Security Advisory: Multiple Smartphones MMS Notification Sender Obfuscation
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Discovered by: Michael Mueller a.k.a. c0rnholio
Contact: c0rnholio on domain netcologne.de
Advisory Homepage: http://www.silentservices.de/adv04-2009.html
Vendor Status: not contacted
Fixes / Workarounds: none known
Discovery Date: June, 2008
Public Disclosure: 11.09.2009

Description:
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A MMS Notification is part of the MMS communication flow. Usually an 
originator sends and mms via a service provider (SP). After uploading the 
message to the SP, the recipient gets a MMS notification from the SP with 
information like originator, subject and URL of the content. In some mobile 
carrier networks it is allowed to send MMS notifications directly from one 
mobile unit to another.

Some Smartphones fail to properly display the originator of this kind of 
message which leads to a sender obfuscation.

Impact:
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This attack can be used in combination with social engineering to mislead 
the recipient to access the resource specified in the content URL of the MMS 
notification message. If the receiving device MMS client is configured 
improperly this could lead to automatically download whatever content is 
specified in the content URL. MMS clients which do not allow access to 
content URLs other that the providers MMS proxy should be safe from the 
content, but are still vulnerable to the sender obfuscation.

In addition this attack can be used to send spam and hate SMS.


Tested Devices:
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The following devices have been tested and found vulnerable for this kind of 
attack:
It is very likely that other devices and vendors are also vulnerable to this 
attack.

-  Blackberry (Tested on BB 8800, Firmware: 4.5.0.37)
The BlackBerry fails device fails to properly display the originating number 
and displays whatever information is defined in the originator and the 
subject field of the MMS notification.

-  Windows Mobile (Tested on WM5, WM6, WM6.1, WM6.5)
A Windows Mobile driven device fails to properly display the originating 
number and displays whatever information is defined in the originator and 
the subject field of the MMS notification.

-  Sony Ericsson W890i, W810i
The Sony Ericsson W890i and W810i device fails to properly display the 
correct originating number and displays whatever information is defined in 
the originator and the subject field of the MMS notification.


PoC:
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The following PDU can be sent to an affected device:

UDH: 05 04 0b 84 23 f0
Message:
7c 06 03 be af 84 8c 82 98 31 32 33 34 00 8d 90 89 0e 80 45 76 69 6c 20 48 
34 78 30 72 00 96 67 6f 74 20 72 30 30 74 3f 00 8a 80 8e 01 56 88 05 81 03 
09 3a 80 83 63 68 65 63 6b 20 79 6f 75 72 20 6d 6d 73 20 63 6c 69 65 6e 74

The above PDU will display as follows (example on Windows Mobile target):

Sender: Evil H4x0r
Subject: got r00t?

Use pduspy to send it. In addition HushSMS Version 1.0 will be available 
soon for Windows Mobile devices for further tests.