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InfoQ Homepage Podcasts Security Requires Traveling the Unhappy Path - a Conversation with Robert Hurlbut

Security Requires Traveling the Unhappy Path - a Conversation with Robert Hurlbut

In this podcast Michael Stiefel spoke to Robert Hurlbut about what it means to make an application, not just the code, secure. Robert is a Principal Application Security Architect and Threat Modeling Lead at Aquia, a PhD student at Cap TechU and co-host of the Application Security Podcast.

Key Takeaways

  • Most developers think in terms of tactical security (e.g. avoiding SQL Injection attacks). To build secure applications you have to think in terms of strategic security which involves threat modeling. This analysis does not organically emerge out of the development process.
  • Since security tradeoffs revolve around risk management, architects have to be able to communicate effectively.  They have to be able to talk about technology to the business people, and business to the technologists.
  • Security, like other "ilities" is not something that can be simply written in a use case.
  • Security revolves around making applications resilient, which means understanding how to recover, and keep your application state and data consistent after a failure. You have to think about the unhappy path - what happens if something goes wrong.
  • You must understand what the end user needs to do to get their job done.

Introduction [00:50]

Michael Stiefel: Welcome to the Architects Podcast where we discuss what it means to be an architect and how architects actually do their job. Today's guest is Robert Hurlbut, who is a Principal Application Security Architect and Threat Modeling Lead at Aquia, a PhD student at Cap TechU and co-host of the Application Security Podcast. It's great to have you here on the podcast. I'd like to start out by asking you, were you trained as an architect? How did you become an architect? It's not something you decided one morning, you woke up, got out of bed and said, "Today, I'm going to be an architect."

How I Became a Security Architect [01:29]

Robert Hurlbut: Interesting story. No, I wasn't trained directly as an architect. It wasn't something that when I went to school many, many years ago that I took a track to be an architect. Instead, for many years I was a software developer and my background originally was mathematics and physics. But when I graduated, even while I was in school, I was doing some software development. I had a minor in computer science as well, but as I graduated, I had opportunity to go into the software field to do some application development, and I took it. That's where I stayed for many years, focused on building applications. So that's where I started in terms of then learning about software architecture.

I can remember in particular being a part of a couple of engagements. There was a point in time where I started to convert towards being a consultant or contractor really, more than anything else, opportunities to work on lots of different projects, lots of different companies. But being a part of one in particular, I remember someone saying, I'm an architect, and I thought that was a really interesting profession, what they were doing. They did a little bit of coding, but mostly they were designing the system that we were building. They would draw some diagrams and share it with us and they would talk about some decisions that needed to be made.

As I saw what this person was doing, I thought, "Well, that's a really interesting role to consider in the future. How would I do that myself? How would I get to a place where I could then maybe say I'm an architect or I'm filling that role?" That's my beginning, introduction to it, not in school, but just through work experiences and seeing others who said they're architects.

Michael Stiefel: That's interesting, you took what many people consider to be the traditional path, developer then architect. I would argue that actually there are people who are good at development, there are people who are good at architecture and there are skill sets that are different for different people, and one is not better than the other. Of course, sometimes the architect is also a developer and sometimes the developer does a little architecture. How do you feel about that?

Robert Hurlbut: Yes, great question. Over time I would see different styles, as you mentioned. There would be opportunities to work in an environment or on a team where there is an architect or what you might call a chief architect, that was completely a business role. They did not code at all. They many, many years left that. Now, all they were doing was facilitating, helping other architects on the team who also were just focused on building out system architectures and evaluating some of the work and so forth and interacting with the business. Then, there were others that were more focused on a mixture of the two, developer architects is what we call them, where they definitely did a lot of coding.

But they were also taking some time to draw diagrams on a whiteboard, bring the team together, talk about decisions on the design. For myself, actually, I gravitated towards that role more than anything else, was for many, many years more of a developer architect. I think there are, there are many different flavors and perspectives. I think they're all needed. There is that someone who can see the big picture and keep us on track. Then, there are others who as a developer architect could already understand the code, already understand the platforms and the various advantages and disadvantages and so forth and can make some recommendations.

But also, because they understand the platform, can make some recommendations on system design, on the tools that are being used and so forth. I think all of those are needed, and I don't see one better than another.

Understanding the Business Is the Foundation for Architecture [06:04]

Michael Stiefel: But thinking about what you just said, it seems to me that there are two things that all those kinds of architects need. One is they do have to understand the business to some extent or another, so that they have to be able to talk technology to the business people and business to the technology. Because one of the things that I've discovered over the years is that what looks easy on the outside can be hard actually to implement. Then, conversely, what looks hard to implement can be easy. Someone has to explain to the business people, this is a great idea, but it's going to take a lot of work even though... It's easy to write English language statements, but computers don't understand English language statements, so that can be very difficult to do.

