Why we invite security researchers to hack Azure Sphere

Fighting the security battle so our customers don’t have to

IoT devices are becoming more prevalent in almost every aspect of our lives—we will rely on them in our homes, our businesses, as well as our infrastructure. In February, Microsoft announced the general availability of Azure Sphere, an integrated security solution for IoT devices and equipment. General availability means that we are ready to provide OEMs and organizations with quick and cost-effective device security at scale. However, securing those devices does not stop once we put them into the hands of our customers. It is only the start of a continual battle between the attackers and the defenders.

Building a solution that customers can trust requires investments before and after deployment by complementing up-front technical measures with ongoing practices to find and mitigate risks. In April, we highlighted Azure Sphere’s approach to risk management and why securing IoT is not a one-and-done. Products improve over time, but so do hackers, as well as their skills and tools. New security threats continue to evolve, and hackers invent new ways to attack devices. So, what does it take to stay ahead?

As a Microsoft security product team, we believe in finding and fixing vulnerabilities before the bad guys do. While Azure Sphere continuously invests in code improvements, fuzzing, and other processes of quality control, it often requires the creative mindset of an attacker to expose a potential weakness that otherwise might be missed. Better than trying to think like a hacker is working with them. This is why we operate an ongoing program of red team exercises with security researchers and the hacker community: to benefit from their unique expertise and skill set. That includes being able to test our security promise not just against yesterday’s and today’s, but against even tomorrow’s attacks on IoT devices before they become known more broadly. Our recent Azure Sphere Security Research Challenge, which concluded on August 31, is a reflection of this commitment.

Partnering with MSRC to design a unique challenge

Our goal with the three-month Azure Sphere Security Research Challenge was twofold: to drive new high-impact security research, and to validate Azure Sphere’s security promise against the best challengers in their field. To do so, we partnered with the Microsoft Security Response Center (MSRC) and invited some of the world’s best researchers and security vendors to try to break our device by using the same kinds of attacks as any malicious actor might. To make sure participants had everything they needed to be successful, we provided each researcher with a dev kit, a direct line to our OS Security Engineering Team, access to weekly office hours, and email support in addition to our publicly available operating system kernel source code.

Our goal was to focus the research on the highest impact on customer security, which is why we provided six research scenarios with additional rewards of up to 20 percent on top of the Azure Bounty (up to $40,000), as well as $100,000 for two high-priority scenarios proving the ability to execute code in Microsoft Pluton or in Secure World. We received more than 3,500 applications, which is a testament to the strong interest of the research community in securing IoT. More information on the design of the challenge and our collaboration with MSRC can be found here on their blog post.

Researchers identify high impact vulnerabilities before hackers

The quality of submissions from participants in the challenge far exceeded our expectations. Several participants helped us find multiple potentially high impact vulnerabilities in Azure Sphere. The quality is a testament to the expertise, determination, and the diligence of the participants. Over the course of the challenge, we received a total of 40 submissions, of which 30 led to improvements in our product. Sixteen were bounty-eligible; adding up to a total of $374,300 in bounties awarded. The other 10 submissions identified known areas where potential risk is specifically mitigated in another part of the system—something often referred to in the field as “by design.” The high ratio of valid submissions to total submissions speaks to the extremely high quality of the research demonstrated by the participants.

Graph showing the submission breakdown and the total amount of money eligible to be received through the bounty system.

Jewell Seay, Azure Sphere Operating System Platform Security Lead, has shared detailed information of many of the cases in three recent blog posts describing the security improvements delivered in our 20.07, 20.08, and 20.09 releases. Cisco Talos and McAfee Advanced Threat Research (ATR), in particular, found several important vulnerabilities, and one particular attack chain is highlighted in Jewell’s 20.07 blog.

While the described attack required physical access to a device and could not be executed remotely, it exposed potential weaknesses spanning both cloud and device components of our product. The attack included a potential zero-day exploit in the Linux kernel to escape root privileges. The vulnerability was reported to the Linux kernel security team, leading to a fix for the larger open source community which was shared with the Linux community. If you would like to learn more and get an inside view of the challenge from one of our research partners, we highly recommend McAfee ATR’s blog post.

What it takes to provide renewable and improving security

With Azure Sphere, we provide our customers with a robust defense based on the Seven Properties of Highly Secured Devices. One of the properties, renewable security, ensures that a device can update to a more secure state—even if it has been compromised. While this is essential, it is not sufficient on its own. An organization must be equipped with the resources, people, and processes that allow for a quick resolution before vulnerabilities impact customers. Azure Sphere customers know that they have the strong commitment of our Azure Sphere Engineering team—that our team is searching for and addressing potential vulnerabilities, even from the most recently invented attack techniques.

We take this commitment to heart, as evidenced by all the fixes that went into our 20.07, 20.08, and 20.09 releases. In less than 30 days of McAfee reporting the attack chain to us, we shipped a fix to all of our customers, without the need for them to take any action due to how Azure Sphere manages updates. Although we received a high number of submissions throughout multiple release cycles, we prioritized analyzing every single report as soon as we received it. The success of our challenge should not just be measured by the number and quality of the reports, but also by how quickly reported vulnerabilities were fixed in the product. When it came to fixing the found vulnerabilities, there was no distinction made between the ones that were proven to be exploited or the ones that were only theoretical. Attackers get creative, and hope is not part of our risk assessment or our commitment to our customers.

Our engagement with the security research community

On behalf of the entire team and our customers, we would like to thank all participants for their help in making Azure Sphere more secure! We were genuinely impressed by the quality and number of high impact vulnerabilities that they found. In addition, we would also like to thank the MSRC team for partnering with us on this challenge.

Our goal is to continue to engage with this community on behalf of our customers going forward, and we will continue to review every potential vulnerability report for Azure Sphere for eligibility under the Azure Bounty Program awards.

Our team learned a lot throughout this challenge, and we will explore and announce additional opportunities to collaborate with the security research community in the future. Protecting our platform and the devices our customers build and deploy on it is a key priority for us. Working with the best security researchers in the field, we will continue to invest in finding potential vulnerabilities before the bad guys do—so you don’t have to!

If you are interested in learning more about how Azure Sphere can help you securely unlock your next IoT innovation: