Advisory ID: SYSS-2020-015 Product: ABUS Secvest Hybrid module (FUMO50110) Manufacturer: ABUS Affected Version(s): N/A Tested Version(s): N/A Vulnerability Type: Authentication Bypass Using an Alternate Path or Channel (CWE-288) Risk Level: High Solution Status: Open Manufacturer Notification: 2020-04-03 Solution Date: - Public Disclosure: 2020-07-30 CVE Reference: CVE-2020-14158 Authors of Advisory: Michael Rüttgers, Thomas Detert, Matthias Deeg (SySS GmbH) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Overview: The ABUS Secvest Hybrid module is an expansion module that allows to bridge between the ABUS Secvest alarm panel [1] and further wired systems. Some of the supported features as described by the manufacturer are (see [2]): " * The hybrid module turns wireless into wired and wired into wireless. And alarm systems into combined security systems. By connecting to the ABUS wAppLoxx, the property benefits from intelligent access management while simultaneously eliminating false alarms. * In combination with Secvest, the hybrid module can also be used to implement numerous smart home scenarios. Garage doors, household lighting or rolling shutters can be operated in this way, for example. " Due to missing security features regarding confidentiality and integrity of the used radio communication, different radio-based attacks are possible. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Vulnerability Details: The hybrid module does not have any security mechanism that ensures confidentiality or integrity of RF packets that are exchanged between the ABUS Secvest alarm panel and the ABUS Secvest Hybrid module. Thus, an attacker can spoof messages of the ABUS Secvest Hybrid module based on sniffed status RF packets that are issued by the ABUS Secvest Hybrid module on a regularly basis (~2.5 minutes). One of the suggested use cases in [3] (page 27) is the link of a wAppLoxx to the ABUS Secvest alarm panel via the ABUS Secvest Hybrid module. In the intended use case, this allows to disarm the ABUS Secvest panel simultaneously when access by the wAppLoxx system is granted to a properly authenticated user. By spoofing the ABUS Secvest Hybrid module RF messages, an attacker is able to bypass the authentication of wAppLoxx in such a system configuration without the need of any user interaction. For clarity, the authentication of the wAppLoxx cylinder itself is not influenced by this attack, and an attacker still needs to find access to the protected object. The input channels of the ABUS Secvest Hybrid module are simply mapped to a 4-byte field in the RF packages. Modifying those bytes allows an attacker to simulate any change on the ABUS Secvest Hybrid module inputs. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Proof of Concept (PoC): Michael Rüttgers and Thomas Detert developed a PoC tool using the RFCat-based radio dongle YARD Stick One [4] that allows spoofing RF packets and thus bypassing the authentication of wAppLoxx in the described system configuration. They provided their tool including documentation and source code to SySS GmbH for responsible disclosure purposes. SySS GmbH could successfully perform the described authentication bypass attack against an ABUS Secvest wireless alarm system used with the ABUS Secvest Hybrid module (FUMO50110). The described spoofing attack is demonstrated in the SySS proof of concept video titled "ABUS Secvest Spoofing Attack" which is available on the SySS YouTube Channel "Pentest TV" [7]. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Solution: SySS GmbH is not aware of a solution for this reported security vulnerability. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Disclosure Timeline: 2020-04-03: Vulnerability reported to manufacturer 2020-07-30: Public release of security advisory ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ References: [1] Product Website for ABUS Secvest Wireless Alarm System https://www.abus.com/eng/Home-Security/Alarm-systems/Secvest-wireless-alarm-system/Alarm-panels-and-kits/Secvest-Wireless-Alarm-System [2] Product Website for ABUS Secvest Hybrid Module https://www.abus.com/uk/Home-Security/Alarm-systems/Secvest-wireless-alarm-system/Control-devices-and-extensions/Secvest-Hybrid-module [3] Installation Instructions and User Guide https://www.abus.com/var/ImagesPIM/d110001/medias/docus/22/FUMO50110_BDA_INT_1_3.pdf [4] Product Website YARD Stick One https://greatscottgadgets.com/yardstickone/ [5] SySS Security Advisory SYSS-2020-015 https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2020-015.txt [6] SySS GmbH, SySS Responsible Disclosure Policy https://www.syss.de/en/news/responsible-disclosure-policy/ [7] SySS Proof of Concept Video: ABUS Secvest Spoofing Attack https://www.youtube.com/watch?v=PidiWcB0tmI ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Credits: This security vulnerability was found by Michael Rüttgers and Thomas Detert. Mr. Rüttgers and Mr. Detert reported this finding to SySS GmbH where it was verified and later reported to the manufacturer by Matthias Deeg. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 website. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Copyright: Creative Commons - Attribution (by) - Version 3.0 URL: http://creativecommons.org/licenses/by/3.0/deed.en