We read daily about security breaches of our corporate computers, our home
computers, as well as many government computers. Even though these systems may
have varying levels of security, they still experience unauthorized access on
a routine basis. This problem will assuredly become a real threat for embedded
systems as they become a more integral part of our network-centric infrastructure.
As we move more and more into the net-centric world, embedded devices will become
a key portal into our Information Technology infrastructure. The embedded systems
of tomorrow will need to have an operating system that will assure security. This
will prove true for our military infrastructure as well as our commercial systems.
We secure our systems today in the form of login passwords and data encryption,
but that is not enough. Clearly, the security available today is not robust enough.
The main reason for the current level of security breaches is that there is a
lack of “security-in-depth.”
We protect access at the upper levels, but not much below the application layer.
Let’s face it. If the operating system itself can be hacked into, then the
application above it can only be as secure as the operating system it is running
on. For embedded systems, there is a real need to deploy systems that are indeed
secure.
The Department of Defense (DoD) is taking embedded system security seriously.
The U.S. military is moving rapidly to the “Net-Centric” warfare model.
From the soldier in the battlefield to the General back at headquarters, everything
and everyone will be connected together in a worldwide network. These systems
will track troop movements, provide targeting information, issue battle orders,
transmit top-secret information and even order meals for the troops. Given the
vast range of information that these systems will be handling, they will need
the capability to carry multiple levels of secure transmissions, from unclassified
to top secret.
The Department of Defense and the NSA are driving the adoption of secure embedded
systems. DoD Directive 8500.1 establishes a policy to achieve information assurance
(IA) through the “defense-in-depth” approach that integrates the capabilities
of personnel, operations and technology, and supports the evolution to network-centric
warfare.
Due to this and other mandates, the DoD is pushing very rapidly to get the latest
major military programs to move to embedded operating systems that meet certain
levels of security as defined by the Common Criteria. Common Criteria defines
seven different security levels called Evaluated Assurance Levels (EAL), ranging
from one to seven, with one being the lowest level and seven being the highest
level. While Common Criteria does not require the use of EALs, it is generally
accepted as the best means for defining the security level of OSs. EAL-7 is equivalent
to security Level A in the DoD Orange Book, the highest level of security for
government systems.
Embedded software products used in these secure products have their entire
systems evaluated for security. This system evaluation, however, is extremely
costly. As a result, in many instances the OS is allowed to run and work in
concert with other systems in what is referred to as “system high mode,”
where security and information assurance responsibility is offloaded across
several OSs to create a high security environment (Figure 1). This usually requires
multiple sets of hardware in order to keep security separation. Designers are
driving toward the goal of achieving Multiple Independent Levels of Security
(MILS) on one set of hardware and a single operating system (Figure 2).
This movement is prevalent in the DoD, and companies in the private sector are
starting to be held to the same security standards as U.S. Government agencies.
For example, ISPs, financial institutions and power companies are being forced
to evaluate their OSs and products that are part of the country’s critical
security infrastructure. Recent virus attacks have demonstrated that there is
a significant need for secure OSs that cannot be hacked or compromised. Security
breaches costs hundreds of millions, if not billions of dollars.
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