The other thing is that there are certain things that can't be written to a use case. Security, which is your area of expertise we'll get to, you can't write a use case that says, make the system secure. Or, scalability, or responsiveness, or all these kinds of what we like to call the ilities, can't be written into a use case and therefore have to be the responsibility if not to implement, but at least to be responsible for it. Because in my experience, if no one's responsible for it or if everybody's responsible for it, it never gets done.

Robert Hurlbut: Correct, yes.

Michael Stiefel: Do you have any opinion about that?

Robert Hurlbut: Absolutely. I agree a hundred percent that for myself and many architects, business is actually one of the most important things to realize, is that we're working with a business. We need to understand the business goals. We need to understand the business priorities. That does impact influence, help us navigate what we're doing, where we're going. It helps us ask the questions, why are we doing what we're doing and as well as how, but why? Why here? Why now? Why is that a goal? Why is that and how does that reflect, or will be reflected into the work that I'm doing, and our team is doing and so forth? Absolutely, you got to understand the business, and that means also communication.

Another aspect of an architect is that communication with your teams, but also with the business. Being able to translate those requirements, being able to translate those goals into, as you mentioned, the use case. If I build a use case, that doesn't mean anything if I can't understand it, if I can't translate it into something that a business person understands, as well as development team understands, that can turn into a reality. That's an important aspect as well for an architect.

Michael Stiefel: Around those lines, before we get into security directly, because that's clearly one of those things that you can't write a use case for. Some people argue that we don't have to think about architecture, that sometimes architecture magically emerges out of the development process. As a security architect and a threat modeler, do you have an opinion about that? Is there certain circumstances where that's true and others where it's not?

Securing the Network Is Not Securing the Application [09:14]

Robert Hurlbut: Yes, I do. I do. In fact, if I can give a little bit of background, I did switch or start to switch more and more towards security architecture about 20 years ago when I really just learned about application security. I already understood that network security was a thing. We already talked about firewalls, we talked about ways to protect the network.

Michael Stiefel: Incidentally, if I might just interject for a second, that's a good example of something you can't write in a use case. Firewalls don't appear in use cases. Networks don't necessarily appear in use cases.

Robert Hurlbut: Very true, very true. But I also noticed, and others did as well in the industry, we didn't really talk a lot about the software itself and the security requirements around the software. It was more or less thought that the network and any firewall rules and things like that you might put in place, that's going to take care of us, that's going to protect us from the outside. But of course, what we do is we open ports, web pages, at least way back when we're mostly on port 80, which is completely wide open, with data being set and so forth. But in terms of emergent architectures just from development, and do we need architects or not, and I know you have a very famous talk, we don't need no stinking architects or something like that, if I remember correctly.

Michael Stiefel: Yes, yes.

Software Security Must Be Actively Pursued [10:38]

Robert Hurlbut: But especially within security, the idea that I will somehow fall into being secure, that as I develop and I develop and I develop, I will just somehow or another be secure. That goes back to that whole idea of relying on the network, relying on the perimeter for you so that you don't have to think about these things. But reality is on the software side, there are decisions that you make. There are opportunities if you do not think ahead of how you're developing your software that can lead you or leave you open with vulnerabilities, leave you open to potential attacks and compromise. As a result, you do have to step back and think about the design and think about being intentional with how you're putting things together. That's where architecture comes in.

Michael Stiefel: Actually, I would divide those things into two categories. There's one category that says avoid a SQL injection attack. Those are sort of, tactical, developers can do them. How do you make sure that you hash passwords and all that stuff that is tactical security.  Very often when you see people who talk about security, especially to developers, it's this tactical security, but you are actually speaking at a much higher level of architectural security, system security, which does not fit into a tactical approach. But you actually need someone looking at the whole picture and deciding that, "Well, yes, this may make sense if you just consider the technology. But if you actually look at the way the real world works, that isn't going to fly."

This might be a good segue into what you see as these important issues in security. What is it that people who are developers need to understand? What are these things that architects need to understand, and what do you see as the major problems in security? I guess I put three big topics together in one, so you can answer them in any order that you want.

Robert Hurlbut: Okay, sure. Well, from a developer's perspective, you're right. There's a lot of tactical recommendations to help a system be secure and to write what we call secure code. Meaning that you're still thinking, developers thinking ahead about... Let's just take SQL injection. How do I deal with that? Typically, as recommended, we use parameterized queries. That means if we take input from a user, we're not just taking it as is, as a string and then sending it directly to the database or concatenating strings and sending that as a command to a database. That opens you up to a SQL injection attack. Instead, we recommend, as a tactical measure, to use parameterized queries, which is instead of concatenating strings and just taking whatever the user input is, instead to use parameterized queries.

