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RE: A more detailed description of the Jura F90 vulnerability.
From: "Thor (Hammer of God)" <thor () hammerofgod com>
Date: Thu, 19 Jun 2008 08:06:21 -0700

So you've published what some would call 0day information on a "remotely
exploitable" vulnerability that allows one to compromise another's
workstation using the "I tried" justification?  That seems hardly
appropriate for a man of your stature, Craig.  Even if the actual risk
of exploitation is very low due to other mitigating factors, responsible
disclosure policies should be respected.  But you did manage to get some
nice press in CNET, huh?  

By the way, I'm sure you actually executed code as POC rather than just
assuming that you could based on the calls you identified by reverse
engineering the binaries, right?  I guess I'm also curious how you are
classifying this as "remotely exploitable" when what you describe in
your "detailed description" sounds more like you would have to get a
victim to go to your evil web site first or download your coffee
"recipe" somehow and feed them to the coffee maker, right?   Or is the
maker actually listening for connections and the assumption is that
people will connect it directly to the internet and not behind some NAT
device?  Given your apparent full-disclosure policy, you won't mind
sharing POC code with us, right? (even though most people don't have
your kind of money to buy a $2000 coffee machine to test it on ;).  I
think given all the attention you've received about this that the most
complete and accurate information should be made available to the
public.

t

-----Original Message-----
From: Craig Wright [mailto:Craig.Wright () bdo com au]
Sent: Wednesday, June 18, 2008 2:43 PM
To: Thor (Hammer of God); security-basics () lists securityfocus com;
bugtraq () securityfocus com
Subject: RE: A more detailed description of the Jura F90
vulnerability.


I have attempted to. They are not the easiest company to contact. I am
sending more details to the firm that tests their products. They seem
to be a shell with a large number of outsourced arrangements.

Craig


Craig Wright
Manager, Risk Advisory Services

Direct : +61 2 9286 5497
Craig.Wright () bdo com au
+61 417 683 914

BDO Kendalls (NSW-VIC) Pty. Ltd.
Level 19, 2 Market Street Sydney NSW 2000
GPO BOX 2551 Sydney NSW 2001
Fax +61 2 9993 9497
http://www.bdo.com.au/

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-----Original Message-----

From: Thor (Hammer of God) [mailto:thor () hammerofgod com]
Sent: Thursday, 19 June 2008 3:11 AM
To: security-basics () lists securityfocus com; bugtraq () securityfocus com
Subject: RE: A more detailed description of the Jura F90
vulnerability.

Have you shared all of this with the manufacturer first?

t

-----Original Message-----
From: Craig Wright [mailto:Craig.Wright () bdo com au]
Sent: Tuesday, June 17, 2008 11:10 PM
To: security-basics () lists securityfocus com;
bugtraq () securityfocus com
Subject: A more detailed description of the Jura F90 vulnerability.


The issue is a lack of input validation. OWASP would be a great
learning exercise for the coders on this product. It seems to be
assumed that only trust-worthy users will connect only to trust-
worthy
sites. I could not find any evidence of input validation.

Through the magic of Web Scarab and Paros proxy, one can capture the
Internet communications used by the F90 Internet Connection Kit
software. What you soon see is that the software does not account
for
either bypassing the local application and changing the input or in
spoofed and re-directed sites.

The software does not validate the site it gets the information from
nor does it sufficiently validate the input to the software.

At the moment as I think there are so few people as crazy as I am
who
actually have to have a gadget just as it is Internet connected;
this
is not likely to become a widespread attack vector.

The software is an oversized web proxy with other stuff to connect
to
the coffee machine thrown in. Jura did not make the assumption that
an
evil attacker could purposefully modify and publish "evil" coffee
"recipes.

I have been taking the updated SANS () Home 610 course. I have a GREM,
but
Lenny and the other guys have added an additional component to the
Reverse Engineering Malware Course. So I had to take it.

The course focuses on analysing and reversing malware, but IDA and
Olly
work on binaries of all types and the bad combination of a bottle of
good resiling and 9 coffees after midnight is not a good
combination.
Hence I decided to attack my coffee maker and the control software.

There are certain aspects of code (like the ever faithful GETS()
function) that should be beaten from existence. Others need to be
securely configured such that all the required variable fields are
entered correctly (see SPRINTF()). Unfortunately the coders at Jura
did
not consider that "bad people" would ever attack a coffee maker ;).

There are 2 main attacks that I have noted,
1       Loading a malicious setting or recipe into the device
causing
a
"coffee overflow" etc.
2       More seriously, not validating the input correctly coupled
with
a lack of authorisation of the source and nothing to stop invalid
data
at the host means that malformed strings can be fed to the software
that can either crash the system or if crafted correctly run a
binary
on the host.

So, as most people who check this list I no doubt know, not
validating
input is bad. Trusting the web as you have a piece of custom
software
that is closed source and a belief that users are all nice is bad.

Regards,
Craig Wright GSE-Compliance

PS for DMCA compliance reasons I would state that I was not
reversing
the software, but rather inputting unusual coffee recipes that had a
strange binary flavour ;)

Craig Wright
Manager, Risk Advisory Services

Direct : +61 2 9286 5497
Craig.Wright () bdo com au
+61 417 683 914

BDO Kendalls (NSW-VIC) Pty. Ltd.
Level 19, 2 Market Street Sydney NSW 2000
GPO BOX 2551 Sydney NSW 2001
Fax +61 2 9993 9497
http://www.bdo.com.au/

The information in this email and any attachments is confidential.
If
you are not the named addressee you must not read, print, copy,
distribute, or use in any way this transmission or any information
it
contains. If you have received this message in error, please notify
the
sender by return email, destroy all copies and delete it from your
system.

Any views expressed in this message are those of the individual
sender
and not necessarily endorsed by BDO Kendalls. You may not rely on
this
message as advice unless subsequently confirmed by fax or letter
signed
by a Partner or Director of BDO Kendalls. It is your responsibility
to
scan this communication and any files attached for computer viruses
and
other defects. BDO Kendalls does not accept liability for any loss
or
damage however caused which may result from this communication or
any
files attached. A full version of the BDO Kendalls disclaimer, and
our
Privacy statement, can be found on the BDO Kendalls website at
http://www.bdo.com.au/ or by emailing
mailto:administrator () bdo com au 

BDO Kendalls is a national association of separate partnerships and
entities. Liability limited by a scheme approved under Professional
Standards Legislation.




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