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List:       ntbugtraq
Subject:    Possible Bug in MAPISP32 Mime-decoding
From:       Jason Adam Young <jason_young () NCSU ! EDU>
Date:       1997-12-03 14:33:13
[Download RAW message or body]

I need someone who knows more about this than I do to check this out.

This started when I received a PGP-Signed message encapsulated
in Mime-format from the NT Security List.  The NT Security list
now includes a disclaimer about unsubscribing from the list, that
includes the MIME message boundary (a '-' ) in the note.

Apparently, attaching a note in the form:

----- -----
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
CCCCC
----- -----

Encoding it in base64 and attaching it to a message with the
NT Security header, or a '-' followed by any alphanumeric
apparently causes MAPISP32 to go to 100% CPU utilization and
'hang' on popping mail when trying to POP3 a message of this format.

I have reproduced this on both Win95 and WinNT with Outlook 97, with
the Internet Mail Patch, with two different pop accounts, each from two
different POP3 servers, and with different messages encoded in a similar
fashion.  I have not tested Outlook Express or Exchange Client.  The one
message I sent to a user who uses Outlook 98 did not cause this problem.

Apparently the message between the delimeters needs to be of the
size above:  (ie. a PGP signature seems to do this well)

Encode the above in base64.
----- -----
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
CCCCC
----- -----

becomes:

LS0tLS0gLS0tLS0NCkFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFB
QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUENCkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJC
QkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkINCkNDQ0NDDQotLS0tLSAtLS0t
LQ==

Adding a '-' + some alphanumeric to the string:

-a
LS0tLS0gLS0tLS0NCkFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFB
QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUENCkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJC
QkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkJCQkINCkNDQ0NDDQotLS0tLSAtLS0t
LQ==

and setting your headers:
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: base64

Seems to do it.  You have to send this from a mail program that can send
the
raw data and headers and not mess with the message.  I used the Unix 'send'
command.

I did search the Microsoft KB and found nothing along these lines, and I
searched in a couple of other places.  It is probably known, and it may be
something with my configuration, but it has occurred on multiple platforms,
with multiple messages, with Outlook97.

If someone who knows a little more about this could verify it or if
Microsoft
is aware of it, and has some fix, that would be great. I don't have the
knowledge/time to track this down any further.

If this has all somehow been visited before, please let me know.

Jason Young
-----------------------------------
Jason Adam Young
Computing Consultant
NC State University

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