That just simply means that we take those statements as essentially, if it's a string, we recognize it as a string parameter. Then, it gets sent to the database, not as a command but just simply data. It doesn't get executed, and that's the key thing. We don't want data to be executed as commands, instead of we want them as simply what they are, they're parameters into a statement to the database to retrieve data and so forth. We give that kind of guidance. Developers have to think ahead when they're writing out their code. This is the safe way to write code or the secure way to write code. That comes into play. For architects, there are some other things to think about. Larger things, if you will, in terms of approaches and common issues.

Authentication, authorization, that's a particular set of things for identity and access management that can get completely wrong. Some will say, "Well, I've authenticated, and to me that's the same as authorization." I've identified who you are, but have I really determined what you can do? Authorization. Well, maybe not, and you can get that confused. You can get them out of order and so on. Those are some things in terms of a design approach, and thinking about how you build out your architecture to accommodate cryptography is another one. Really a big one. Certainly don't roll your own. That's what we always recommend. It takes years and years.

Michael Stiefel: Don't build your own car.

Robert Hurlbut: Don't build your own car. It takes years to get really good algorithms, I'm sorry, encryption algorithms and so forth to be able to, or hashing algorithms, to be able to do what we need to do for cryptography. You evaluate, what are the best ones out there? There's lots and lots of testing.

Michael Stiefel: There's decades of experience and testing.

Robert Hurlbut: Experience and testing, and it changes over years. One time, SHA-1, then SHA-2. Then, of course, MD5 is a long time ago for hashing. You definitely don't want to do that, but you need to also keep up-to-date. Those are what architects need to do as well. Keep up-to-date with some of those kinds of advancements in terms of how are we making sure that we're using the best algorithms and the best techniques to be able to store data and prevent it from being captured by others who shouldn't have access. Those are some things that architects need to think about and continually evaluate and help them with their designs. There was a third one you mentioned. I forgot-

Michael Stiefel: Well, before we get to the third one, authorization to me is a particularly interesting example because you have to authorize and know how to authorize in different parts of the application. Because I could be doing something and trying to, depending on my credentials, I may or may not be allowed to run this report or see certain columns in a report. When you think about, I once had to tackle that issue, you may be able to run a report but can't see certain columns out of the database, that could get quite sophisticated to do. There are other examples of this. These are things that developers may or may not know how to do or to deal with the security infrastructure, and how to do this.

This is a good example, I think, and you can tell me whether I'm right or wrong, of where there's a play between the security architect and the application developer that the application developer may not be aware of.

Threat Modeling [17:20]

Robert Hurlbut: Yes, agree. Agree. That's been my focus and why I have focused on over many years looking more and more at threat modeling. Threat model is a way of looking at a system, analyzing, typically a representation of a system, which means it could be description of the system, of what you're doing. It could be a diagram that helps you understand what's going on in the system. But essentially, trying to evaluate any particular security or privacy issues within that system that have some impact or could potentially have some impact on that application. Of course, it can impact your performance, other things as well, but especially the security, the integrity of that system.

Michael Stiefel: That's an interesting point you just raised about how it impacts the performance, which again, shows why you need this, this is something that comes in the purview of an architect. Because somebody who writes something that's performant just from a code point of view and doesn't take... To encrypt or decrypt takes time. For example, if lots of packets are coming in and you have to encrypt or decrypt each one of them, either because they're signed or they're encrypted, that's a performance impact and that has to be taken into consideration when you're writing your algorithm or making your promises of what your uptime is or whatever it is. Those are examples of cross-cutting concerns that are just not a development issue.

Resiliency [18:45]

Robert Hurlbut: Yes, absolutely. Another common issue is denial of service attacks. How am I building my system to be resilient towards those types of attacks? Attacks could be, a denial of service attack could be external, but also could be internal. External, we like to think, well, I have a bunch of bots and maybe it's a distributed denial of service attack where you have bots everywhere on machines that are trying to call services, trying to upload large files that you don't expect put in. I've seen 200 character passwords into a form and just do that repeatedly for trying to log in and take your authentication system down if you can.

I've seen those kinds of things and that's what we think of. But the other kind is internal, where services I rely on, databases, other APIs, external APIs that I rely on. Other things that I'm trying to-

Michael Stiefel: Credit card agencies.

Robert Hurlbut: Credit card agencies, exactly. Yes, how do I build that in for resiliency? Airlines are notorious for, and different companies that sell books and other kind of resources, are notorious for this where they figured out, do I just sit there and wait for the billing to happen? No, you take the order and then you go do the billing later, and then you verify that the credit card worked, and then you come back, and those kinds of things.

Michael Stiefel: Also, the business enters in there because it depends on, well, is this a million dollar order or order for five cents? The five cents, you might decide in the business case, let them have the order, 99% of the time people are honest. If it turns out to be dishonest, I've only lost five cents. On the other hand, if it's a 10 million order coming from a company you've never heard of before, then that's a different story. Again, these things are not cut and dried, and this requires interaction between the developer, the architect, the business. These are not simple things.

