June 15, 2009
by Bruce Schneier
Chief Security Technology Officer, BT
A free monthly newsletter providing summaries, analyses, insights, and commentaries on security: computer and otherwise.
For back issues, or to subscribe, visit <http://www.schneier.com/crypto-gram.html>.
You can read this issue on the web at <http://www.schneier.com/crypto-gram-0906.html>. These same essays appear in the "Schneier on Security" blog: <http://www.schneier.com/blog>. An RSS feed is available.
In this issue:
- Obama's Cybersecurity Speech
- "Lost" Puzzle in Wired Magazine
- Last Month's Terrorism Arrests
- Me on Full-Body Scanners in Airports
- Schneier News
- The Doghouse: Net1
- Cloud Computing
- The Second Interdisciplinary Workshop on Security and Human Behaviour
- Comments from Readers
I am optimistic about President Obama's new cybersecurity policy and the appointment of a new "cybersecurity coordinator," though much depends on the details. What we do know is that the threats are real, from identity theft to Chinese hacking to cyberwar.
His principles were all welcome -- securing government networks, coordinating responses, working to secure the infrastructure in private hands (the power grid, the communications networks, and so on), although I think he's overly optimistic that legislation won't be required. I was especially heartened to hear his commitment to funding research. Much of the technology we currently use to secure cyberspace was developed from university research, and the more of it we finance today the more secure we'll be in a decade.
Education is also vital, although sometimes I think my parents need more cybersecurity education than my grandchildren do. I also appreciate the president's commitment to transparency and privacy, both of which are vital for security.
But the details matter. Centralizing security responsibilities has the downside of making security more brittle by instituting a single approach and a uniformity of thinking. Unless the new coordinator distributes responsibility, cybersecurity won't improve.
As the administration moves forward on the plan, two principles should apply. One, security decisions need to be made as close to the problem as possible. Protecting networks should be done by people who understand those networks, and threats needs to be assessed by people close to the threats. But distributed responsibility has more risk, so oversight is vital.
Two, security coordination needs to happen at the highest level possible, whether that's evaluating information about different threats, responding to an Internet worm or establishing guidelines for protecting personal information. The whole picture is larger than any single agency.
This essay originally appeared on The New York Times website, along with several others commenting on Obama's speech.
All the essays are worth reading, although I want to specifically quote James Bamford making an important point I've repeatedly made: "The history of White House czars is not a glorious one as anyone who has followed the rise and fall of the drug czars can tell. There is a lot of hype, a White House speech, and then things go back to normal. Power, the ability to cause change, depends primarily on who controls the money and who is closest to the president's ear. Because the new cyber czar will have neither a checkbook nor direct access to President Obama, the role will be more analogous to a traffic cop than a czar."
Gus Hosein wrote a good essay on the need for privacy: "Of course raising barriers around computer systems is certainly a good start. But when these systems are breached, our personal information is left vulnerable. Yet governments and companies are collecting more and more of our information. The presumption should be that all data collected is vulnerable to abuse or theft. We should therefore collect only what is absolutely required."
I wrote something similar to my essay above in 2002, about the creation of the Department of Homeland Security: "The human body defends itself through overlapping security systems. It has a complex immune system specifically to fight disease, but disease fighting is also distributed throughout every organ and every cell. The body has all sorts of security systems, ranging from your skin to keep harmful things out of your body, to your liver filtering harmful things from your bloodstream, to the defenses in your digestive system. These systems all do their own thing in their own way. They overlap each other, and to a certain extent one can compensate when another fails. It might seem redundant and inefficient, but it's more robust, reliable, and secure. You're alive and reading this because of it."
More news links on Obama's speech:
Good commentary from Gene Spafford:
Good commentary from Bob Blakley:
Me in 2002:
A copy of this essay, with all embedded links, is here:
For the April 09 issue of Wired Magazine, I was asked to create a cryptographic puzzle based on the television show Lost. Specifically, I was given a "clue" to encrypt.
Details are in the links. Creating something like this is very hard. The puzzle needs to be hard enough that people don't figure it out immediately, and easy enough that people eventually do figure it out. To make matters even more complicated, people will share their ideas on the Internet. So if the solution requires -- and I'm making this up -- expertise in Mayan history, carburetor design, algebraic topology, and Russian folk dancing, those people are likely to come together on the Internet. The puzzle has to be challenging for the group mind, not just for individual minds.
I have four points to make on the arrest of the three men for plotting to blow up synagogues in New York. One: There was little danger of an actual terrorist attack: "Authorities said the four men have long been under investigation and there was little danger they could actually have carried out their plan, NBC News' Pete Williams reported."
And: "'They never got anywhere close to being able to do anything,' one official told NBC News. 'Still, it's good to have guys like this off the street.'"
Of course, politicians are using this incident to peddle more fear: "'This was a very serious threat that could have cost many, many lives if it had gone through,' Representative Peter T. King, Republican from Long Island, said in an interview with WPIX-TV. 'It would have been a horrible, damaging tragedy. There's a real threat from homegrown terrorists and also from jailhouse converts.'"
Two, they were caught by traditional investigation and intelligence. Not airport security. Not warrantless eavesdropping. But old-fashioned investigation and intelligence. This is what works. This is what keeps us safe. I wrote an essay in 2004 that says exactly that. "The only effective way to deal with terrorists is through old-fashioned police and intelligence work -- discovering plans before they're implemented and then going after the plotters themselves."
Three, they were idiots: "The ringleader of the four-man homegrown terror cell accused of plotting to blow up synagogues in the Bronx and military planes in Newburgh admitted to a judge today that he had smoked pot before his bust last night.
