10/15/2019
10:00 AM
Marc Laliberte
Marc Laliberte
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Why Bricking Vulnerable IoT Devices Comes with Unintended Consequences

Infosec vigilantism can cause serious harm in the era of industrial IoT and connected medical devices.



For several years now, security experts have been trying to bring attention to the growing threat that insecure Internet of Things (IoT) devices pose to networks around the world. The enormous growth in popular connected devices like webcams, DVRs, and smart watches has made it possible for hackers to amass huge botnets that can launch devastating distributed denial-of-service (DDoS) attacks.

Unfortunately, some vigilante hackers have tried to solve this problem with "bricker" malware that infects and destroys insecure IoT devices before they can become part of a botnet. This might seem like a positive on the surface, but this tactic creates serious, sometimes life-threatening risks as more IoT devices are used in industrial networks and healthcare organizations.

Let's start at the beginning. IoT security became a top-of-mind issue in late 2016 thanks to the record-breaking DDoS attacks by the Mirai botnet and its subsequent source code release. In a perfect world, this should have been the wake-up call to improve IoT security. Unfortunately, slim profit margins and rapid development times kept IoT security considerations on the back burner and led some individuals to take matters into their own hands. The first instance of IoT vigilantism was in 2017 when a strain of malware known as BrickerBot began making its rounds.

Similar to the Mirai botnet, BrickerBot exploited flaws like insecure, hard-coded passphrases to log in to vulnerable IoT devices. But once it connected to a device, it didn't add it to a massive botnet. Instead, it deleted files, corrupted the system storage, and disconnected the device from the Internet, effectively making it unusable. While it is possible to restore the device to factory defaults, the average IoT user likely doesn't have the technical skills to do this. The author of BrickerBot, known by the pseudonym Janit0r, explained in an interview that his malware was intended to prevent devices from being infected by Mirai. Janit0r believed that if IoT manufacturers and owners weren't going to take security seriously, then the devices shouldn't exist to begin with.

In the end, BrickerBot destroyed over 10 million devices in just nine months before Janit0r retired it from service. While that may sound like a lot, it's still less than one-tenth of 1% of the estimated 14 billion IoT devices online worldwide.

But the end of BrickerBot wasn't the end of IoT bricking malware. In early 2019, a new variant of IoT bricking malware called Silex began infecting devices worldwide. Within a few hours, Silex had infected thousands of devices, deleting system file and firewall rules, and effectively rendering them useless. With the Mirai source code public, it's not a stretch to think there are other similar malware variants lurking undiscovered in the wild today. Thankfully, individual IoT owners can also protect themselves from both botnets and brickers by changing the default passwords on their IoT devices, not exposing the telnet port (which BrickerBot uses to infect devices) and performing basic network segmentation and monitoring.

Bricker malware is dangerous because it doesn't discriminate between different types of IoT devices. Almost every industry is incorporating IoT technology in some way. "Smart city" technology is becoming widely adopted across the globe, with municipalities connecting everything from power grids to traffic lights to networks. Healthcare is another sector that's quickly adopting IoT technology, with the Internet of Medical Things projected to reach $136.8 billion worldwide by 2021. While some might question the need for refrigerators to connect to the Internet, there is no arguing that the ability to quickly share data from an ECG/EKG machine could be the difference between life and death. As widespread IoT adoption continues to grow within these sectors and overall, bricking malware can have some devastating consequences.

The problem is that many of these new IoT applications exhibit the same security lapses as consumer IoT devices, but with significantly higher risks if they fail. A rash of bricked industrial IoT sensors could cause widespread power outages, and an infusion pump or medical monitor that unexpectedly shuts off could put patients' lives at risk. The authors of BrickerBot and Silex might not have been so ready to claim their work was for the good of the Internet if they truly considered the serious collateral damage that they might cause along the way.

There are other options to improve IoT security that don't involve such a high degree of risk. Security researchers can work on raising awareness about connected device security, participating in public education initiatives and trying to drum up consumer demand for secure devices. Just last year the state of California, the fifth-largest economy in the world by GDP compared with other sovereign nations, passed Senate Bill 327, which mandates that manufacturers of connected devices equip their products with reasonable security features by January 2020. While the bill will have little effect on the masses of inexpensive IoT devices imported from foreign countries every year, it's a step in the right direction that can be built upon with future legislation.

There is no denying the IoT industry needs to fundamentally change its approach to security, but vigilantism is not the answer. There are less destructive ways to convince both manufacturers and consumers that developing and deploying secure devices is worth the investment.

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Marc Laliberte is a senior security analyst at WatchGuard Technologies. Specializing in networking security protocols and Internet of Things technologies, Marc's day-to-day responsibilities include researching and reporting on the latest information security threats and ... View Full Bio
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