The Adversaries Live in the Cracks

Why Systems Security Engineering Matters

Before I begin, I have one request. Please don’t shoot the messenger.

The Prelude                     

Once we get a chance to catch our breath after the recent cyber-attacks and complete our damage assessments, we will come to the conclusion that, once again, despite all of our best efforts, the “cyber adversaries” (the bad guys) continue to have the advantage over the “cyber defenders” (the good guys). There will likely be the usual “cyber sprints” to hurriedly fix things followed by calls for a cybersecurity commission or task force to figure a way out of this continuing onslaught. But if you really want to know why the cyber-attackers always seem to have the advantage in the current environment of highly complex systems and unbridled connectivity, the answer is staring us right in the face and it is very simple—the bad guys are using systems security engineering to “attack” our systems more than we are using systems security engineering to “protect” our systems. You may conclude this seems like an odd statement, but let me explain.

Complex Systems, Valuable Targets

A former Director at the National Security Agency once said “the adversary lives in the cracks” of our systems. What he meant by that statement is today’s complex systems are made up of hundreds of thousands of system components operating in a highly-connected, world-wide network. Those components can include software, firmware, and hardware as part of the “system stack”—all coupled together forming the world’s biggest and most attractive “attack surface.” The individual components each provide some type of functionality that, when combined with the other components, give the system its overall capability. That capability is used to conduct mission essential operations in public and private sector organizations across the country—including organizations that are part of the United States critical infrastructure. And, although complexity is often the price we pay for developing the needed capabilities, it is also “ground zero” for our vulnerability.

The Attacker’s View

While sophisticated, nation-state supported cyber-attackers have additional tools and means, the first job of most cyber-attackers is to obtain as much information about the system as is humanly possible—the objective being to understand the system architecture including what each component does, the interactions among components, component dependencies, and how information flows through the different components. This is the “roadmap” inside the system that dictates the path the attackers will take to be successful. Many times, attackers will exploit weaknesses or deficiencies in the individual system components (almost always commercial products) or in how those components are put together—thus, establishing a foothold in the system and then capitalizing on that initial success to execute the next steps in the attack. To accomplish this, the attackers have to be competent “systems security engineers.” By understanding what’s in the system and how the system works, the attackers can figure out clever ways to do the unexpected—including installing malicious code in otherwise trusted applications, corrupting system processes, and subverting the supply chain. They do this from a comfortable beachhead while “living in the cracks” of the system and suppliers up and down the supply chain—often going undetected for days, months, or years.

The Defender’s View

In a previous article, I made the point that compliance-based security and cyber hygiene activities alone were insufficient to protect our systems against sophisticated, nation-state adversaries. System developers employ a “strategic” and “proactive” approach to security—viewing security as a “system property” and achieving system security through the application of security design principles, development models, security architectures, and disciplined and structured systems engineering processes. Engineering involves making informed trades and decisions—which demand the application of rigorous systems analysis methods based on the cyber-physical characteristics of systems, the sophistication of the adversary, and the seriousness of the potential effect of the attack.

In the development process, systems security engineers spend a significant amount of time and effort understanding each system component and how that component operates as part of an overarching “system architecture.” The engineers look for expected and unexpected behaviors. They do “what if” analyses as the system component interactions and information flows are studied and various risks are assessed. Achieving security is an intentional by-product of the systems engineering process and not something that can be treated as an afterthought and therefore, either “added in” or “bolted on.”

Why Systems Security Engineering Matters

So, is it possible that we are continuing to be victimized by devastating cyber-attacks because we are not spending enough time “living in the cracks” of the systems we are building and engineering solutions that fundamentally reduce our susceptibility to such attacks? I don’t know the answer to that question but I think it is fair to ask. If our adversaries are spending more time in the engineering shop than we are, we cannot expect any better outcomes in the future. We are paying people to find holes in our systems and applications instead of investing in stronger, more penetration-resistant, and resilient systems and a trusted supply chain. The end result is a full employment plan for the hackers as the bloated attack surface generates a never ending supply of “zero-day” (or unknown) vulnerabilities.

The Bottom Line

In summary, systems security engineers attempt to make systems “securable” and “secure” from day zero. This attitude impacts the initial system requirements, how concepts of operation (CONOPS) are formulated, and the potential classes of solutions considered for the system. Failing to use an “engineering-driven” approach to build our systems will lead us to being more vulnerable to “zero-day” attacks. Systems security engineering gives us the tactical and strategic advantage we need. It takes time. It takes commitment. It is not easy. But if the events of this past week do not give us a serious cyber wakeup call, then we will see these types of attacks continue to escalate with consequences that are unthinkable.

And don’t forget, please don’t shoot the messenger.

A special note of thanks to Mark Winstead, Keyaan Williams, Victoria Pillitteri, and Tony Cole, long-time cybersecurity and SSE colleagues, who graciously reviewed and provided sage advice for this article.