"When U.S. Magistrate Judge Lisa M. Smith asked James Cromitie if his judgment was impaired during his appearance in federal court in White Plains, the 55-year-old confessed: 'No. I smoke it regularly. I understand everything you are saying.'"
Four, an "informant" helped this group a lot: "In April, Mr. Cromitie and the three other men selected the synagogues as their targets, the statement said. The informant soon helped them get the weapons, which were incapable of being fired or detonated, according to the authorities."
The warning I wrote in "Portrait of the Modern Terrorist as an Idiot" is timely again: "Despite the initial press frenzies, the actual details of the cases frequently turn out to be far less damning. Too often it's unclear whether the defendants are actually guilty, or if the police created a crime where none existed before."
Actually, that whole 2007 essay is timely again. Some things never change.
My "Portrait of the Modern Terrorist as an Idiot"
Kylin is a secure operating system from China. Seems to be a FreeBSD variant.
A great movie-plot threat: pirates in Chesapeake Bay.
Remember: if you don't like something, claim that it will enable, embolden, or entice terrorists. Works every time.
Invisible ink pen:
Microsoft bans memcopy() from its code base. Interesting discussion in comments about whether this helps, or is mostly cosmetic.
Your home/work location pair can uniquely identify you. This is very troubling, given the number of location-based services springing up and the number of databases that are collecting location data.
IEDs are now weapons of mass destruction.
Research into the insecurity of "secret questions."
Defending against movie-plot threats with movie characters:
Fantastic automatic dice thrower, a random number generator for computer games.
Steganography using TCP retransmission. I don't think these sorts of things have any large-scale applications, but they are clever.
What do you do if you have too many background checks to do for people's security clearances, and not enough time to do them?
It's all a matter of incentives. The investigators were rewarded for completing investigations, not for doing them well.
Man held for hours by immigration officials because he had no fingerprints:
And in other biometric news, four states have banned smiling in driver's license photographs.
Research on movie-plot threats: "Emerging Threats and Security Planning: How Should We Decide What Hypothetical Threats to Worry About?"
Secret government communications cables buried around Washington, DC:
This month's movie-plot idea: arming the Boston police with semi-automatic rifles:
I don't know how I missed this great series from Slate in February. It's eight essays exploring why there have been no follow-on terrorist attacks in the U.S. since 9/11 (not counting the anthrax mailings, I guess). Read the whole thing.
In May's Crypto-Gram, I blogged about the Boston police seizing a student's computer for, among other things, running Linux. Earlier this month, the Massachusetts Supreme Court threw out the search warrant.
This combination door lock is very pretty. Of course, four digits is too short an entry code, but I like the overall design and the automatic rescrambling feature. It's just a prototype, and not even a physical one at that.
Earlier this year, I blogged about a self-defense pen that is likely to easily pass through airport security. On the other hand, this normal pen in the shape of a bullet will probably get you in trouble.
Time for some more fear about terrorists using maps and images. (I thought I wrote a good blog post, but Crypto-Gram is already too long this month. So read it online, please.)
If you think that under-20-year-olds don't care about privacy, this is an eloquent op-ed by two students about why CCTV cameras have no place in their UK school.
Here's a site that sells corrupted MS Word files. The idea is that you e-mail one of the files to your professor when your homework is due, buying you a few hours -- or maybe days -- of extra time before your professor notices that it's corrupted. On the one hand, this is clever. But on the other hand, it's services like these that will force professors to treat corrupted attachments as work not yet turned in, and harm innocent homework submitters.
Here's how to make a corrupted pdf file for free:
Teaching children to spot terrorists: you can't make this stuff up.
Industry differences in types of security breaches.
Malware steals ATM data
I'm very happy with this quote in a CNN.com story on "whole-body imaging" at airports:
"Bruce Schneier, an internationally recognized security technologist, said whole-body imaging technology 'works pretty well,' privacy rights aside. But he thinks the financial investment was a mistake. In a post-9/11 world, he said, he knows his position isn't 'politically tenable,' but he believes money would be better spent on intelligence-gathering and investigations.
"'It's stupid to spend money so terrorists can change plans,' he said by phone from Poland, where he was speaking at a conference. If terrorists are swayed from going through airports, they'll just target other locations, such as a hotel in Mumbai, India, he said.
"'We'd be much better off going after bad guys ... and back to pre-9/11 levels of airport security,' he said. "There's a huge "cover your ass" factor in politics, but unfortunately, it doesn't make us safer.'"
I've written about "cover your ass" security in the past, but it's nice to see it in the press.
Me on CYA security:
Marcus Ranum and I did two video versions of our Face-Off column: one on cloud computing:
And the other on who should be in charge of cyber-security:
Another interview with me on cloud computing:
From its website: "The FTS Patent has been acclaimed by leading cryptographic authorities around the world as the most innovative and secure protocol ever invented to manage offline and online smart card related transactions. Please see the independent report by Bruce Schneider [sic] in his book entitled Applied Cryptography, 2nd Edition published in the late 1990s."
After I posted this on my blog, someone -- probably from the company -- said that it was referring to the UEPS protocol, discussed on page 589. I still don't like the hyperbole and the implied endorsement in the quote.
This year's overhyped IT concept is cloud computing. Also called software as a service (Saas), cloud computing is when you run software over the internet and access it via a browser. The Salesforce.com customer management software is an example of this. So is Google Docs. If you believe the hype, cloud computing is the future.
