|
Smart Grid networks are increasingly connected to the Internet and need to have their components as well as perimeter defenses tested for security readiness on an ongoing basis. As a best practice, IP networks typically have multiple layers of perimeter defenses to keep improper traffic out while allowing valid traffic through. In fact, Smart Grid devices often have integrated packet-filtering DPI firewalls that are not signature-based.
Sophisticated firewalls or intrusion prevention devices incorporate signature-matching engines to identify and filter out traffic corresponding to known attacks. It is insufficient to simply load the signatures and presume they are effective day one or anytime in the future. The Smart Grid is too important and service outages due to network elements being unprotected are practically negligent and must be avoided.
Electric-power customers understand if power goes out due to a thunderstorm, but would be much less forgiving if the power went out due to the actions of a hacker exploiting a well-known vulnerability. For maximum vigilance, a best practice is also to test for unknown weaknesses in services by fuzzing, a process that statefully interacts with a target to deliver invalid or unexpected inputs that are carefully crafted to expose programming errors that frequently appear in protocol implementations. Fuzzing based on an accurate model of the service is able to expose weaknesses within the actual protocol implementations, not on the requirements documented within the standards.
Fuzzing is challenging for traditional test vendors that must wait for the standards to settle enough before beginning to create test cases for that protocol, but these test cases are based on what the standards body says is supposed to happen, not on what the vendors actually built. Certain important protocols are entirely proprietary, and test vendors are unlikely to ever gain access to these protocol specifications, resulting in 0% test coverage for this protocol. Just because it’s proprietary doesn’t mean there aren’t any bugs in the implementation! These protocols are just as important to test as any other.
An important application of fuzzing is being used by Mu's industrial control system and smart grid customers today when they are selecting new vendor equipment
for use in their future network planning. They deem it critical that
all equipment must meet an established security baseline, especially
around interoperability and robustness of the protocols they intend to
use within their networks, especially since their missions are often
critical to the operation of the local or national economy.
One of the best ways to
accomplish this is via fuzzing, either based on open protocol
specifications or on service-specific traffic flows that must be
supported by the government agency's network. Mu's Protocol Fuzzing and Studio Zx modules
make it easy to compare the results of many different target devices to
see which is best able to stand up to invalid or unexpected inputs
around the traffic that the network must support. A network that is
constantly subjected to fuzz testing, throughout the deployment life
cycle, starting from the earliest phases of vendor selection, is going
to experience fewer "surprises" during critical operational conditions. Studio Zx has the unique ability to perform fuzz testing even for proprietary protocols that are so common in this market segment.
To test proprietary protocols (or aspects of protocols) and to deliver test solutions ahead of standards, it’s essential to consider a new scheme for fuzzing, based on accurate models of the service, which provides extremely fine-grained and guaranteed-relevant test cases that will expose many weaknesses before they ever appear in a production Smart Grid network. So, if the power or utility delivered IP service goes out, it won’t be because of the Smart Grid….
|
