Entries Tagged "threat models"

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The Unfalsifiability of Security Claims

Interesting research paper: Cormac Herley, “Unfalsifiability of security claims“:

There is an inherent asymmetry in computer security: things can be declared insecure by observation, but not the reverse. There is no observation that allows us to declare an arbitrary system or technique secure. We show that this implies that claims of necessary conditions for security (and sufficient conditions for insecurity) are unfalsifiable. This in turn implies an asymmetry in self-correction: while the claim that countermeasures are sufficient is always subject to correction, the claim that they are necessary is not. Thus, the response to new information can only be to ratchet upward: newly observed or speculated attack capabilities can argue a countermeasure in, but no possible observation argues one out. Further, when justifications are unfalsifiable, deciding the relative importance of defensive measures reduces to a subjective comparison of assumptions. Relying on such claims is the source of two problems: once we go wrong we stay wrong and errors accumulate, and we have no systematic way to rank or prioritize measures.

This is both true and not true.

Mostly, it’s true. It’s true in cryptography, where we can never say that an algorithm is secure. We can either show how it’s insecure, or say something like: all of these smart people have spent lots of hours trying to break it, and they can’t—but we don’t know what a smarter person who spends even more hours analyzing it will come up with. It’s true in things like airport security, where we can easily point out insecurities but are unable to similarly demonstrate that some measures are unnecessary. And this does lead to a ratcheting up on security, in the absence of constraints like budget or processing speed. It’s easier to demand that everyone take off their shoes for special screening, or that we add another four rounds to the cipher, than to argue the reverse.

But it’s not entirely true. It’s difficult, but we can analyze the cost-effectiveness of different security measures. We can compare them with each other. We can make estimations and decisions and optimizations. It’s just not easy, and often it’s more of an art than a science. But all is not lost.

Still, a very good paper and one worth reading.

Posted on May 27, 2016 at 6:19 AM • View Comments

Security vs. Business Flexibility

This article demonstrates that security is less important than functionality.

When asked about their preference if they needed to choose between IT security and business flexibility, 71 percent of respondents said that security should be equally or more important than business flexibility.

But show them the money and things change, when the same people were asked if they would take the risk of a potential security threat in order to achieve the biggest deal of their life, 69 percent of respondents say they would take the risk.

The reactions I’ve read call this a sad commentary on security, but I think it’s a perfectly reasonable result. Security is important, but when there’s an immediate conflicting requirement, security takes a back seat. I don’t think this is a problem of security literacy, or of awareness, or of training. It’s a consequence of our natural proclivity to take risks when the rewards are great.

Given the option, I would choose the security threat, too.

In the IT world, we need to recognize this reality. We need to build security that’s flexible and adaptable, that can respond to and mitigate security breaches, and can maintain security even in the face of business executives who would deliberately bypass security protection measures to achieve the biggest deal of their lives.

This essay previously appeared on Resilient Systems’s blog.

Posted on December 2, 2015 at 6:14 AM • View Comments

Mickens on Security

James Mickens, for your amusement. A somewhat random sample:

My point is that security people need to get their priorities straight. The “threat model” section of a security paper resembles the script for a telenovela that was written by a paranoid schizophrenic: there are elaborate narratives and grand conspiracy theories, and there are heroes and villains with fantastic (yet oddly constrained) powers that necessitate a grinding battle of emotional and technical attrition. In the real world, threat models are much simpler (see Figure 1). Basically, you’re either dealing with Mossad or not-Mossad. If your adversary is not-Mossad, then you’ll probably be fine if you pick a good password and don’t respond to emails from ChEaPestPAiNPi11s@virus-basket.biz.ru. If your adversary is the Mossad, YOU’RE GONNA DIE AND THERE’S NOTHING THAT YOU CAN DO ABOUT IT. The Mossad is not intimidated by the fact that you employ https://. If the Mossad wants your data, they’re going to use a drone to replace your cellphone with a piece of uranium that’s shaped like a cellphone, and when you die of tumors filled with tumors, they’re going to hold a press conference and say “It wasn’t us” as they wear t-shirts that say “IT WAS DEFINITELY US,” and then they’re going to buy all of your stuff at your estate sale so that they can directly look at the photos of your vacation instead of reading your insipid emails about them. In summary, https:// and two dollars will get you a bus ticket to nowhere. Also, SANTA CLAUS ISN’T REAL. When it rains, it pours.