But hype aside, cloud computing is nothing new. It's the modern version of the timesharing model from the 1960s, which was eventually killed by the rise of the personal computer. It's what Hotmail and Gmail have been doing all these years, and it's social networking sites, remote backup companies, and remote email filtering companies such as MessageLabs. Any IT outsourcing -- network infrastructure, security monitoring, remote hosting -- is a form of cloud computing.
The old timesharing model arose because computers were expensive and hard to maintain. Modern computers and networks are drastically cheaper, but they're still hard to maintain. As networks have become faster, it is again easier to have someone else do the hard work. Computing has become more of a utility; users are more concerned with results than technical details, so the tech fades into the background.
But what about security? Isn't it more dangerous to have your email on Hotmail's servers, your spreadsheets on Google's, your personal conversations on Facebook's, and your company's sales prospects on salesforce.com's? Well, yes and no.
IT security is about trust. You have to trust your CPU manufacturer, your hardware, operating system and software vendors -- and your ISP. Any one of these can undermine your security: crash your systems, corrupt data, allow an attacker to get access to systems. We've spent decades dealing with worms and rootkits that target software vulnerabilities. We've worried about infected chips. But in the end, we have no choice but to blindly trust the security of the IT providers we use.
Saas moves the trust boundary out one step further -- you now have to also trust your software service vendors -- but it doesn't fundamentally change anything. It's just another vendor we need to trust.
There is one critical difference. When a computer is within your network, you can protect it with other security systems such as firewalls and IDSs. You can build a resilient system that works even if those vendors you have to trust may not be as trustworthy as you like. With any outsourcing model, whether it be cloud computing or something else, you can't. You have to trust your outsourcer completely. You not only have to trust the outsourcer's security, but its reliability, its availability, and its business continuity.
You don't want your critical data to be on some cloud computer that abruptly disappears because its owner goes bankrupt. You don't want the company you're using to be sold to your direct competitor. You don't want the company to cut corners, without warning, because times are tight. Or raise its prices and then refuse to let you have your data back. These things can happen with software vendors, but the results aren't as drastic.
There are two different types of cloud computing customers. The first only pays a nominal fee for these services -- and uses them for free in exchange for ads: e.g., Gmail and Facebook. These customers have no leverage with their outsourcers. You can lose everything. Companies like Google and Amazon won't spend a lot of time caring. The second type of customer pays considerably for these services: to Salesforce.com, MessageLabs, managed network companies, and so on. These customers have more leverage, providing they write their service contracts correctly. Still, nothing is guaranteed.
Trust is a concept as old as humanity, and the solutions are the same as they have always been. Be careful who you trust, be careful what you trust them with, and be careful how much you trust them. Outsourcing is the future of computing. Eventually we'll get this right, but you don't want to be a casualty along the way.
This essay originally appeared in The Guardian.
The reason I am talking so much about cloud computing is that reporters and inverviewers keep asking me about it. I feel kind of dragged into this whole thing.
At the Computers, Freedom, and Privacy conference earlier this month, Bob Gellman said that the nine most important words in cloud computing are: "terms of service," "location, location, location," and "provider, provider, provider" -- basically making the same point I did. You need to make sure the terms of service you sign up for are ones you can live with. You need to make sure the location of the provider doesn't subject you to any laws you can't live with. And you need to make sure your provider is someone you're willing to work with. Basically, if you're going to give someone else your data, you need to trust them.
A copy of this essay, with all embedded links, is here:
Last week, I was at SHB09, the Second Interdisciplinary Workshop on Security and Human Behaviour, at MIT. This was a two-day gathering of computer security researchers, psychologists, behavioral economists, sociologists, philosophers, and others -- all of whom are studying the human side of security -- organized by Ross Anderson, Alessandro Acquisti, and myself. I liveblogged the workshop; here are the talk summaries. (People were invited to submit a link for themselves, and links to applicable things they wrote. Those links will be included after each talk summary.)
The first session was about deception, moderated by David Clark.
Frank Stajano, Cambridge University, presented research with Paul Wilson, who films actual scams for "The Real Hustle." His point is that we build security systems based on our "logic," but users don't always follow our logic. It's fraudsters who really understand what people do, so we need to understand what the fraudsters understand. Things like distraction, greed, unknown accomplices, social compliance are important.
Understanding victims: Six principles for systems security
David Livingstone Smith, University of New England, is a philosopher by training, and goes back to basics: "What are we talking about?" A theoretical definition -- "that which something has to have to fall under a term" -- of deception is difficult to define. "Cause to have a false belief," from the Oxford English Dictionary, is inadequate. "To deceive is intentionally have someone to have a false belief" also doesn't work. "Intentionally causing someone to have a false belief that the speaker knows to be false" still isn't good enough. The fundamental problem is that these are anthropocentric definitions. Deception is not unique to humans; it gives organisms an evolutionary edge. For example, the mirror orchid fools a wasp into landing on it by looking like and giving off chemicals that mimic the female wasp. This example shows that we need a broader definition of "purpose." His formal definition: "For systems A and B, A deceives B iff A possesses some character C with proper function F, and B possesses a mechanism C* with the proper function F* of producing representations, such that the proper function of C is to cause C* to fail to perform F* by causing C* to form false representations, and C does so in virtue of performing F, and B's falsely representing enables some feature of A to perform its proper function."
Less than human: self-deception in the imagining of others
Talk on Lying at La Ciudad de Las Ideas
a subsequent discussion
I spoke next, about the psychology of Conficker, how the human brain buys security, and why science fiction writers shouldn't be hired to think about terrorism risks (to be published on Wired.com this week).
