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IoT: What is Least Privilege?

Can you say with certainty that none of your network devices have ever been pulled into a botnet army? If you don’t operate under the principal of least privilege, it’s likely that you can’t. This article will provide an overview of what least privilege means, and how it can help to relieve your IoT security headache.

What is Least Privilege?

Least privilege is not a new concept and any organization can adopt it. It’s simple: restrict the access of every user, device, program, etc. to only the minimum information and resources required to carry out its designated function.

For example, you may restrict the typical user from installing new software at their workstation beyond what the organization provides them to perform their tasks. Or a department may not be able to access the files and directories used by a different department. Basically, if they don’t need it, why give it to them?

As far as prevention goes, the benefits of least privilege in mitigating insider threats are clear. Because insider threats by their nature originate within your perimeter security, restricting access restricts damage. But what about external threats?

Least Privilege and the Internet of Things

While the IoT market booms, security professionals are biting their fingernails. So many vulnerable internet-connected devices exist, often due simply to a lack of diligence on the part of the manufacturer. All sorts of objects, from baby monitors to cars, have proven vulnerable to compromise. The security threat has become such a prominent concern that the Senate has deliberated whether to pass legislation on it.

According to an article by Dr. Phillip Hallam-Baker, however, part of the problem is that the code and operating systems of many IoT devices are needlessly complex. He says, “the more complex a system is, the harder it is to test, and the more likely it is that it will go wrong.” Furthermore, operating systems like Windows and Linux—which are cheap and fast to use in the development of IoT devices—suffer a large attack surface because their purpose is to be as flexible as possible.

This is where least privilege comes in. You don’t need your smart thermostat to be able to communicate with all of your systems; it just needs to regulate the darn temperature. Minimize the attack surface of single-function devices by only allowing them the resources needed for that one function.

Least Privilege and Network Traffic Analysis

Unfortunately, rules get broken. Even when you operate under least privilege, how do you know whether the everyone and everything is following the rules?

With a proper network traffic analysis system in place, it’s actually quite easy. If you know the single thing a device should be communicating with, it’s a red flag when you see traffic between any other source. Then you can begin to investigate the issue.

To try it out for yourself, check out the free trial of our network traffic analysis system.