Posted on August 28, 2015 at 3:58 PM • View Comments

Intimidating Military Personnel by Targeting Their Families

This FBI alert is interesting:

(U//FOUO) In May 2015, the wife of a US military member was approached in front of her home by two Middle-Eastern males. The men stated that she was the wife of a US interrogator. When she denied their claims, the men laughed. The two men left the area in a dark-colored, four-door sedan with two other Middle-Eastern males in the vehicle. The woman had observed the vehicle in the neighborhood on previous occasions.

(U//FOUO) Similar incidents in Wyoming have been reported to the FBI throughout June 2015. On numerous occasions, family members of military personnel were confronted by Middle-Eastern males in front of their homes. The males have attempted to obtain personal information about the military member and family members through intimidation. The family members have reported feeling scared.

The report says nothing about whether these are isolated incidents, a trend, or part of a larger operation. But it has gotten me thinking about the new ways military personnel can be intimidated. More and more military personnel live here and work there, remotely as drone pilots, intelligence analysts, and so on, and their military and personal lives intertwine to a degree we have not seen before. There will be some interesting security repercussions from that.

Posted on August 12, 2015 at 5:49 AM • View Comments

Should Companies Do Most of Their Computing in the Cloud? (Part 3)

Cloud computing is the future of computing. Specialization and outsourcing make society more efficient and scalable, and computing isn’t any different.

But why aren’t we there yet? Why don’t we, in Simon Crosby’s words, “get on with it”? I have discussed some reasons: loss of control, new and unquantifiable security risks, and—above all—a lack of trust. It is not enough to simply discount them, as the number of companies not embracing the cloud shows. It is more useful to consider what we need to do to bridge the trust gap.

A variety of mechanisms can create trust. When I outsourced my food preparation to a restaurant last night, it never occurred to me to worry about food safety. That blind trust is largely created by government regulation. It ensures that our food is safe to eat, just as it ensures our paint will not kill us and our planes are safe to fly. It is all well and good for Mr. Crosby to write that cloud companies “will invest heavily to ensure that they can satisfy complex…regulations,” but this presupposes that we have comprehensive regulations. Right now, it is largely a free-for-all out there, and it can be impossible to see how security in the cloud works. When robust consumer-safety regulations underpin outsourcing, people can trust the systems.

This is true for any kind of outsourcing. Attorneys, tax preparers and doctors are licensed and highly regulated, by both governments and professional organizations. We trust our doctors to cut open our bodies because we know they are not just making it up. We need a similar professionalism in cloud computing.

Reputation is another big part of trust. We rely on both word-of-mouth and professional reviews to decide on a particular car or restaurant. But none of that works without considerable transparency. Security is an example. Mr Crosby writes: “Cloud providers design security into their systems and dedicate enormous resources to protect their customers.” Maybe some do; many certainly do not. Without more transparency, as a cloud customer you cannot tell the difference. Try asking either Amazon Web Services or Salesforce.com to see the details of their security arrangements, or even to indemnify you for data breaches on their networks. It is even worse for free consumer cloud services like Gmail and iCloud.

We need to trust cloud computing’s performance, reliability and security. We need open standards, rules about being able to remove our data from cloud services, and the assurance that we can switch cloud services if we want to.

We also need to trust who has access to our data, and under what circumstances. One commenter wrote: “After Snowden, the idea of doing your computing in the cloud is preposterous.” He isn’t making a technical argument: a typical corporate data center isn’t any better defended than a cloud-computing one. He is making a legal argument. Under American law—and similar laws in other countries—the government can force your cloud provider to give up your data without your knowledge and consent. If your data is in your own data center, you at least get to see a copy of the court order.

Corporate surveillance matters, too. Many cloud companies mine and sell your data or use it to manipulate you into buying things. Blocking broad surveillance by both governments and corporations is critical to trusting the cloud, as is eliminating secret laws and orders regarding data access.