Dominic Johnson, University of Edinburgh, talked about his chapter in the book Natural Security: A Darwinian Approach to a Dangerous World. Life has 3.5 billion years of experience in security innovation; let's look at how biology approaches security. Biomimicry, ecology, paleontology, animal behavior, evolutionary psychology, immunology, epidemiology, selection, and adaption are all relevant. Redundancy is a very important survival tool for species. Here's an adaption example: The 9/11 threat was real and we knew about it, but we didn't do anything. His thesis: Adaptation to novel security threats tends to occur after major disasters. There are many historical examples of this; Pearl Harbor, for example. Causes include sensory biases, psychological biases, leadership biases, organizational biases, and political biases -- all pushing us towards maintaining the status quo. So it's natural for us to poorly adapt to security threats in the modern world. A questioner from the audience asked whether control theory had any relevance to this model.
Paradigm Shifts in Security Strategy
Perceptions of victory and defeat
Jeff Hancock, Cornell University, studies interpersonal deception: how the way we lie to each other intersects with communications technologies; and how technologies change the way we lie, and can technology be used to detect lying? Despite new technology, people lie for traditional reasons. For example: on dating sites, men tend to lie about their height and women tend to lie about their weight. The recordability of the Internet also changes how we lie. The use of the first person singular tends to go down the more people lie. He verified this in many spheres, such as how people describe themselves in chat rooms, and true versus false statements that the Bush administration made about 9/11 and Iraq. The effect was more pronounced when administration officials were answering questions than when they were reading prepared remarks.
On Lying and Being Lied To: A Linguistic Analysis of Deception in Computer-Mediated Communication
Separating Fact From Fiction: An Examination of Deceptive Self-Presentation in Online Dating Profiles
The second session was about fraud. (These session subjects are only general. We tried to stick related people together, but there was the occasional oddball -- and scheduling constraint -- to deal with.)
Julie Downs, Carnegie Mellon University, is a psychologist who studies how people make decisions, and talked about phishing. To determine how people respond to phishing attempts -- what e-mails they open and when they click on links -- she watched as people interacted with their e-mail. She found that most people's strategies to deal with phishing attacks might have been effective 5-10 years ago, but are no longer sufficient now that phishers have adapted. She also found that educating people about phishing didn't make them more effective at spotting phishing attempts, but made them more likely to be afraid of doing anything on line. She found this same overreaction among people who were recently the victims of phishing attacks, but again people were no better separating real e-mail from phishing attempts. What does make a difference is contextual understanding: how to parse a URL, how and why the scams happen, what SSL does and doesn't do.
Behavioral Response to Phishing Risk
Parents' vaccination comprehension and decisions
The Psychology of Food Consumption
Jean Camp, Indiana University, studies people taking risks online. Four points: 1) "people create mental models from internal narratives about risk," 2) "risk mitigating action is taken only if the risk is perceived as relevant," 3) "contextualizing risk can show risks as relevant," and 4) "narrative can increase desire and capacity to use security tools." Stories matter: "people are willing to wash out their cat food cans and sweep up their sweet gum balls to be a good neighbor, but allow their computers to join zombie networks" because there's a good story in the former and none in the latter. She presented two experiments to demonstrate this. One was a video experiment watching business majors try to install PGP. No one was successful: there was no narrative, and the mixed metaphor of physical and cryptographic "key" confused people.
Experimental Evaluation of Expert and Non-expert Computer Users' Mental Models of Security Risks
Matt Blaze, University of Pennsylvania, talked about electronic voting machines and fraud. He related the anecdote about actual electronic voting machine vote fraud in Kentucky from the second link. In the question session, he speculated about the difficulty of having a security model that would have captured the problem, and how to know whether that model was complete enough.
Electronic vote rigging in Kentucky
Jeffrey Friedberg, Microsoft, discussed research at Microsoft around the Trust User Experience (TUX). He talked about the difficulty of verifying SSL certificates. Then he talked about how Microsoft added a "green bar" to signify trusted sites, and how people who learned to trust the green bar were fooled by "picture in picture attacks": where a hostile site embedded a green-bar browser window in its page. Most people don't understand that the information inside the browser window is arbitrary, but that the stuff around it is not. The user interface, user experience, mental models all matter. Designing and evaluating TUX is hard. From the questions: training doesn't help much, because given a plausible story, people will do things counter to their training.
Internet Fraud Battlefield
End to End Trust and the Trust User Experience
Testimony on "spyware"
Stuart Schechter, Microsoft, presented this research on secret questions. Basically, secret questions don't work. They're easily guessable based on the most common answers; friends and relatives of people can easily predict unique answers; and people forget their answers. Even worse, the more memorable the question/answers are, the easier they are to guess. Having people write their own questions is no better: "What's my blood type?" "How tall am I?"
It's no secret
The Emperor's New Security Indicators
Tyler Moore, Harvard University, discussed his empirical studies on online crime and defense. Fraudsters are good at duping users, but they're also effective at exploiting failures among IT professionals to perpetuate the infrastructure necessary to carry out these exploits on a large scale (hosting fake web pages, sending spam, laundering the profits via money mules, and so on). There is widespread refusal among the defenders to cooperate with each other, and attackers exploit these limitations. We are better at removing phishing websites than we are at defending against the money mules. Defenders tend to fix immediate problems, but not underlying problems.
