MailScanner fix for Exchange TNEF vuln?

Ghetti, Ron Ron.Ghetti at
Fri Feb 13 20:02:34 GMT 2009

-----Original Message-----
From: mailscanner-bounces at [mailto:mailscanner-bounces at] On Behalf Of Cedric Devillers
Sent: Friday, February 13, 2009 9:50 AM
To: MailScanner discussion
Subject: Re: MailScanner fix for Exchange TNEF vuln?

Well, i can't tell you if it's related to some outlook/exchange version
or config, but here that's easily reproductible here.

Without TNEF (winmail.dat thing), outlook receive meeting requests as
plain mail messages. You don't see the fancy buttons (accept, decline,
etc) and users complain of other missing features (can't remember
exactly which one). With TNEF replacement disabled, everything is
automagically working again.

TNEF is used by outlook for special features, that's why it's also a
dangerous thing.

Jonas Akrouh Larsen wrote:
>> I'm not sure that's entirely acurate.  I have replace TNEF enabled, but
> have received meeting requests from 3rd parties outside our system.  I've
> never had any complaints...
> Same here. We have replaced TNEF for over a year, and have never had issues
> with outlook meeting requests or calendar bookings.
> And all our clients user outlook/exchange.

Same Here, All our users run Outlook.
I checked my settings and the TNEF replacement is enabled, I'm not
Sure if that was the default or not.
We do occasionally have a meeting not received complaint.
But it's not a regular thing and I haven't persued it. Instead, we've typically told them that 
internet email "doesn't work well" with microsoft outlook calendar.
Usually if they retry sending the meeting later, they will go through ok.

Why am I not surprised someone has hacked a microsoft product...


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> Jonas Akrouh Larsen
> TechBiz ApS
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