In the future, we will do all our computing in the cloud: both commodity computing and computing that requires personalized expertise. But this future will only come to pass when we manage to create trust in the cloud.

This essay previously appeared on the Economist website, as part of a debate on cloud computing. It’s the third of three essays. Here are Parts 1 and 2. Visit the site for the other side of the debate and other commentary.

Posted on June 10, 2015 at 3:27 PM • View Comments

Should Companies Do Most of Their Computing in the Cloud? (Part 2)

Let me start by describing two approaches to the cloud.

Most of the students I meet at Harvard University live their lives in the cloud. Their e-mail, documents, contacts, calendars, photos and everything else are stored on servers belonging to large internet companies in America and elsewhere. They use cloud services for everything. They converse and share on Facebook and Instagram and Twitter. They seamlessly switch among their laptops, tablets and phones. It wouldn’t be a stretch to say that they don’t really care where their computers end and the internet begins, and they are used to having immediate access to all of their data on the closest screen available.

In contrast, I personally use the cloud as little as possible. My e-mail is on my own computer—I am one of the last Eudora users—and not at a web service like Gmail or Hotmail. I don’t store my contacts or calendar in the cloud. I don’t use cloud backup. I don’t have personal accounts on social networking sites like Facebook or Twitter. (This makes me a freak, but highly productive.) And I don’t use many software and hardware products that I would otherwise really like, because they force you to keep your data in the cloud: Trello, Evernote, Fitbit.

Why don’t I embrace the cloud in the same way my younger colleagues do? There are three reasons, and they parallel the trade-offs corporations faced with the same decisions are going to make.

The first is control. I want to be in control of my data, and I don’t want to give it up. I have the ability to keep control by running my own services my way. Most of those students lack the technical expertise, and have no choice. They also want services that are only available on the cloud, and have no choice. I have deliberately made my life harder, simply to keep that control. Similarly, companies are going to decide whether or not they want to—or even can—keep control of their data.

The second is security. I talked about this at length in my opening statement. Suffice it to say that I am extremely paranoid about cloud security, and think I can do better. Lots of those students don’t care very much. Again, companies are going to have to make the same decision about who is going to do a better job, and depending on their own internal resources, they might make a different decision.

The third is the big one: trust. I simply don’t trust large corporations with my data. I know that, at least in America, they can sell my data at will and disclose it to whomever they want. It can be made public inadvertently by their lax security. My government can get access to it without a warrant. Again, lots of those students don’t care. And again, companies are going to have to make the same decisions.

Like any outsourcing relationship, cloud services are based on trust. If anything, that is what you should take away from this exchange. Try to do business only with trustworthy providers, and put contracts in place to ensure their trustworthiness. Push for government regulations that establish a baseline of trustworthiness for cases where you don’t have that negotiation power. Fight laws that give governments secret access to your data in the cloud. Cloud computing is the future of computing; we need to ensure that it is secure and reliable.

Despite my personal choices, my belief is that, in most cases, the benefits of cloud computing outweigh the risks. My company, Resilient Systems, uses cloud services both to run the business and to host our own products that we sell to other companies. For us it makes the most sense. But we spend a lot of effort ensuring that we use only trustworthy cloud providers, and that we are a trustworthy cloud provider to our own customers.

This essay previously appeared on the Economist website, as part of a debate on cloud computing. It’s the second of three essays. Here are Parts 1 and 3. Visit the site for the other side of the debate and other commentary.

Posted on June 10, 2015 at 11:27 AM • View Comments

Should Companies Do Most of Their Computing in the Cloud? (Part 1)

Yes. No. Yes. Maybe. Yes. Okay, it’s complicated.

The economics of cloud computing are compelling. For companies, the lower operating costs, the lack of capital expenditure, the ability to quickly scale and the ability to outsource maintenance are just some of the benefits. Computing is infrastructure, like cleaning, payroll, tax preparation and legal services. All of these are outsourced. And computing is becoming a utility, like power and water. Everyone does their power generation and water distribution “in the cloud.” Why should IT be any different?