The Consequences of Non-Cooperation in the Fight Against Phishing
Information Security Economics -- and Beyond
In the discussion phase, there was a lot of talk about the relationships between websites, like banks, and users -- and how that affects security for both good and bad. Jean Camp doesn't want a relationship with her bank, because that unduly invests her in the bank. (Someone from the audience pointed out that, as a U.S. taxpayer, she is already invested in her bank.) Angela Sasse said that the correct metaphor is "rules of engagement," rather than relationships.
Session three was titled "Usability."
Andrew Patrick, NRC Canada until he was laid off four days ago, talked about biometric systems and human behavior. Biometrics are used everywhere: for gym membership, at Disneyworld, at international borders. The government of Canada is evaluating using iris recognition at a distance for events like the 2010 Olympics. There are two different usability issues: with respect to the end user, and with respect to the authenticator. People's acceptance of biometrics is very much dependent on the context. And of course, biometrics are not secret. Patrick suggested that to defend ourselves against this proliferation of using biometrics for authentication, the individual should publish them. The rationale is that we're publishing them anyway, so we might as well do it knowingly.
Fingerprint Concerns: Performance, Usability, and Acceptance of Fingerprint Biometric Systems
Luke Church, Cambridge University, talked about what he called "user-centered design." There's a economy of usability: "in order to make some things easier, we have to make some things harder" -- so it makes sense to make the commonly done things easier at the expense of the rarely done things. This has a lot of parallels with security. The result is "appliancisation" (with a prize for anyone who come up with a better name): the culmination of security behaviors and what the system can do embedded in a series of user choices. Basically, giving users meaningful control over their security. Luke discussed several benefits and problems with the approach.
SHB Position Paper
Usability and the Common Criteria
Diana Smetters, Palo Alto Research Center, started with these premises: you can teach users, but you can't teach them very much, so you'd better carefully design systems so that you 1) minimize what they have to learn, 2) make it easier for them to learn it, and 3) maximize the benefit from what they learn. Too often, security is at odds with getting the job done. "As long as configuration errors (false alarms) are common, any technology that requires users to observe security indicators and react to them will fail as attacks can simply masquerade as errors, and users will rationally ignore them." She recommends meeting the user halfway by building new security models that actually fit the users' needs. (For example: Phishing is a mismatch problem, between what's in the user's head and where the URL is actually going. SSL doesn't work, but how should websites authenticate themselves to users? Her solution is protected links: a set of secure bookmarks in protected browsers. She went on to describe a prototype and tests run with user subjects.
Breaking out of the browser to defend against phishing attacks
Building secure mashups
Ad-hoc guesting: when exceptions are the rule
Jon Callas, PGP Corporation, used the metaphor of the "security cliff": you have to keep climbing until you get to the top and that's hard, so it's easier to just stay at the bottom. He wants more of a "security ramp," so people can reasonably stop somewhere in the middle. His idea is to have a few policies -- e-mail encryption, rules about USB drives -- and enforce them. This works well in organizations, where IT has dictatorial control over user configuration. If we can't teach users much, we need to enforce policies on users.
Improving Message Security With a Self-Assembling PKI
Rob Reeder, Microsoft, presented a possible solution to the secret questions problem: social authentication. The idea is to use people you know (trustees) to authenticate who you are, and have them attest to the fact that you lost your password. He went on to describe how the protocol works, as well as several potential attacks against the protocol and defenses, and experiments that tested the protocol. In the question session he talked about people designating themselves as trustees, and how that isn't really a problem.
Expanding Grids for Visualizing and Authoring Computer Security Policies
Lorrie Cranor, Carnegie Mellon University, talked about security warnings. The best option is to fix the hazard; the second best is to guard against it -- but far too often we just warn people about it. But since hazards are generally not very hazardous, most people just ignore them. "Often, software asks the user and provides little or no information to help user make this decision." Better is to use some sort of automated analysis to assist the user in responding to warnings. For websites, for example, the system should block sites with a high probability of danger, not bother users if there is a low probably of danger, and help the user make the decision in the grey area. She went on to describe a prototype and user studies done with the prototype; her paper will be presented at USENIX Security in August.
A Framework for Reasoning About the Human in the Loop
Timing Is Everything? The Effects of Timing and Placement of Online Privacy Indicators
School of Phish: A Real-Word Evaluation of Anti-Phishing Training
You've Been Warned: An Empirical Study of the Effectiveness of Web Browser Phishing Warnings
Much of the discussion centered on how bad the problem really is, and how much security is good enough. The group also talked about economic incentives companies have to either fix or ignore security problems, and whether market approaches (or, as Jean Camp called it, "the happy Libertarian market pony") are sufficient. Some companies have incentives to convince users to do the wrong thing, or at the very least to do nothing. For example, social networking sites are more valuable if people share their information widely.
Further discussion was about whitelisting, and whether it worked or not. There's the problem of the bad guys getting on the whitelist, and the risk that organizations like the RIAA will use the whitelist to enforce copyright, or that large banks will use the whitelist as a tool to block smaller start-up banks. Another problem is that the user might not understand what a whitelist signifies.
Dave Clark from the audience: "It's not hard to put a seat belt on, and if you need a lesson, take a plane." Kind of a one-note session. We definitely need to invite more psych people next time.
David Livingstone Smith moderated the fourth session, about (more or less) methodology.
Angela Sasse, University College London, has been working on usable security for over a dozen years. As part of a project called "Trust Economics," she looked at whether people comply with security policies and why they either do or do not. She found that there is a limit to the amount of effort people will make to comply -- this is less actual cost and more perceived cost. Strict and simple policies will be complied with more than permissive but complex policies. Compliance detection, and reward or punishment, also affect compliance. People justify noncompliance by "frequently made excuses."
