What can attackers achieve?
LoRaWAN attacks are easy to perform over the air and over great distances due to the nature of the technology, requiring only an antenna, and their impact on the business or operations of the device owners depends on the purpose of the targeted devices.
First, attackers could trigger DoS attacks. If they have the session keys, they can send messages to the network server impersonating real devices but using message counters greater than the normal values. This forces the server to start ignoring messages from the real devices which have the correct, but lower message counter values.
Attackers could also impersonate devices by sending rogue JoinRequest messages to negotiate new session keys. This would force subsequent messages from the real devices to be ignored by the server. Impersonating the server is also possible, in which case the attackers could send rogue commands to devices to change their radio frequency (RF) synchronization settings, which would desynchronize them from the network.
Finally, attackers could impersonate devices or groups of devices to send fake data to the applications in charge of collecting the network data and acting on it. Depending on the purpose of the spoofed devices, such an action could have serious consequences.
"Imagine a LoRaWAN device measuring the pressure of a critical gas pipeline, which needs to be under constant monitoring," the researchers said. "An attacker with valid session keys could craft and send LoRaWAN messages with normal behavior data for the pipeline pressure, masking any anomaly and hiding a physical attack against this pipeline. If not caught in time, such an attack could lead to an environmental, economic, or, in a worst-case scenario, lethal disaster."
LoRaWAN devices include smart energy meters deployed by utilities; sensors for monitoring CO2 levels, temperature, pressure and leakage in industrial facilities; sensors for street lighting, smart waste management, gunshot detection, public transportation signs, flood and seismic monitoring in residential areas; alarms, smart locks, smoke detectors in homes; smart irrigation systems; and much more.
A need for LoRaWAN auditing and monitoring tools
Because the LoRaWAN protocol uses encryption and is advertised as a secure protocol, users and developers have quickly embraced it and its popularity is expected to grow because it also offers other benefits such as lower cost and easy installation and maintenance. However, through their new paper, the IOActive researchers want to highlight that many such networks are exposed to security risks and should be audited and monitored for weaknesses and attacks.
"When we started this investigation, we found out that there were no tools available for testing LoRaWAN networks," Cesar Cerrudo, CTO of IOActive, tells CSO. "So, we built our own tools and are releasing this new framework that's very useful because it allows you to capture the traffic, analyze it, try to crack the keys, inject fake data, and more. An auditor can use these tools to assess the security of a LoRaWAN network."
There are also no tools for protecting such networks, so people running them are completely blind, Cerrudo says. "They can't know if someone is trying to hack their networks or has already hacked their networks."
Fortunately, some attacks do leave traces and IOActive's open-source LoRaWAN Auditing Framework (LAF) can be used to discover existing compromises. It won't help block new attacks, but it can serve as a passive detection tool. For example, it can be used to set up checks for duplicate messages or for messages counters that are lower than expected, which could be signs of device spoofing.
The use of devices with hard-coded session keys should be avoided because they're at greater risk of being compromised. These are known as activation-by-personalization (ABP) devices and LAF can be used to discover them so they can be flagged for replacement. The framework can also be used to uncover weak keys so they can be regenerated and replaced. IOActive's paper includes recommendations on how to protect keys, including using devices with hardware secure elements (SE) and servers with hardware security modules (HSMs).
"The best approach to preventing attacks is holistic, where the complete LoRaWAN ecosystem is secured," the researchers said. "This can only be achieved if all of the technology that is part of the ecosystem (devices, gateways, network servers, join servers, application servers, and applications) is properly security audited. This way, possible security problems are identified and fixed. This should be done at least twice a year, as the ecosystem is not static. LoRaWAN networks are very dynamic with new components being added regularly."