Mulberry, SSLv3 and POODLE

[Christer Mjellem Strand]

Greetings,

As I'm sure you've all heard, this week's OpenSSL POODLE[1]
vulnerability has caused sysadmins worldwide to scramble to disable
SSLv3 on their servers. Although in the bigger picture this is probably
a good thing, for Mulberry it causes a bit of trouble, since it
supports TLS with STARTTLS, but otherwise only SSLv3 and SSLv23. Most
IMAP and SMTP servers thankfully support STARTTLS, but no such luck
with CalDAV, CardDAV or LDAP.

In order to continue remaining functional, Mulberry will have to work
with TLSv1. Ideally it should simply use the system OpenSSL libs
without too much magic inbetween (which could allow for TLSv12,
elliptic curve and such nice things), but at a bare minimum, TLSv1
needs to work.

Anyone else hit by this? Anyone already working on it? Anyone up for
the task?

(I am not a developer, unfortunately)

[1] <http://poodlebleed.com/>

[Cyrus Daboo]

Hi Christer,

--On October 18, 2014 at 5:49:08 PM +0200 Christer Mjellem Strand

As I'm sure you've all heard, this week's OpenSSL POODLE[1] vulnerability
has caused sysadmins worldwide to scramble to disable SSLv3 on their
servers. Although in the bigger picture this is probably a good thing,
for Mulberry it causes a bit of trouble, since it supports TLS with
STARTTLS, but otherwise only SSLv3 and SSLv23. Most IMAP and SMTP servers
thankfully support STARTTLS, but no such luck with CalDAV, CardDAV or
LDAP.
In order to continue remaining functional, Mulberry will have to work
with TLSv1. Ideally it should simply use the system OpenSSL libs without
too much magic inbetween (which could allow for TLSv12, elliptic curve
and such nice things), but at a bare minimum, TLSv1 needs to work.
Anyone else hit by this? Anyone already working on it? Anyone up for the
task?
(I am not a developer, unfortunately)

A code change is needed to make it work properly. However, if you are using
a local preferences file what you can do is grep that file for the string
"SSLv3Real" and change that to "TLSv1". That will trick Mulberry into using
the "STARTTLS - TLSv1" option that is otherwise disabled in the preferences
dialog.

For anyone wanting to tweak the code, here is the diff I am currently using
(note line numbers will be way off as I have some other uncommitted changes
in that file right now - but the general approach is to switch to the v23
method to use all the time but use the SSL_OP_NO_XXX to turn of the
undesirable methods):

Index: Mulberry/Sources_Common/Mail/Network/CTLSSocket.cp
===================================================================
--- CTLSSocket.cp (revision 491)
+++ CTLSSocket.cp (working copy)@@ -477,11 +617,9 @@
{
case 1:
case 4:
+ case 2:
m_ctx = ::SSL_CTX_new(::SSLv23_client_method());
break;
- case 2:
- m_ctx = ::SSL_CTX_new(::SSLv3_client_method());
- break;
case 3:
m_ctx = ::SSL_CTX_new(::TLSv1_client_method());
break;
@@ -493,7 +631,7 @@
}

// Work around all known bugs
- ::SSL_CTX_ctrl(m_ctx, SSL_CTRL_OPTIONS, SSL_OP_ALL, NULL);
+ ::SSL_CTX_ctrl(m_ctx, SSL_CTRL_OPTIONS, SSL_OP_ALL | SSL_OP_NO_SSLv2
| SSL_OP_NO_SSLv3, NULL);

[Christer Mjellem Strand]

Hi Cyrus, thanks for responding so quickly.

Post by Cyrus Daboo

Post by Christer Mjellem Strand
As I'm sure you've all heard, this week's OpenSSL POODLE[1]
vulnerability has caused sysadmins worldwide to scramble to
disable SSLv3 on their servers. Although in the bigger picture
this is probably a good thing, for Mulberry it causes a bit of
trouble, since it supports TLS with STARTTLS, but otherwise only
SSLv3 and SSLv23. Most IMAP and SMTP servers thankfully support
STARTTLS, but no such luck with CalDAV, CardDAV or LDAP.
In order to continue remaining functional, Mulberry will have to
work with TLSv1. Ideally it should simply use the system OpenSSL
libs without too much magic inbetween (which could allow for
TLSv12, elliptic curve and such nice things), but at a bare
minimum, TLSv1 needs to work.
Anyone else hit by this? Anyone already working on it? Anyone up
for the task?
(I am not a developer, unfortunately)

A code change is needed to make it work properly. However, if you
are using a local preferences file what you can do is grep that
file for the string "SSLv3Real" and change that to "TLSv1". That
will trick Mulberry into using the "STARTTLS - TLSv1" option that
is otherwise disabled in the preferences dialog.

I tried this before posting, and while this does seem to work in terms
of forcing it to use STARTTLS - TLSv1, unfortunately this doesn't
really help since the protocols affected are the same ones that don't
use STARTTLS (HTTP et al).

David R Bosso kindly tipped me off off-list however that the SSLv23
method, where available, does include TLSv1. This has fixed the problem
for me in Linux, where Mulberry is built against a relatively recent
version of OpenSSL. In Windows (using 4.0.8), however, only the
STARTTLS - TLSv1 and SSLv3 optons are available - not the SSLv23 option.

Post by Cyrus Daboo
For anyone wanting to tweak the code, here is the diff I am
currently using (note line numbers will be way off as I have some
other uncommitted changes in that file right now - but the general
approach is to switch to the v23 method to use all the time but use

[..]

Thanks for that - I'll be sure to include these the next time I
rebuild. I also intend to play around with TLS Interposer[1], which I'm
already using for several pieces of server-based software that lack
configurable ciphers. Looking at its source, it seems to me the
necessary changes to add support for ECDHE ciphers would be a matter of
a few lines, which would seem a worthwhile effort for someone touching
this code.

This still leaves the Windows version though - I wouldn't have a clue
where to even begin trying to build that myself.. :| The last time I
tried the 4.0.9a1 version I quickly ran into installer problems and
reverted - would that version perhaps include changes that would allow
the SSLv23 option to be used?
If not, are there any plans to make a rebuilt Windows download
available? Does anyone even have a functioning development environment
for Mulberry in Windows anymore? :}

Thanks again.

[1] <https://netfuture.ch/tools/tls-interposer/>

[John C Klensin]

--On Saturday, 18 Oct 2014 22:08:37 -0400, Cyrus Daboo

Post by Cyrus Daboo
A code change is needed to make it work properly. However, if
you are using a local preferences file what you can do is
grep that file for the string "SSLv3Real" and change that to
"TLSv1". That will trick Mulberry into using the "STARTTLS -
TLSv1" option that is otherwise disabled in the preferences
dialog.

Cyrus,

I just searched my local preferences file (Mulberry 4.0.8,
Windows XP) for "SSLv3Real" and found nothing like it. Several
instances of "SSLv3" but no "Real".

Suggestions, or is this the point at which the Windows version
has to be declared terminally ill?

best,
john