The Compliance Budget: Managing Security Behaviour in Organisations
Human Vulnerabilities in Security Systems
Bashar Nuseibeh, Open University, talked about mobile phone security; specifically, Facebook privacy on mobile phones. He did something clever in his experiments. Because he wasn't able to interview people at the moment they did something -- he worked with mobile users -- he asked them to provide a "memory phrase" that allowed him to effectively conduct detailed interviews at a later time. This worked very well, and resulted in all sorts of information about why people made privacy decisions at that earlier time.
A Multi-Pronged Empirical Approach to Mobile Privacy Investigation
Security Requirements Engineering: A Framework for Representation and Analysis
James Pita, University of Southern California, studies security personnel who have to guard a physical location. In his analysis, there are limited resources -- guards, cameras, etc. -- and a set of locations that need to be guarded. An example would be the Los Angeles airport, where a finite number of K-9 units need to guard eight terminals. His model uses a Stackelberg game to minimize predictability (otherwise, the adversary will learn it and exploit it) while maximizing security. There are complications -- observational uncertainty and bounded rationally on the part of the attackers -- which he tried to capture in his model.
Deployed ARMOR Protection: The Application of a Game Theoretic Model for Security at the Los Angeles International Airport
Markus Jakobsson, Palo Alto Research Center, pointed out that auto insurers ask people if they smoke in order to get a feeling for whether they engage in high-risk behaviors. In his experiment, he selected 100 people who were the victim of online fraud and 100 people who were not. He then asked them to complete a survey about different physical risks such as mountain climbing and parachute jumping, financial risks such as buying stocks and real estate, and Internet risks such as visiting porn sites and using public wi-fi networks. He found significant correlation between different risks, but I didn't see an overall pattern emerge. And in the discussion phase, several people had questions about the data. More analysis, and probably more data, is required. To be fair, he was still in the middle of his analysis.
Male, late with your credit card payment, and like to speed? You will be phished!
Love and Authentication
Quantifying the Security of Preference-Based Authentication
Rachel Greenstadt, Drexel University, discussed ways in which humans and machines can collaborate in making security decisions. These decisions are hard for several reasons: because they are context dependent, require specialized knowledge, are dynamic, and require complex risk analysis. And humans and machines are good at different sorts of tasks. Machine-style authentication: This guy I'm standing next to knows Jake's private key, so he must be Jake. Human-style authentication: This guy I'm standing next to looks like Jake and sounds like Jake, so he must be Jake. The trick is to design systems that get the best of these two authentication styles and not the worst. She described two experiments examining two decisions: should I log into this website (the phishing problem), and should I publish this anonymous essay or will my linguistic style betray me?
Practical Attacks Against Authorship Recognition Techniques (pre-print)
Reinterpreting the Disclosure Debate for Web Infections
Mike Roe, Microsoft, talked about crime in online games, particularly in Second Life and Metaplace. There are four classes of people on online games: explorers, socializers, achievers, and griefers. Griefers try to annoy socializers in social worlds like Second Life, or annoy achievers in competitive worlds like World of Warcraft. Crime is not necessarily economic; criminals trying to steal money is much less of a problem in these games than people just trying to be annoying. In the question session, Dave Clark said that griefers are a constant, but economic fraud grows over time. I responded that the two types of attackers are different people, with different personality profiles. I also pointed out that there is another kind of attacker: achievers who use illegal mechanisms to assist themselves.
In the discussion, Peter Neumann pointed out that safety is an emergent property, and requires security, reliability, and survivability. Others weren't so sure.
The first session of the second day was "Foundations," which is kind of a catch-all for a variety of things that didn't really fit anywhere else. Rachel Greenstadt moderated.
Terence Taylor, International Council for the Live Sciences, talked about the lessons evolution teaches about living with risk. Successful species didn't survive by eliminating the risks of their environment, they survived by adaptation. Adaptation isn't always what you think. For example, you could view the collapse of the Soviet Union as a failure to adapt, but you could also view it as successful adaptation. Risk is good. Risk is essential for the survival of a society, because risk-takers are the drivers of change. In the discussion phase, John Mueller pointed out a key difference between human and biological systems: humans tend to respond dramatically to anomalous events (the anthrax attacks), while biological systems respond to sustained change. And David Livingstone Smith asked about the difference between biological adaptation that affects the reproductive success of an organism's genes, even at the expense of the organism, with security adaptation. (I recommend the book he edited: Natural Security: A Darwinian Approach to a Dangerous World.)
Andrew Odlyzko, University of Minnesota, discussed human-space vs. cyberspace. People cannot build secure systems -- we know that -- but people also cannot live with secure systems. We require a certain amount of flexibility in our systems. And finally, people don't need secure systems. We survive with an astounding amount of insecurity in our world. The problem with cyberspace is that it was originally conceived as separate from the physical world, and that it could correct for the inadequacies of the physical world. Really, the two are intertwined, and that human space more often corrects for the inadequacies of cyberspace. Lessons: build messy systems, not clean ones; create a web of ties to other systems; create permanent records.