Security As a Business Requirement [20:47]

Robert Hurlbut: Absolutely. Yes, the business was the third. The business understanding that security is a business issue, we're seeing that more and more these days. There was a time where security was thought to be a nice add-on or sort of, we'll get to it when we get to it, but we're in a hurry now to get this shipped out. In version two, maybe we'll think about more security type of thing. You can't do that anymore. It's a first world citizen for most organizations now, it has to be. There are customers who rely on the security of organizations. How is my data stored? Are you protecting that data? What about financial transactions, are you protecting those? If you lose a lot of money, do I lose a lot of money as a customer? Those kinds of things.

We already talk about the business goals of performance and some resiliency, but it also relates to security as well. Security is a first world citizen as well in all the other things that we're thinking about now, and it has to be for many organizations that it can't be a byproduct. It can't be an afterthought. That's another aspect as well to think about.

Michael Stiefel: You were talking a little bit before about threat modeling, and that also raises the question now, what do you see as the key issues in security that developers need to be sensitive to, architects need to know, things that companies neglect or don't think about? If you want to encompass that in threat modeling or whatever you see to be the appropriate way to raise that issue, just go ahead.

Looking at the Big Picture [22:34]

Robert Hurlbut: Well, yes, and I appreciate the callback to threat modeling. Where I was going with that earlier is that that's a good way to communicate the concerns, security concerns to teams. Developers understand a bit about the bigger picture when they see a threat model of a system. They're understanding that this is not just a particular place and code, but on the bigger picture, how do these various components interact, how these various systems interact, and what does that mean in terms of transferring data, saving data, moving data, authenticating against the data that's being sent and so forth for the data that's being sent. That's where a threat model can help.

For architects, threat models, again, help them determine and understand requirements. A developer would like to see requirements, would like to see, here's what I need to build. A threat model can help an architect think about those security requirements and turn those into something that is actionable for developers. Then, on the business side, the threat models also help, ideally the threat models align with and understand those business goals and priorities. For example, if we say what's most important is protecting anywhere that we have open ports to the outside world. We need to consider our threat model there. Who are our customers and how are we authenticating those? How are we authorizing those calls that they make into our APIs, into any endpoint that we're exposing, and what data are they sending?

What data are we sending out to them and so on. So that in terms of the business side, a threat model can help with that, in terms of aligning those goals, aligning those priorities, and being able to focus on, where do we spend our time, where do we spend our money and so on to be able to accomplish some of those goals?

Michael Stiefel: This is actually quite interesting. One of the things that occurs to me when I listen to this, and you did a little bit of this when you described threat modeling, but there are people who are going to listen to this podcast who are developers. One of the biggest problems developers have or complaints is that this is not concrete enough. In other words, to me, one of the great skills in being a developer is being very literal minded. A computer has to be told the simplest things to do. In other words, if you build a table, if you don't screw in all the screws exactly right, the table is pretty secure, it's okay. But if you don't metaphorically tighten all the screws properly in the software application, you can have severe problems.

The problem I see that a lot of developers have when they listen, not so much the tactical security recommendations, but the strategic security implications, is that they're not concrete enough. I don't understand this. It seems to me, one of the roles of the architect and specifically the security architect, is to make this as concrete and as clear as possible to the developers so they're not left with something they feel, "Oh, this is just sort of mushy stuff."

Following the Unhappy Path [25:53]

Robert Hurlbut: Right, right. No, that's a great point. Well, one of the things that I've done, and I can remember doing this as a developer for many years, is to use unit tests and test driven development to think about how does my code react to tests, testing for functionality. But one thing that we don't always do as developers, I mean not every developer, but let's say initially they don't, is to think about the error cases.

Michael Stiefel: The unhappy path.

Robert Hurlbut: The unhappy path, thank you. The happy and the unhappy path. Yes, so the unhappy path. That's a lot of what we're doing in security, right? We are thinking about the unhappy path.

Michael Stiefel: Well, developers tend to be optimistic sort, I can do this, I can do that. The focus always is in the happy path, and you won't be surprised, and I no longer am surprised, but people don't even check error codes or don't even put catch handlers and have fallback points in their application to build. It's like they just expect the exception to be handled by the great exception handler in the sky without having any idea of what state the application is when they catch the exception.

Robert Hurlbut: Right, and so for concrete guidance for developers is to include those unhappy paths. What are the potential error conditions that you need to test for and validate that the code is able to handle those correctly? What do you expect if these happen? What's the error that I should see? Whether it be stored in the log file or returned back to the user on a screen. What should we see? Those kinds of things, not just the happy path, but the unhappy path. That's, again, where thinking through those security issues, those what could go wrong, that's a question that we ask quite often in threat modeling, what could go wrong?

