(Cross-posted from SF ISOC blog)
IoT Security Through Open Certification
The more jaded nerds who’ve been around the block a few times here in San Francisco have an understandably dismissive attitude towards the use and abuse of technological buzzwords, of which “IoT” is a contemporary offender. In one sense they’re correct in that what we’re talking about are embedded systems connected to the internet, Big Deal. But remind them that it’s a bunch of embedded systems connected to the internet in the context of security, and the salient point is sharply made. They quickly turn from dismissive to despondent, knowing where this is all likely headed.
Obligatory Scary References and Predictions
Where is it headed? You don’t have to turn to prognostication to get a glimpse of the consequences of the Earth being flooded with sloppily-developed firmware. In case you missed it, in September and October of 2016 the Mirai botnet, thousands of embedded devices comprising 36 depressingly-poorly-secured IoT products shipping with default usernames and passwords were press-ganged into “multiple major DDoS attacks in DNS services of [the] DNS service provider Dyn […] using Mirai malware installed on a large number of IoT devices, resulting in the inaccessibility of several high profile websites such as GitHub, Twitter, Reddit, Netflix, Airbnb and many others” (https://en.wikipedia.org/wiki/Mirai_(malware)). At volumes of 620-1024 Gbps, these attacks were extremely consequential and disruptive, essentially breaking the internet for many users for the better part of a day.
This attack represented the most low-hanging fruit possible; default usernames and passwords, internet-addressable devices. The sophistication required was likely minimal.
Even more recently someone set up ZMap to find raspberry pis with SSH on and the default username and password, and created a worm capable of infecting millions of hosts that probably took the author an afternoon to make.
As the number of these sorts of devices proliferate and attacks increase in sophistication, we can expect a corresponding increase in bad days for network admins, not to mention the hapless end user. The FBI in 2015 felt the need to issue a PSA to this effect: “The FBI is warning companies and the general public to be aware of IoT vulnerabilities cybercriminals could exploit.”
The danger is well-known and publicized and not worth belaboring for too long. The real question is of course: what can we do about it?
Incentives and Obstacles
The reason that many IoT products have poor security is not due to a failure of morals, bad upbringing, or stupidity, but a reasonable economic calculation on the part of the manufacturer. They are concerned primarily with the time to market. Taking extra time to design and build properly and test their code only adds delay, for which they see no fungible benefit. These products are made by thousands of large and small manufacturers and pieced together from various developers and engineers around the world, a top-down regulatory approach is impractical. There are simply too many moving parts, countries, agencies, software libraries and stacks, for effective regulations to keep pace with this fast-moving target. So what’s to be done?
In the opinion of people smarter than me, what’s needed is an open certification for things connected to the internet asserting a minimum level of security. It doesn’t need to be ultra-rigorous to be of benefit, at least at the basic level. A simple “this device is not almost certainly going to get taken over and wreak havoc” stamp would be a great first step, one that many manufacturers are not passing muster on presently.
Why a certification?
A certification process can be designed collaboratively and openly, can be implemented by anyone, doesn’t require action from policymakers, can have different levels of rigor, and most importantly provides a market-based incentive to manufacturers to not make obvious, common blunders. The result can only be greater security and stability for pretty much the entire internet-connected planet. As a user of the internet I have a personal interest in not having everything susceptible to hacks and being used to take down internet infrastructure.
There would be incentive to manufacturers to conform to the certification; consumers and institutions should prefer to purchase conforming devices vs. similar devices that haven’t been vetted. Consider a government or corporation procurement policy that mandates that conforming devices be preferred or required.
This is not a novel idea, there are in fact a small number of company-sponsored certifications already but as far as I can tell they are proprietary and run by a single company. The most promising proposal comes from the Online Trust Alliance initiative from the Internet Society. They define a set of best practices for securing IoT devices and also take into consideration notifications and privacy. Their IoT Trust Framework provides a solid assurance that a device is trustworthy to deploy, at least more than any random off-the-shelf thing.
Certification is not the only option for securing Things and embedded devices. Governmental policy is another possibility, though necessarily limited in its jurisdiction, scope, and ability to keep up with new developments in a rapidly-changing highly technical field. Also I don’t get to make policy, but I can help make a certification. As an example of useful legislation Dan Greer suggests making liability contingent on the openness of the firmware; if you use closed-source, proprietary systems then you are more legally liable for damage caused than if you used open-source software. This is both practical and reasonable, as open-source code can be audited and improved by the community, particularly if you go out of business but your devices remain. He has many more such intelligent suggestions that he lays out in his 2014 BlackHat keynote which I highly recommend watching. I also thought highly of his suggestion that devices should either be remotely-updateable (with signed updates of course) to patch flaws in the field, or they should “expire” and stop being connected to the internet after some period of time, say five years. Having insecure devices on the internet is one thing, having un-patchable systems that stay around forever is quite another. This could easily be a component of certification.
Another more extreme approach that as far as I’m aware was not predicted, is that some people such as the hacker “The Janit0r” have taken it upon themselves to release worms using similar vectors as the Mirai botnet to take over insecure IoT devices and then either brick them or firewall them so that they can’t be used maliciously. The Janit0r claims he has bricked over two million insecure devices so far, so that they can’t be press-ganged into evil servitude. The similar Hajime worm has no DDoS capability and instead blocks ports to lock down the device:
“There are some features that are noticeably missing from Hajime. It currently doesn’t have any distributed denial of service (DDoS) capabilities or any attacking code except for the propagation module. Instead, it fetches a statement from its controller and displays it on the terminal approximately every 10 minutes. The current message is:
Just a white hat, securing some systems.
Important messages will be signed like this!
To the author’s credit, once the worm is installed it does improve the security of the device. It blocks access to ports 23, 7547, 5555, and 5358, which are all ports hosting services known to be exploitable on many IoT devices. Mirai is known to target some of these ports.”
Community and Governance
Another reason for optimism is the response from assorted institutions, individuals and corporations. AWS should be praised for absolutely requiring proper (mutual TLS) authentication for anyone using their IoT platform. On June 8th, 2017 the US NTIA put out a RFC specifically about hardening IoT devices and preventing botnets. The San Francisco Bay Area Internet Society has a new IoT Working Group to promote security and best practices for development, which I’m happy to be leading. If this is a topic of interest to you, there are plenty of communities of people willing to work together to make the coming flood of Things a positive transition instead of an internet minefield.