Note: This research was presented at Black Hat 2018.
The Internet continues to evolve and expand at an astonishing rate. Our constant desire to remain connected or feel some sentiment of connection seems to be a high priority for individuals. But, cellular connectivity does not stop at consumers on a personal cell phone. The demand for constant connection extends into servicing nearly every industry that needs long-range, constant connectivity. This requirement is especially true of organizations that operate fleet vehicles, as innocuous as a delivery driver, or as critical as a police car.
Hollywood has provided a spectacular number of films depicting hackers involved in crime rings such as Lyle, the character portrayed by Seth Green in the Italian Job. At the end of the film, Lyle leverages his skills and talents to look after the health and welfare of his associates by manipulating traffic signals to control the flow of traffic, which subsequently assists in their successful heist.
This scene is no longer fantasy. For instance, the traffic lights that are referenced do exist. They are often connected back to a smart city’s infrastructure through the use of VPN tunnels and other private means of communication over devices like cellular gateways. These gateways are similar to the modems and routers used by consumers at home but with an additional feature, cellular connectivity, often in the form of 4G/LTE, if available. Additionally, these devices are capable of providing a variety of connection options, including wireless connectivity over 802.11x, Ethernet, USB, serial; analog and digital I/O; and cellular bands ranging from 2G through 4G LTE. If said devices are not configured properly, an attacker may be able to access them and do just as Lyle did in the Italian Job.
It feels like a time warp, but as with all cyber threats, they do not appear instantly. They evolve slowly in the background over long periods of time until the problem seems to reach a critical mass. Many threats grow over the course of months and years before anyone notices—if they notice at all. It is highly likely that if a threat actor has laid eyes on a target and decided to begin attacking, discovering the attack (let alone thwarting it) could be a real headache, given the lack of visibility into the what, who, where, and when in logging activity.
Critical emergency services such as police, fire, and medical manage their fleets with vulnerable cellular IoT devices. “Vulnerable” doesn’t have to mean a vulnerability within the hardware or software, although we suspect that is the case in some makes and models, we just haven’t tested every model or manufacturer uncovered. In this instance, we are talking about devices susceptible to remote attacks because of their weak access control and use of default credentials. Once accessed, an attacker can use the device to launch attacks, as we have seen with thingbots like Mirai and Reaper, or they can use that access for nefarious purposes to spy, redirect commands in the case of a fleet taking orders from a remote command, or shut the system off, effectively disabling operations. Because the critical emergency services we depend upon are using these systems, this is an urgent human-interest matter as we have moved beyond the unpleasant life impact of stolen data, and into attacks that can literally cost people their lives.
Nearly two years have passed since we first started observing cellular gateways distributing packets across the internet. Today, we are only scratching the surface of what will inevitably turn into years of future research and discoveries before the world has tackled the problem of IoT devices being deployed without security considerations. For now, this article includes the following, and will be followed up with future research and discoveries.
- The existence of cellular IoT devices that are not properly configured is allowing attackers to easily leverage remote administration for nefarious purposes.
- The improperly configured devices we discovered and tested had either default administration credentials (such as admin:12345), or they required no authentication at all.
- The absence of logging capabilities on these devices ensures that nefarious activities cannot be tracked.
- Because most of the use cases for cellular IoT are for moving fleets, devices that need tracking, or remote critical infrastructure, virtually all of them have GPS coordinates. Excessive information disclosure, such as providing GPS coordinates publicly without requiring authentication (as some devices we discovered do) is giving attackers the ability to track fleet vehicles without ever breaking the law with unauthorized access. Yes, police cars can be tracked without breaking the law.
- There is no bias on which industries or cellular device manufacturer will fall victim to threats emerging from cellular devices. Virtually every industry that requires some form of long-range, constant connectivity is impacted (and likely, most manufacturers) as development standards apply unilaterally.
- As of July 28, 2018, we have identified more than 100,000 devices that are impacted online. 86% of the devices identified exist within the United States.
- Attackers have been exploiting many of these systems since August 2016, if not earlier.
- We have a defined list of impacted Sierra Wireless makes and models, however, we believe the problem to be widespread across all manufacturers of cellular IoT devices.
Discovering anything new is often an accident; we stumble or trip and fall into a finding that wasn’t the initial intent, as was the case for this research. This research unintentionally began while looking into Bashlite.1 The Bashlite research just so happened to coincide with the Mirai attack on DynDNS. While looking into the Bashlite incident, we stumbled upon a device we originally thought was a DVR infected by Bashlite. Looking further, we identified it as a digital signage device responsible for displaying flight arrival and departure times at a major airport in Europe. The system was actively compromised, which we disclosed to the impacted party. That party shipped the infected drives to us, which ultimately served as ground zero for this body of research. During the Bashlite incident, we were wondering how big the problem might be, so we began scanning. First manually on October 22, 2016, and then using a more automated approach starting on October 24, 2016. Part of that scanning effort included the airport network impacted by the Bashlite incident as they gave us authorization to do so. Those scans revealed cellular gateways manufactured by Sierra Wireless, including one within the airport network that was publicly accessible.
Initially we used Shodan to get an estimate of how many Sierra Wireless gateways exist on the Internet, and it gave us a preview of what we anticipated: a lengthy list of hostnames and IP addresses to research further. Sierra itself describes how vast and deep its reach is within the IOT and industrial system space—the industrial controls that are often threat-modeled to not include connectivity to the Internet. They are often highly disparate networks of devices that do not “speak IP” like packet switching networks do.
What did we find?
In October of 2016 we identified 49,962 hosts that appeared to be vulnerable to weak authentication in use by Sierra devices. The vast majority of these devices were located within the United States (84%), and therefore the US became our initial focus. The map in Figure 1 shows the GPS coordinates of the public-facing static IP addresses of devices discovered in the US in October 2016.
We continued scanning from October 24, 2016 through July 30, 2018. Each scan became more precise as we tuned our scans connecting the dots between the affected models and software versions through SSL certificates, hashes of image assets in use on Sierra’s configuration GUI, and copyright references in their footer.
In September 2017, we discovered 58,670 hosts. During this time we were also attempting to tune our scans through fingerprinting devices. This effort proved difficult because the devices would often disappear.
In July 2018, we discovered 105,400 hosts, as shown in Figure 2. This figure also compares Shodan results (the search engine we initially started with to discover devices), with scan data from our partner Loryka, because they were able to find a significantly larger number of devices than Shodan. Despite the larger numbers, the spread of devices across networks remained steady with approximately 70% of devices living on Verizon’s network.