Not a common question for everybody when they're thinking about the happy path, but when you think about the unhappy path, that really helps pinpoint what could go wrong here.

Application Recovery and Stability [28:05]

Michael Stiefel: Well, especially if you're, for example, in the middle of a transaction and some of it has to be rolled back and some of it doesn't. You also have to think about what the equilibrium or stable points are in the application. In other words, when you've handled the error, what's the state of the data? What's the state of the application? Can you go back? Let me pick a concrete example that's sort of... Let's say you are enrolling a new member and you have membership data, you have bank information, because let's say they're going to take some service that you charge for and you need all this information, but let's say there's an error in the application data.

Let's say they didn't put in, they left out some field, so do you throw everything away even though they got the account information for charges right, but they forgot some piece of information, you're going to throw it all away and they can enter them again? Of course, all the database gurus will tell you, don't have nulls in the database, but here's an example of from the user perspective or even the security perspective, because you have sensitive information that you may be gathering. Do you just throw it all away, make the user do it again, or do you save what you can and then somehow have an application state that says, this person can't go on until they enter this data?

Robert Hurlbut: Right, which are good decisions to make.

Michael Stiefel: Yes, and they're different for everybody. They depend on the business, but part of the unhappy path is thinking about how unhappy are you.

Robert Hurlbut: Right. How unhappy would we be if this happened?

Michael Stiefel: Right.

Robert Hurlbut: Yes.

Michael Stiefel: And how do you recover?

Robert Hurlbut: And how do you recover? Those are some things, in terms of concrete for developer, concrete action items, those are some things that could be really helpful in detailing for developers, here's what to look for, here's how to find those unhappy paths, react to them, deal with them, come back later, as you mentioned. Maybe if you have some information missing, how do I validate that I have information missing, that I need to maybe go and request that again from the user and so forth. Those are kinds of things. Again, it also reflect the business as well.

Conscious Decision Making [30:25]

Michael Stiefel: Absolutely. In fact, the developer can't make those decisions themselves. They need business constraints to make those decisions. What I like to tell people is, if you don't give that guidance to a developer, well, when the developer writes the if-then clause, for example, at 2:00 AM in the morning, they're going to make that decision de facto whether you like it or not.

Robert Hurlbut: Absolutely. What we like to say is, when we're talking about threat modeling and when I do training or just talking about in general with a team, is we always say, we're all threat modeling. Maybe it's new to everyone, but the reality is we're always threat modeling. We're always making decisions in our head. We're thinking about, "Okay, here's what I'm going to do. But what if that doesn't work?" We do that all the time. We go to cross the street, we look around both ways before we stepped off the curb.

Michael Stiefel: If we don't look both ways, that's a decision too.

Robert Hurlbut: That's a decision too, absolutely. We're making decisions all the time, and certainly developers are making decisions as they write code, and so we're already doing that. But the idea is that if we present that as a technique, but in some cases, like I said, I don't want to just simply make that decision for a developer, I need to know that's what I need to put in because that's based on our business rules, based on our requirements and so forth. That's what is going to really help.

Michael Stiefel: People have to understand that not to decide is to decide.

Robert Hurlbut: Is a decision. Absolutely.

Michael Stiefel: What you're essentially saying, it's better to make these decisions consciously, and if necessarily painfully, so you're aware of them. What I always like to say to people is, you don't want to wake up one morning and find out that your business is on the front page of the Wall Street Journal because you had some security breach.

Robert Hurlbut: Absolutely.

Michael Stiefel: That's what we used to call a career limiting move.

Evaluating Risk [32:25]

Robert Hurlbut: Well, and that's the value of security analysis, threat modeling, another word for it, secure architecture review, is doing that work so that you are aware. Because like you said, the worst thing is not being aware. If you're aware, at least at that point, you can make some decisions regarding risk. We haven't talked about that yet.

Michael Stiefel: Go ahead. Why don't you talk a little bit about risk? Because it is important.

Robert Hurlbut: Sure, sure. Absolutely important. We've talked a little bit about vulnerabilities indirectly. SQL injection is a vulnerability, usually based on a code error. Just doing something either intentionally or unintentionally, and it results in a vulnerability, which is basically a way for an attacker or a threat actor to be able to compromise the system using that particular vulnerability. The threat is, the result of that threat or that vulnerability rather being exploited, so the SQL injection example as a vulnerability, the threat would be somebody could use that to retrieve data, change data in the database. Maybe inherently it has more authority than the typical user should have. As a result, they can maybe drop the database.

I've seen that before in the middle of a demo, not so great. They could do that, so all kinds of potential threats. The risk comes into play when you become aware of those threats and then you evaluate those threats. What's the likelihood of that threat happening? Some threats are really difficult to do where you can say, "Well, if we had those vulnerabilities, maybe we can get access to the database, but maybe we have limited access to that database. Maybe the user that's calling the database is not an admin user, which we hope, but just a regular user. It only has access to that one database, that one table, that one whatever, and so the threat is limited.