Network Neutrality, Search Neutrality, and the Never-Ending Conflict Between Efficiency and Fairness in Markets
Economics, psychology, and sociology of security
danah boyd, Microsoft Research, does ethnographic studies of teens in cyberspace. Teens tend not to lie to their friends in cyberspace, but they lie to the system. Since an early age, they've been taught that they need to lie online to be safe. Teens regularly share their passwords: with their parents when forced, or with their best friend or significant other. This is a way of demonstrating trust. It's part of the social protocol for this generation. In general, teens don't use social media in the same way as adults do. And when they grow up, they won't use social media in the same way as today's adults do. Teens view privacy in terms of control, and take their cues about privacy from celebrities and how they use social media. And their sense of privacy is much more nuanced and complicated. In the discussion phase, danah wasn't sure whether the younger generation would be more or less susceptible to Internet scams than the rest of us -- they're not nearly as technically savvy as we might think they are. "The only thing that saves teenagers is fear of their parents"; they try to lock them out, and lock others out in the process. Socio-economic status matters a lot, in ways that she is still trying to figure out. There are three different types of social networks: personal networks, articulated networks, and behavioral networks, and they're different.
Taken Out of Context -- American Teen Sociality in Networked Publics
Mark Levine, Lancaster University. He collected data from UK CCTV cameras, searches for aggressive behavior, and studies when and how bystanders either help escalate or de-escalate the situations. Results: as groups get bigger, there is no increase of anti-social acts and a significant increase in pro-social acts. He has much more analysis and results, too complicated to summarize here. One key finding: when a third party intervenes in an aggressive interaction, it is much more likely to de-escalate. Basically, groups can act against violence. "When it comes to violence (and security), group processes are part of the solution -- not part of the problem?"
The Kindness of Crowds
Intra-group Regulation of Violence: Bystanders and the (De)-escalation of Violence
Jeff MacKie-Mason, University of Michigan, is an economist: "Security problems are incentive problems." He discussed motivation, and how to design systems to take motivation into account. Humans are smart devices; they can't be programmed, but they can be influenced through the sciences of motivational behavior: microeconomics, game theory, social psychology, psychodynamics, and personality psychology. He gave a couple of general examples of how these theories can inform security system design.
Humans are smart devices, but not programmable
Security when people matter
A Social Mechanism for Supporting Home Computer Security
Joe Bonneau, Cambridge University, talked about social networks like Facebook, and privacy. People misunderstand why privacy and security is important in social networking sites like Facebook. People underestimate of what Facebook really is; it really is a reimplementation of the entire Internet. "Everything on the Internet is becoming social," and that makes security different. Phishing is different, 419-style scams are different. Social context makes some scams easier; social networks are fun, noisy, and unpredictable. "People use social networking systems with their brain turned off." But social context can be used to spot frauds and anomalies, and can be used to establish trust.
Session Six -- "Terror" -- chaired by Stuart Schechter.
Bill Burns, Decision Research, studies social reaction to risk. He discussed his theoretical model of how people react to fear events, and data from the 9/11 attacks, the 7/7 bombings in the UK, and the 2008 financial collapse. Basically, we can't remain fearful. No matter what happens, fear spikes immediately after and recovers 45 or so days afterwards. He believes that the greatest mistake we made after 9/11 was labeling the event as terrorism instead of an international crime.
The Diffusion of Fear: Modeling Community Response to a Terrorist Strike
Chris Cocking, London Metropolitan University, looks at the group behavior of people responding to emergencies. Traditionally, most emergency planning is based on the panic model: people in crowds are prone to irrational behavior and panic. There's also a social attachment model that predicts that social norms don't break down in groups. He prefers a self-categorization approach: disasters create a common identity, which results in orderly and altruistic behavior among strangers. The greater the threat, the greater the common identity, and spontaneous resilience can occur. He displayed a photograph of "panic" in New York on 9/11 and showed how it wasn't panic at all. Panic seems to be more a myth than a reality. This has policy implications during an event: provide people with information, and people are more likely to underreact than overreact, if there is overreaction, it's because people are acting as individuals rather than groups, so those in authority should encourage a sense of collective identity. "Crowds can be part of the solution rather than part of the problem."
Effects of social identity on responses to emergency mass evacuation
Richard John, University of Southern California, talked about the process of social amplification of risk (with respect to terrorism). Events result in relatively small losses; it's the changes in behavior following an event that result in much greater losses. There's a dynamic of risk perception, and it's very contextual. He uses vignettes to study how risk perception changes over time, and discussed some of the studies he's conducting and ideas for future studies.
Decision Analysis by Proxy for the Rational Terrorist
Mark Stewart, University of Newcastle, Australia, examines infrastructure security and whether the costs exceed the benefits. He talked about cost/benefit trade-off, and how to apply probabilistic terrorism risk assessment; then, he tried to apply this model to the U.S. Federal Air Marshal Service. His result: they're not worth it. You can quibble with his data, but the real value is a transparent process. During the discussion, I said that it is important to realize that risks can't be taken in isolation, that anyone making a security trade-off is balancing several risks: terrorism risks, political risks, the personal risks to his career, etc.
A risk and cost-benefit assessment of United States aviation security measures
Risk and Cost-Benefit Assessment of Counter-Terrorism Protective Measures to Infrastructure
John Adams, University College London, applies his risk thermostat model to terrorism. He presented a series of amusing photographs of overreactions to risk, most of them not really about risk aversion but more about liability aversion. He talked about bureaucratic paranoia, as well as bureaucratic incitements to paranoia, and how this is beginning to backfire. People treat risks differently, depending on whether they are voluntary, impersonal, or imposed, and whether people have total control, diminished control, or no control.
Deus e Brasileiro?
Can Science Beat Terrorism?
