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Credit:
The information has been provided by Ollie Whitehouse.
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When a device is docked via USB it uses the connection like a standard network interface. Once an IP address is obtained the device will initially communicate via RAPI with the host on port 990/TCP. It will go through a small handshake routine and then, if appropriate, challenge the host for the devices PIN or Password. When the user supplies this PIN/Password on the host it will be obfuscated via XOR with a fixed key of E9 and then sent over the USB network connection to the device for verification.
This process results in two vulnerabilities. Firstly, should an attacker be in a position to sniff the host computer's network connection he will be able to recover the PIN/Password. Secondly, an attacker can spoof the docking process of the device in an attempt to get the user to supply his PIN/Password.
If we take a sample packet:
0000 82 00 60 0f e8 00 80 00 60 0f e8 00 08 00 45 00 ..`..... `.....E.
0010 00 32 59 95 40 00 80 06 49 31 a9 fe 02 02 a9 fe .2Y.@... I1......
0020 02 01 03 de 05 d0 e8 c0 cb c0 56 2e 41 75 50 18 ........ ..V.AuP.
0030 fa 6a 91 dd 00 00 08 00 d8 e9 db e9 da e9 dd e9 .j...... ........
We can see that byte 36 is the length of the password (8 bytes) followed by a NULL. After which is the password obfuscated with E9, this is immediately apparent due to the use of a UNICODE string for the password so every second byte is 0x00 XOR 0xE9 which equals 0xE9.
Vendor Response:
There is a security vulnerability that could allow for Information Disclosure. An attacker would need to do one of two things, either tether a cable to the USB sync cable or bind a network sniffer to the USB-RNDIS interface - requiring administrative permissions on the workstation hosting the AS connection.
Recommendation:
Windows Mobile 5.0 Please see your handset manufacturer to obtain the update customized for your device. This issue is fixed in Windows Mobile 6.
CVE Information:
CVE-2007-5460
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