But maybe that database is, for whatever reason, using an admin account to make the calls. Well, now you've got all the privileges and so your likelihood, and the other is the impact of that threat. First is the likelihood of that threat, and the second is the impact. If that threat was realized, if somebody was able to get to our database and be able to exfiltrate all the data in my database, what's the result? What could happen? Is that bad? Does that put us in the Wall Street Journal the next day, because everybody finds out we had a big data breach? That's where your risk comes in. That's what we usually say, is that combination of the likelihood and the ease of exploitation of that threat as well as the impact of that threat, if both are relatively high, we got a high risk.

If both are relatively low, we call it a low risk. Then, you evaluate in between, low to high, what are they? To get an idea of, if we don't fix this, if we don't, as we identify these threats, if we don't fix them, if we don't mitigate them, are we willing to accept that risk and the results of it losing some money, losing some reputation, or having a reputation impacted, or maybe transfer the risk? We just simply give a message. One common one I see is going into a coffee shop and it says, "We have open Wi-Fi here." Why do they tell you that? There's no password on the Wi-Fi? Well, you said, well, that's ease of use, right? But the reality is, that's transferring the risk to you.

You're responsible if you connect to something that's very sensitive, and so that's just transferring the risk to you. Then, other coffee shops will give you a password and provide it and so forth, and try to minimize the risk. The other, of course, is once you understand those risks, then you mitigate, and so then it minimizes the risk. But risk comes into play, just understanding what the threats are, understanding how likely these threats could be exploited and the impact of those threats. Then, that helps you then determine your next actions once you understand some of those risks.

Look at System Vulnerabilities, Not Scenarios [36:27]

Michael Stiefel: Something that you said raises something that I have thought about often in terms of threat modeling. Thinking about what the outside world could do versus what are the weaknesses of your system, it seems to me that if you try to think, and again, it depends on obviously your experience in your business, of what kind of outside actors and what could they do and what could be the scenarios? This is a huge number of them. But on the other hand, if you think of, as you were talking about before, about how vulnerable is our database? In some case, you don't care whether it's the Chinese government or some mobster trying to get in or some teenage hacker. You don't think of those scenarios.

You think of in terms of, what are the weaknesses of the database? What are the weaknesses of our authorization system? Focus on the internal weaknesses in your threat model as opposed to postulating what might happen. Because after all, it's the risks that you don't think of that really will get you. It's like the Secretary of Defense Rumsfeld used to say, there are the known knowns and there are the known unknowns, which a lot of what threat modeling is all about, but the unknown unknowns is what really is the problem. To me, one of the ways of getting at those unknown unknowns is to think of what the weaknesses of your system are as opposed to trying to think about what someone on the outside might do.

Robert Hurlbut: Absolutely. Another thing to consider in that regard is sometimes we'll spend, like you just said, a lot of time on beefing up our authentication protocols and process and so forth, which we should, don't get me wrong, that's important. But for services that say, all I have to do is, or for anybody to do to get into the system is they click on this link, they add themselves as a new user of the system, and now they have a login, guess what? Anybody can do that. Not just your customers, but also your attackers. Now, they have the same privileges as a regular user who's doing what you hope is a good thing, and the attacker who has very malicious intent. Now, it's beyond your authentication. They're all treated the same.

With that in mind, you don't know who the attacker is, if it's this regular user or if it's an attacker. But then like you said, you have to think about, how do I protect the system? What are the issues, security issues within my system that is not considering necessarily which user is what? We just need to make sure that we're protecting the system and understanding those security issues and resolving them for that very reason that you mentioned. We may or may never know, is this an insider, an outsider that's now become like an insider and going through the system? We don't know. But what we can know and to help us with the unknowns is, like you said, to focus on those issues.

Do Not Forget the End User Has a Job To Do [39:37]

Michael Stiefel: One last thing that I'd like to bring up before we get to the questions that I like to ask my guests is that sometimes people have to think about the advice they give to their end users as well as any development. One of my favorite pet peeves is the advice that people, I'm not talking about banks or financial institutions, because you have to understand the difference between internal and external attacks. But when people tell me I should change my password every 30 days, well, to me that's ridiculous. Because the only time that that will help you is if your password happens to be stolen in the small interval between when you change your password and they attack. But you have the other 29 days, 23 hours and 55 minutes of vulnerability.

That makes no sense to me. Now, again, in the bank, from an internal perspective, changing your password may be important because you want to make sure people who leave the bank... I'm trying to make this context specific, but sometimes people have this very blasé attitude towards security because they don't think of the convenience of the user and making it difficult for them. Instead of making people memorize gobbledygook passwords as opposed to long passphrases, which accomplish the same, you have to also think of not only the internals of the system, but users who will try to circumvent the security because they want to get their job done.

