV 0.98.1/18994/Fri May 16 05:25:17 2014)
X-Spam-Score: 1.1 (+)
Delivered-To: X</x>

--004_6B371B91DEE29A43AF3B141548CDB62302E441exchsrv22X
Content-Type: multipart/alternative;
boundary="000_6B371B91DEE29A43AF3B141548CDB62302E441exchsrv22X"

--000_6B371B91DEE29A43AF3B141548CDB62302E441exchsrv22X
Content-Transfer-Encoding: base64
Content-Type: text/plain; charset="utf-8"

LS0tLS1CRUdJTiBQR1AgTUVTU0FHRS0tLS0tDQpWZXJzaW9uOiAxMC4yLjEgKEJ1aWxkIDQ5NDAp
DQpDaGFyc2V0OiB1dGYtOA0KDQpxQU5RUjFEQndFd0QzN1RLa0FWUnR1SUJDQUREdmRqaS9mbE5O
dWdVTnJGZTA4ZXpqdXQ5UHV2UjINCj0xM0gwDQotLS0tLUVORCBQR1AgTUVTU0FHRS0tLS0tDQoN
Cg0K

--000_6B371B91DEE29A43AF3B141548CDB62302E441exchsrv22X
Content-Transfer-Encoding: base64
Content-Type: text/html; charset="utf-8"

PGh0bWw+DQo8aGVhZD4NCjxtZXRhIGh0dHAtZXF1aXY9IkNvbnRlbnQtVHlwZSIgY29udGVudD0i
CjxkaXY+Jm5ic3A7PC9kaXY+DQo8ZGl2PiZuYnNwOzwvZGl2Pg0KPC9zcGFuPjwvZm9udD4NCjwv
Ym9keT4NCjwvaHRtbD4NCg==

--000_6B371B91DEE29A43AF3B141548CDB62302E441exchsrv22X--

--004_6B371B91DEE29A43AF3B141548CDB62302E441exchsrv22X
Content-Transfer-Encoding: base64
Content-Type: application/octet-stream; name="PGPexch.htm.pgp"
Content-Disposition: attachment; filename="PGPexch.htm.pgp"; size=8663;
creation-date="Fri, 16 May 2014 08:42:00 GMT";
modification-date="Fri, 16 May 2014 08:42:00 GMT"
Content-Description: PGPexch.htm.pgp

LS0tLS1CRUdJTiBQR1AgTUVTU0FHRS0tLS0tDQpWZXJzaW9uOiAxMC4yLjEgKEJ1aWxkIDQ5NDAp
DQoNCnFBTlFSMURCd0V3RDM3VEtrQVZSdHVJQkIvOXp0ekQ2WkhrbHZnY3FrbDZvbFArNWdpTDls
UjlOY0YrOEd2Z013cll6WDZuUHNRMXUNCmNkR01lVzhIc3Y2Lys2VXlYMFpSVGt4UmZCVTlLdUZh
KzFqVWNnOVd6WGdEZ0FXa1dnPT0NCj1aWmphDQotLS0tLUVORCBQR1AgTUVTU0FHRS0tLS0tDQo=

--004_6B371B91DEE29A43AF3B141548CDB62302E441exchsrv22X--

[Patrick Brunschwig]

No, that's not possible. The attachment is classified by the sender as an attachment with binary content. Enigmail does not know what to do with it; the content is displayed by Firefox only due to the fact that the attachment name is *.htm.

[Dave]

One of my colleages uses PGP Desktop (MAC) with Outlook and it displays the same html emails correctly and automatically so I guess there is a way somehow?

[Patrick Brunschwig]

Only if you define for yourself how to interpret what to do. There is no standard for this, i.e. PGP Desktop knows what to do because it also created the message.

[Dave]

Fair enough Patrick - I was afraid that would be the cause! The sooner everything adopts the PGP/MIME standard (including PGP Desktop) the better!

Many thanks for your responses and your continued work on Enigmail.