1.
IoT LPWAN security
Sigfox & LoRaWAN
Mikael Falkvidd
KnowIT Secure Insight 2018-05-08

2.
About Mikael Falkvidd
80+ published articles inChapter leader Core team member
Independent consultant,
Falkvidd Holding AB
Past positions:
Development Team Lead, OP5
IT Consultant, Accenture
Product Owner, Ericsson
Solution Architect, Ericsson

3.
Key takeaways
● An overview of what LPWAN, Sigfox and LoRaWAN is and why they are
important
● What security mechanisms do they provide?
● Raise curiosity: How do I attack/inspect LPWAN traffic?

4.
What is LPWAN? (1)
Low Power
● 25mW/14dBm RF output (wifi is 100mW/20 dBm, 3G is 2000mW/33 dBm )
● 2+ years on single lithium cell
● 10+ years on 2xAA
Wide Area
● 15-40 km radius per base station / gateway
● Sub-GHz ISM band (868/902/915 MHz depending on region)
Network
● This is where it get interesting from a security standpoint :-)

5.
What is LPWAN? (2)
Message-oriented
● 1 uplink message every 10 minutes max*
● Message size max 12 bytes (Sigfox) or 51–255 bytes (LoRaWAN)**
Limited downlink
● No confirmation
● Downlink always initiated by uplink - no unsolicited traffic
● Sigfox: max 4 messages per 24h, max 8 bytes each
● LoRaWAN: 10 messages per 24h, max 51–255 bytes each
Low-cost: Sigfox connectivity costs 15 EUR per year and device for 1 device.
~1EUR per year and device for 50,000 devices (10%-1% of cost with Telia IoT)

6.
Sigfox and LoRaWAN main
differences Sigfox LoRaWAN
Coverage - global 45 countries, 803M people 90+ countries
Coverage - Sweden 60% of population
Local (city-wide) networks
exist
Base stations / gateways Always owned by operator
Anyone can put up a
gateway, hardware cost from
~200EUR
Backend Owned by Sigfox
Local providers, TTN (partly
open source), open source,
DIY

7.
Security areas
● Physical device
● Radio communication
● Base stations / gateways
● Gateway to backend system
● Backend system
● Backend to application
communication
● Application

8.
Physical device attacks
● Destroy it
● Extract keys
● Modify firmware
LoRaWAN and Sigfox use per device keys, so compromisation of one device
impacts only that device and its data. The rest is your responsibility:
● Physical protection
● Use secure elements to protect keys
● Signed firmware updates* / verify firmware integrity

9.
Radio communication - Sigfox
● Each Sigfox device is provisioned with a unique symmetrical authentication
key
● All messages to from the device are protected by a MAC using a key
derived from the symmetrical key, providing authenticity and integrity.
● All messages include a sequence counter, to prevent replay attacks
● Sigfox can provide confidentiality but does not require encryption. Device
makers can add Sigfox-provided encryption as part of certification, or add
their own flavor.
● Sigfox’s goal is to have each location covered by at least 3 base stations, to
increase availability / be more jamming-resistant.

10.
Radio packet format - Sigfox
+--------+--------+--------+------------------+-------------+-----+
|Preamble| Frame | Dev ID | Payload |Msg Auth Code| FCS |
| | Sync | | | | |
+--------+--------+--------+------------------+-------------+-----+
● Preamble: 19 bits
● Frame sync and header: 29 bits
● Device ID: 32 bits
● Payload: 0-96 bits
● Authentication: 16-40 bits
● Frame check sequence: 16 bits (CRC)

11.
Base stations - Sigfox
● All Sigfox base stations have a Trusted
Platform Module (TPM), which manages
encryption keys and verifies the base
station’s integrity.
● The operating system uses Secure Boot
● Communication with the backend
system is done through VPN. The VPN
key is stored in the TPM.

12.
Sigfox backend and your application
● Sigfox data centers adhere to SSAE16/ISAE3402 SOC-1 Type II - ISO
27001 - PCI-DSS - FACT - ISO 9001-2008 - ISO 50001
● “State-of-the-art solutions have been deployed to ensure the integrity,
availability and confidentiality of [devices’ authentication keys as well as
traffic metadata.].” *
● Communication between the Sigfox backend and your application uses
HTTPS.
● Your application is (of course) your responsibility

13.
Radio packet format - LoRaWAN

14.
LoRaWAN keys in TTN
Network session key (NwkSKey)
● used for interaction between the Node and the Network and routing
● check the validity of messages
Application session key (AppSKey)
● encryption and decryption of the payload
● payload is encrypted between the device and the Handler component of TTN, which
you will be able to run on your own server (LoRaWAN 1.1).
When dynamically activating a LoRaWAN device (OTAA), these keys are re-generated on
every activation. If you statically activate your device (ABP), these keys stay the same
until you change them.

15.
Real-world examples
Securitas Direct uses a Sigfox device to report GSM jamming attacks. They have
deployed more than 1.6M units.

16.
Real-world examples
The city of Gothenburg received a 2.19 MSEK grant from Vinnova to use
LoRaWAN-based sensors for measuring air and water quality.

17.
Getting your hands dirty
Wireshark
● Sigfox dissector for Wireshark (WIP)
● LoRaWAN dissector for Wireshark (Orange, docs
in French)
GNU radio
● GNU Radio scrapy for Sigfox
● Gr-lora for LoRa (LoRaWAN not yet supported)
Get your own radio module / device
Build/buy your own gateway (LoRaWAN)

18.
Learn more
https://yadom.eu/reseaux-iot/sigfox/carte-breakout-sfm10r1.html Sigfox radio module, controlled by AT
commands on 9600bps serial 24 EUR
https://www.m.nu/pycom/lopy-with-headers Microcontroller that runs python with LoRa radio module 379kr
https://github.com/int0x191f2/wireshark-sigfox
https://github.com/ltn22/LoRaWAN-Wireshark-Dissector
https://bitbucket.org/cybertools/scapy-radio/overview Sigfox Gnu Radio Companion
https://github.com/BastilleResearch/gr-lora LoRa Gnu Radio Companion
https://github.com/matthijskooijman/arduino-lmic Arduino LoRaWAN library for devices
https://www.youtube.com/watch?v=-YNMRZC6v1s Matt Knight at GRCon16
https://www.youtube.com/watch?v=NoquBA7IMNc Matt Knight at CCC
https://github.com/rpp0/gr-lora another LoRa Gnu Radio Companion, not the same as the one by Bastille

19.
Backup slides

20.
Choose the right security level for
your application
● Example: Outdoor environmental data probably doesn’t need to be kept
confidential (temperature, rainfall, air humidity, barometric pressure, etc)
● In other cases, the fact that the device is communicating at all might reveal
sensitive information
● Know what the network provides for you, and what you need to take
responsibility for

21.
Software defined radio - Sigfox

22.
Software defined radio - LoRa (1)

23.
Software defined radio
- LoRa (2)
● https://revspace.nl/DecodingLora
● Matt Knight - Reversing LoRa and his
presentation at the RSA conference
this year

24.
Cisco industrial LoRaWAN router

25.
TTN kickstarter gateway

26.
Sigfox Sweden
coverage

27.
TTN Europe gateway locations