Robert Hurlbut: Right, right. No, good points. It's an interesting challenge for users and end users to help them understand some security basics, but also allow them to get their job done. Ultimately, that's another business goal. We want them to be able to do their work or do what they're doing because we want them to be successful. It reflects on us and so forth. But in terms of guidance in general, I know NIST, for example, which is a government agency that typically makes recommendations for security requirements and so forth a few years ago said, "Yes, no need to keep changing passwords all the time." It doesn't really serve a good purpose like you just mentioned. It's better to have a better password, phrases, and so forth.

Or, for end users, we can recommend password managers and there are some good tools out there for that to help them if they need to have a different password. The most common issue, of course, is everybody reusing the same password. If those get pulled out of a data breach and then used by attackers to continue to try to log into all kinds of systems, because they figure, "Well, that person probably used it elsewhere, we'll try it everywhere." We're adding numbers, let's just keep adding a number every time when we have to be forced to change the password, and that doesn't make it secure.

Michael Stiefel: Right, but people often do that because they're told to change their password every 15 days.

Robert Hurlbut: Right, instead of helped with other tools like password managers and so forth, and passphrases and things like that.

Michael Stiefel: Well, that actually raises an interesting question, that's going to get me a little far afield, but how much of these security attacks are automated and how much is somebody, a human looking at the data? Forget about AI now, let's not go there, using artificial intelligence for attacks, because I'm sure they're already thinking about that, if they haven't already done it.

Robert Hurlbut: Of course.

Michael Stiefel: Because big data analysis seem just right. You harvest a whole bunch of usernames, passwords, security credentials, past phrases, and you just machine learning. I'm sure governments have started to think about automated attacks on each other based on big data. But anyway, leave that aside. Something that you and I would have to worry about is if our password is stolen, let's say, which I'm sure because... or important data that has been stolen, because we know the credit card company, not credit card companies, but the credit scorers websites have been attacked. The information's out there. I'm sure my Social Security number is public knowledge on the dark somewhere because it's been stolen.

Do we assume that someone, unless you are a public figure and somebody wants to go after you, I presume most of these retries of these shared passwords are automatic. It's not someone's looking at Robert or Michael and saying, "Well, this is the pattern and let me figure this out." It's just automated.

Robert Hurlbut: It's automated. Yes. Lots and lots of bots that are doing this over and over again. One of the recommendations is for organizations to look at common password lists that may have the top 25,000 or 100,000 or more list of passwords. Whenever a user, end user sets up their login, they would put in their password and then compare it to that list and say, "Sorry, but you can't use that because it's part of our common compromised password list. Try again."

Michael Stiefel: I presume they're comparing them on a hash and encrypted basis?

Robert Hurlbut: Of course, right. Of course, of course. But the point is that can help with the end user, it helps the end user to not just put password one, or 12345, or something like that.

Michael Stiefel: Or, you can't use one of your last 10 passwords that you've... Yes. Is there anything else that you think is important to bring up that we haven't talked about that you can think of?

Robert Hurlbut: No. I think I've stressed this before, but just to highlight it again, is the importance of spending that time taking a look at the system, not so much as an attacker, but more as, I have these things I need to defend. I need to determine or understand where are there security issues within my system. It helps you then determine your risk. What can I fix today? What am I probably not going to fix because the risk is low? Because it's better to know than not know. I always recommend take some time, take a step back, look at your system, think about the threat model of some of the things that you're doing, the various business decisions that you're making, various activities, and so forth.

At least you'll have that, because if you don't, it's worse. It's better just to take a moment and review and understand, and that will pay dividends in the long run.

The Architect’s Questionnaire [46:17]

Michael Stiefel: Now, I get to the part of the podcast where I like to ask the questions, I'll ask all the architects, but it gives me insight into why people become architects, what they like about architects. It's not that I'm going to build any big data model of all the responses I get, but nonetheless, I think it's important for people to understand what makes an architect. What's your favorite part of being an architect?

Robert Hurlbut: For me, it is seeing that mixture of business, technology, of... Well, we like to sometimes go back to people, tools, and technology, or process. It's that combination of working with people, working with the business, working with the technology, and putting those together to build interesting designs, secure designs, of course, that's my main focus, but designs that really help us with the business goals, helps people to be able to do the work they're doing. That's really, in terms of being an architect, seeing all those things come together.

Michael Stiefel: What is your least favorite part of being an architect?

Robert Hurlbut: This one is a tough one. As a security architect, I probably would say more so than an application architect years ago, as a security architect is the challenge of getting folks to recognize the importance, again, of security. Even though I say everybody's talking about it, there are still holdouts, if you will, that say, security, we don't need that. We'll do it later. It'll come out in the wash eventually. The reality is, especially we talked about authorization, you cannot bolt that on. That's probably my least, is just still getting pushback occasionally on the need for security.