Two reasons. The first is that IT is complicated: it is more like payroll services than like power generation. What this means is that you have to choose your cloud providers wisely, and make sure you have good contracts in place with them. You want to own your data, and be able to download that data at any time. You want assurances that your data will not disappear if the cloud provider goes out of business or discontinues your service. You want reliability and availability assurances, tech support assurances, whatever you need.

The downside is that you will have limited customization options. Cloud computing is cheaper because of economics of scale, and­—like any outsourced task—­you tend to get what you get. A restaurant with a limited menu is cheaper than a personal chef who can cook anything you want. Fewer options at a much cheaper price: it’s a feature, not a bug.

The second reason that cloud computing is different is security. This is not an idle concern. IT security is difficult under the best of circumstances, and security risks are one of the major reasons it has taken so long for companies to embrace the cloud. And here it really gets complicated.

On the pro-cloud side, cloud providers have the potential to be far more secure than the corporations whose data they are holding. It is the same economies of scale. For most companies, the cloud provider is likely to have better security than them­—by a lot. All but the largest companies benefit from the concentration of security expertise at the cloud provider.

On the anti-cloud side, the cloud provider might not meet your legal needs. You might have regulatory requirements that the cloud provider cannot meet. Your data might be stored in a country with laws you do not like­—or cannot legally use. Many foreign companies are thinking twice about putting their data inside America, because of laws allowing the government to get at that data in secret. Other countries around the world have even more draconian government-access rules.

Also on the anti-cloud side, a large cloud provider is a juicier target. Whether or not this matters depends on your threat profile. Criminals already steal far more credit card numbers than they can monetize; they are more likely to go after the smaller, less-defended networks. But a national intelligence agency will prefer the one-stop shop a cloud provider affords. That is why the NSA broke into Google’s data centers.

Finally, the loss of control is a security risk. Moving your data into the cloud means that someone else is controlling that data. This is fine if they do a good job, but terrible if they do not. And for free cloud services, that loss of control can be critical. The cloud provider can delete your data on a whim, if it believes you have violated some term of service that you never even knew existed. And you have no recourse.

As a business, you need to weigh the benefits against the risks. And that will depend on things like the type of cloud service you’re considering, the type of data that’s involved, how critical the service is, how easily you could do it in house, the size of your company and the regulatory environment, and so on.

This essay previously appeared on the Economist website, as part of a debate on cloud computing. It’s the first of three essays. Here are Parts 2 and 3. Visit the site for the other side of the debate and other commentary.

Posted on June 10, 2015 at 6:43 AM • View Comments

Adam Shostack's Threat Modeling

Probably the best IT security book of the year is Adam Shostack’s Threat Modeling (Amazon page).

The book is an honorable mention finalist for “The Best Books” of the past 12 months. This is the first time a security book has been on the list since my Applied Cryptography (first edition) won in 1994 and my Secrets and Lies won in 2001.

Anyway, Shostack’s book is really good, and I strongly recommend it. He blogs about the topic here.

Posted on November 3, 2014 at 7:40 AM • View Comments

Security Analysis of Children

This is a really good paper describing the unique threat model of children in the home, and the sorts of security philosophies that are effective in dealing with them. Stuart Schechter, “The User IS the Enemy, and (S)he Keeps Reaching for that Bright Shiny Power Button!” Definitely worth reading.

Abstract: Children represent a unique challenge to the security and privacy considerations of the home and technology deployed within it. While these challenges posed by children have long been researched, there is a gaping chasm between the traditional approaches technologists apply to problems of security and privacy and the approaches used by those who deal with this adversary on a regular basis. Indeed, addressing adversarial threats from children via traditional approaches to computer and information security would be a recipe for disaster: it is rarely appropriate to remove a child’s access to the home or its essential systems; children require flexibility; children are often threats to themselves; and children may use the home as a theater of conflict with each other. Further, the goals of security and privacy must be adjusted to account for the needs of childhood development. A home with perfect security—one that prevented all inappropriate behavior or at least ensured that it was recorded so that the adversary could be held accountable—could severely stunt children’s moral and personal growth. We discuss the challenges posed by children and childhood on technologies for the home, the philosophical gap between parenting and security technologists, and design approaches that technology designers could borrow when building systems to be deployed within homes containing this special class of user/adversary.

