CHERRY B.UNLIMITED AES JD-0400EU-2/01 Crypto Issues / Replay Attacks
Posted on 30 July 2016
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Advisory ID: SYSS-2016-031 Product: CHERRY B.UNLIMITED AES Manufacturer: Cherry GmbH Affected Version(s): JD-0400EU-2/01 Tested Version(s): JD-0400EU-2/01 Vulnerability Type: Cryptographic Issues (CWE-310) Missing Protection against Replay Attacks Risk Level: Medium Solution Status: Open Manufacturer Notification: 2016-04-11 Solution Date: - Public Disclosure: 2016-06-29 CVE Reference: Not yet assigned Authors of Advisory: Matthias Deeg and Gerhard Klostermeier (SySS GmbH) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Overview: CHERRY B.UNLIMITED AES is a wireless desktop set consisting of a mouse and a keyboard. The manufacturer describes the product as follows (see [1]): "CHERRY B. UNLIMITED AES combines secure data transmission and an advanced energy supply in a design which has been thought through to the very last detail. For high professional requirements and security both at home and in the workplace." Some of the key benefits of CHERRY B.UNLIMITED AES are (see [2]): * Data transmission using 128-bit encryption, complying to Advanced Encryption Standard (AES) * USB cable charging function for both keyboard & mouse - even when in use * High-quality, pre-charged NiMH batteries from GP with a very low self-discharge * Almost interference-free wireless 2.4 GHz technology (range of up to 10 metres) * 3-button mouse: infrared sensor and adjustable resolution (1,000/2,000 dpi) with ergonomic side panels * Multi-station capability operation of several wireless products in one room * Easy to install, requiring no technical knowledge * Mini USB receiver * Keyboard awarded the "Blauer Engel" environmental seal Due to an insecure implementation of the encrypted data communication, the wireless keyboard CHERRY B.UNLIMITED AES is prone to replay attacks. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vulnerability Details: The SySS GmbH found out that the wireless keyboard CHERRY B.UNLIMITED AES is prone to replay attacks. 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 at will causing the same effect as the original data communication. 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 CHERRY B.UNLIMITED AES 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. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Proof of Concept (PoC): The SySS GmbH could successfully perform a replay attack as described in the previous section using a software-defined radio. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Solution: According to information from the manufacturer Cherry GmbH, the reported security issue will currently not be fixed in affected products. The written statement in German from Cherry GmbH regarding this and other reported security issues is as follows: "Nach Prufung der von Ihnen festgestellten 'Sicherheitsschwachstellen' haben wir uns dazu entschlossen, die AES Verschlusselung bis auf weiters nicht weiter mit den Produkt zu promoten. Derzeit arbeiten wir an einem Nachfolgeprodukt. Wie bisher, empfehlen wir Kunden mit hohen Sicherheitsanfordungen ein kabelgebundenes Produkt zu verwenden. Je nach Anforderung, auch mit CC-Zertifizierung." The English translation of this statement is: "We have examined the 'security flaws' you reported to us. As a result, we decided, until further notice, to no longer refer to AES encryption in order to promote the affected product. At the moment, we are currently working on a successor product. As we already did in the past, we recommend to our customers having particularly high security demands using wired products which, depending on the requirements, should be CC certified." ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclosure Timeline: 2016-04-11: Vulnerability reported to manufacturer 2016-04-12: Manufacturer acknowledges e-mail with SySS security advisory 2016-05-24: Response from manufacturer with information about the reported security issue and rescheduling of the publication date in agreement with the manufacturer 2016-07-04: Received written statement from manufacturer concerning the reported security issue 2016-07-29: Public release of the security advisory ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ References: [1] Data sheet for CHERRY B.UNLIMITED AES http://cherry.de/PDF/EN_CHERRY_B_UNLIMITED_AES.pdf [2] Product website for CHERRY B.UNLIMITED AES http://cherry.de/cid/wireless_keyboards_CHERRY_B_UNLIMITED_AES.htm?rdeLocaleAttr=en&WT.mc_id= [3] SySS Security Advisory SYSS-2016-031 https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2016-031.txt [4] SySS Responsible Disclosure Policy https://www.syss.de/en/responsible-disclosure-policy/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Copyright: Creative Commons - Attribution (by) - Version 3.0 URL: http://creativecommons.org/licenses/by/3.0/deed.en -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCgAGBQJXmxnjAAoJENmkv2o0rU2rW48QAKGdpX0rOt7EGa0naxGWA6UQ sucDvRFhsB+RG1LR2FuqP4d7xUbIsKDm4mpnlBQA6pA+3+ZzeBDuTx31Na1/Alui lp54Z48+tRkC70pnvPJH7P7GrR1RT/3dlt6ypeCv7pA7SKfzvalLL1KnQ624UmZ0 Ta8D0I0TMGI8Z5yamsineT1WHRqSgnxE1tNtl2FEjrkXFRDRB+OrxSVUt/26G1zJ LT1JzD+G+xjwAr5WJUO2P2dnEI+N6FlrgqaFJKH3KuAUKNcPtnY41hyp7RqL5VXa j6AZKFLQqRhZ4MrfR3NudQmaN8ksS0F0sBwsNFBZ6JyLhd+IwxBPR2WuNXKBgZ8X Rn+/TLIkhV6PXYwq9jhqok1wFEMLjMPDCjnDMBXMaHO1XwvfV8Sugg+5QrhE+4US 65afUq6UgWdWahwRbfpv71HGv0GWsjLISycS3unfLdNYtIeS0GCDEyZxq1PTioI1 tT/510oWY/5Bz7OdOkirMrpP2XHeWjQQSOz/LTxtwbInjC5/gHBgHwoxui8YzxI1 4IushgdjPG/G9gYWclRx6VcLPrexDy3szXEuDX6LeVePt2+ybayL0WEKRw3+HNey 32r3g4fMwRKlb+90hI+YzLYEforapVh5jgZRR1TKuOvUkCghY98os8dOhT+C2lgK Fs7Qn4mKZe/iD2vYlgqP =rRuZ -----END PGP SIGNATURE-----