Michael Stiefel: Interesting. Is there anything creatively, spiritually, or emotionally about architecture or being an architect?

Robert Hurlbut: Well, actually, it goes back to my first one, but just the seeing something being built that was designed, seeing something that I've been a part of, or I've worked with thousands and thousands of teams, especially as a security architect, helping lots and lots of teams think about threat models. Seeing teams incorporate some of those techniques and ideas and taking a system that did well, but doing even better and improving in maybe even small ways, but there's improvement and more secure or better resiliency, better performance, and so on. Seeing those I think definitely is very fulfilling. There's some creative aspects to it too, but it's just that satisfying to see that.

Michael Stiefel: What turns you off about architecture or being an architect?

Robert Hurlbut: Not as much as it used to be, but sometimes long hours. Sometimes it can be in terms of, especially as you're designing and thinking through some really tough problems, a lot of things we've already solved, which is great. You can go back and review what are some patterns that are already out there to help us solve some problems, and that really helps. But then, there are some that say, well, this seems new, or this seems a little different. Taking the time and working through that can be a little challenging. It's not that I don't like it, but it certainly can be challenging. It can be time-consuming to work through some new things, especially if you're under a time crunch, which most of us are. Especially in many development teams and projects. That can be an interesting part of not being the most fun part.

Michael Stiefel: Not that you would prescribe them when they're not appropriate, but do you have any favorite technologies that you just love to work with?

Robert Hurlbut: Well, of course, as a developer, I always liked, and developer/architect, I liked IDEs on the Microsoft side. I've done C, C++, C#, .NET. I've also done some Java, so the various IDEs that came out. Any of those that help me build out some of the things that I'm developing but may also incorporate some, can I figure out what my components I'm building? Can I diagram them? Can I take a look at it? Does that tool help me with that? Some IDEs do, but apart from that, I think drawing tools have been really, certainly in the last number of years, good drawing tools. I don't have any particular that I can mention exactly, but just good drawing tools that help you visualize a system that you're building or thinking about.

Being able to draw those out, whether it's UML or data flow diagrams or some kind of flow diagram. Those are the things I really love, is helping to put ideas to a diagram that I can then use that to communicate with other people.

Michael Stiefel: What about architecture do you love?

Robert Hurlbut: I think the thing I love most about it is it's a foundation. When I was a developer, we're building things up from just a few lines of code, and then it becomes something else, it becomes something else. Now, I have many, many classes, many lines of code and all that sort of thing. But ultimately, it sits on a foundation, a design of some sort, and that's what I love. It's just seeing that foundation that all of these things rely on and the importance of it. That's what I think I enjoyed the most and love about it, is just it provides that good foundation and framework for all the things that we're talking about and doing and making decisions about and so forth.

Michael Stiefel: Conversely, what about architecture do you hate?

Robert Hurlbut: Hate is such a strong word.

Michael Stiefel: Well, that's why I picked it.

Robert Hurlbut: I know. I think the thing I hate the most is brittle architecture, because you could also, just like anything else, when you're building a foundation for a house, depending on if you put a good foundation in, it helps for a solid house. If you put a bad foundation or no foundation or all you're relying on is emergent foundation or architecture, if you have not put any thought to your architecture, you still have an architecture, but it's brittle. That's the thing I hate, is it will just happen, it will just happen. That to me is a mistake and that could be detrimental, especially as you move along and rely on some aspects of your design, of your architecture or emergent architecture.

Then, find out you have failures that are not being handled correctly and that's causing all kinds of issues later on, and it's harder to go back and fix that retroactively, very, very difficult.

Michael Stiefel: What profession, other than being an architect, would you like to attempt?

Robert Hurlbut: Well, as you mentioned at the very beginning, I am right now working on a PhD. It's in space cybersecurity. Actually, that's the next area of interest in terms of space infrastructure and architecture of systems and space systems and so forth. I'm looking at potential academia, looking at how I can help in other industries. I think still some aspects of architecture, but to be determined where that will go and where that will take me. But that's, I think, the next thing that I'm looking at that may or may not be related directly to architecture.

Michael Stiefel: Do you ever see yourself as not being an architect anymore?

Robert Hurlbut: I don't really think so. I think I will always have some aspect of... It's hard to, once you're in this a number of years, it's hard to see the system as not as an architect and understanding how things work and foundations and so forth. Yes, difficult for me to see that outside of what I'm doing now, that I won't be doing that for years and years to come.

Michael Stiefel: When a project is done, what do you like to hear from the clients or from your team?

Robert Hurlbut: That this helped us make a difference. That the work that we've done building out a good foundation, good architecture, secure architecture, resilient architecture, that this has made a difference. That's what I like to hear. That's what I like to see, and for teams to have that, hopefully, that feeling that we feel pretty good about what we built, really good about what we built and would like to do more of it.


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