Posted on July 2, 2013 at 12:08 PM • View Comments

The Politics of Security in a Democracy

Terrorism causes fear, and we overreact to that fear. Our brains aren’t very good at probability and risk analysis. We tend to exaggerate spectacular, strange and rare events, and downplay ordinary, familiar and common ones. We think rare risks are more common than they are, and we fear them more than probability indicates we should.

Our leaders are just as prone to this overreaction as we are. But aside from basic psychology, there are other reasons that it’s smart politics to exaggerate terrorist threats, and security threats in general.

The first is that we respond to a strong leader. Bill Clinton famously said: “When people feel uncertain, they’d rather have somebody that’s strong and wrong than somebody who’s weak and right.” He’s right.

The second is that doing something—anything—is good politics. A politician wants to be seen as taking charge, demanding answers, fixing things. It just doesn’t look as good to sit back and claim that there’s nothing to do. The logic is along the lines of: “Something must be done. This is something. Therefore, we must do it.”

The third is that the “fear preacher” wins, regardless of the outcome. Imagine two politicians today. One of them preaches fear and draconian security measures. The other is someone like me, who tells people that terrorism is a negligible risk, that risk is part of life, and that while some security is necessary, we should mostly just refuse to be terrorized and get on with our lives.

Fast-forward 10 years. If I’m right and there have been no more terrorist attacks, the fear preacher takes credit for keeping us safe. But if a terrorist attack has occurred, my government career is over. Even if the incidence of terrorism is as ridiculously low as it is today, there’s no benefit for a politician to take my side of that gamble.

The fourth and final reason is money. Every new security technology, from surveillance cameras to high-tech fusion centers to airport full-body scanners, has a for-profit corporation lobbying for its purchase and use. Given the three other reasons above, it’s easy—and probably profitable—for a politician to make them happy and say yes.

For any given politician, the implications of these four reasons are straightforward. Overestimating the threat is better than underestimating it. Doing something about the threat is better than doing nothing. Doing something that is explicitly reactive is better than being proactive. (If you’re proactive and you’re wrong, you’ve wasted money. If you’re proactive and you’re right but no longer in power, whoever is in power is going to get the credit for what you did.) Visible is better than invisible. Creating something new is better than fixing something old.

Those last two maxims are why it’s better for a politician to fund a terrorist fusion center than to pay for more Arabic translators for the National Security Agency. No one’s going to see the additional appropriation in the NSA’s secret budget. On the other hand, a high-tech computerized fusion center is going to make front page news, even if it doesn’t actually do anything useful.

This leads to another phenomenon about security and government. Once a security system is in place, it can be very hard to dislodge it. Imagine a politician who objects to some aspect of airport security: the liquid ban, the shoe removal, something. If he pushes to relax security, he gets the blame if something bad happens as a result. No one wants to roll back a police power and have the lack of that power cause a well-publicized death, even if it’s a one-in-a-billion fluke.

We’re seeing this force at work in the bloated terrorist no-fly and watch lists; agents have lots of incentive to put someone on the list, but absolutely no incentive to take anyone off. We’re also seeing this in the Transportation Security Administration’s attempt to reverse the ban on small blades on airplanes. Twice it tried to make the change, and twice fearful politicians prevented it from going through with it.

Lots of unneeded and ineffective security measures are perpetrated by a government bureaucracy that is primarily concerned about the security of its members’ careers. They know the voters are more likely to punish them more if they fail to secure against a repetition of the last attack, and less if they fail to anticipate the next one.

What can we do? Well, the first step toward solving a problem is recognizing that you have one. These are not iron-clad rules; they’re tendencies. If we can keep these tendencies and their causes in mind, we’re more likely to end up with sensible security measures that are commensurate with the threat, instead of a lot of security theater and draconian police powers that are not.

Our leaders’ job is to resist these tendencies. Our job is to support politicians who do resist.

This essay originally appeared on CNN.com.

EDITED TO ADD (6/4): This essay has been translated into Swedish.

EDITED TO ADD (6/14): A similar essay, on the politics of terrorism defense.

Posted on May 28, 2013 at 5:09 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.