Bicycle bombs: a further inquiry
Dan Gardner, Ottawa Citizen, talked about how the media covers risks, threats, attacks, etc. He talked about the various ways the media screws up, all of which were familiar to everyone. His thesis is not that the media gets things wrong in order to increase readership/viewership and therefore profits, but that the media gets things wrong because reporters are human. Bad news bias is not a result of the media hyping bad news, but the natural human tendency to remember the bad more than the good. The evening news is centered around stories because people -- including reporters -- respond to stories, and stories with novelty, emotion, and drama are better stories.
Some of the discussion was about the nature of panic: whether and where it exists, and what it looks like. Someone from the audience questioned whether panic was related to proximity to the event; someone else pointed out that people very close to the 7/7 bombings took pictures and made phone calls -- and that there was no evidence of panic. Also, on 9/11 pretty much everyone below where the airplanes struck the World Trade Center got out safely; and everyone above couldn't get out, and died. Angela Sasse pointed out that the previous terrorist attack against the World Trade Center, and the changes made in evacuation procedures afterwards, contributed to the lack of panic on 9/11. Bill Burns said that the purest form of panic is a drowning person. Jean Camp asked whether the recent attacks against women's health providers should be classified as terrorism, or whether we are better off framing it as crime. There was also talk about sky marshals and their effectiveness. I said that it isn't sky marshals that are a deterrent, but the idea of sky marshals. Terence Taylor said that increasing uncertainty on the part of the terrorists is, in itself, a security measure. There was also a discussion about how risk-averse terrorists are; they seem to want to believe they have an 80% or 90% change of success before they will launch an attack.
The penultimate session of the conference was "Privacy," moderated by Tyler Moore.
Alessandro Acquisti, Carnegie Mellon University, presented research on how people value their privacy. He started by listing a variety of cognitive biases that affect privacy decisions: illusion of control, overconfidence, optimism bias, endowment effect, and so on. He discussed two experiments. The first demonstrated a "herding effect": if a subject believes that others reveal sensitive behavior, the subject is more likely to also reveal sensitive behavior. The second examined the "frog effect": do privacy intrusions alert or desensitize people to revealing personal information? What he found is that people tend to set their privacy level at the beginning of a survey, and don't respond well to being asked easy questions at first and then sensitive questions at the end. In the discussion, Joe Bonneau asked him about the notion that people's privacy protections tend to ratchet up over time; he didn't have conclusive evidence, but gave several possible explanations for the phenomenon.
What Can Behavioral Economics Teach Us About Privacy?
Privacy in Electronic Commerce and the Economics of Immediate Gratification
Adam Joinson, University of Bath, also studies how people value their privacy. He talked about expressive privacy -- privacy that allows people to express themselves and form interpersonal relationships. His research showed that differences between how people use Facebook in different countries depend on how much people trust Facebook as a company, rather than how much people trust other Facebook users. Another study looked at posts from Secret Tweet and Twitter. He found 16 markers that allowed him to automatically determine which tweets contain sensitive personal information and which do not, with high probability. Then he tried to determine if people with large Twitter followings post fewer secrets than people who are only twittering to a few people. He found absolutely no difference.
Privacy, Trust and Self-Disclosure Online
Privacy concerns and privacy actions
Peter Neumann, SRI, talked about lack of medical privacy (too many people have access to your data), about voting (the privacy problem makes the voting problem a lot harder, and the end-to-end voting security/privacy problem is much harder than just securing voting machines), and privacy in China (the government is requiring all computers sold in China to be sold with software allowing them to eavesdrop on the users). Any would-be solution needs to reflect the ubiquity of the threat. When we design systems, we need to anticipate what the privacy problems will be. Privacy problems are everywhere you look, and ordinary people have no idea of the depth of the problem.
Identity and Trust in Context
Eric Johnson, Dartmouth College, studies the information access problem from a business perspective. He's been doing field studies in companies like retail banks and investment banks, and found that role-based access control fails because companies can't determine who has what role. Even worse, roles change quickly, especially in large complex organizations. For example, one business group of 3000 people experiences 1000 role changes within three months. The result is that organizations do access control badly, either over-entitling or under-entitling people. But since getting the job done is the most important thing, organizations tend to over-entitle: give people more access than they need. His current work is to find the right set of incentives and controls to set access more properly. The challege is to do this without making people risk averse. In the discussion, he agreed that a perfect access control system is not possible, and that organizations should probably allow a certain amount of access control violations -- similar to the idea of posting a 55 mph speed limit but not ticketing people unless they go over 70 mph.
Access Flexibility with Escalation and Audit
Security through Information Risk Management
Christine Jolls, Yale Law School, made the point that people regularly share their most private information with their intimates -- so privacy is not about secrecy, it's more about control. There are moments when people make pretty big privacy decisions. For example, they grant employers the rights to monitor their e-mail, or test their urine without notice. In general, courts hold that blanket signing away of privacy rights -- "you can test my urine on any day in the future" -- are not valid, but immediate signing away of privacy of privacy rights -- "you can test my urine today" -- are. Jolls believes that this is reasonable for several reasons, such as optimism bias and an overfocus on the present at the expense of the future. Without realizing it, the courts have implemented the system that behavioral economics would find optimal. During the discussion, she talked about how coercion figures into this; the U.S. legal system tends not to be concerned with it.
Rationality and Consent in Privacy Law
Andrew Adams, University of Reading, also looks at attitudes of privacy on social networking services. His results are preliminary, and based on interviews with university students in Canada, Japan, and the UK, and are very concordant with what danah boyd and Joe Bonneau said earlier. From the UK: People join social networking sites to increase their level of interaction with people they already know in real life. Revealing personal information is okay, but revealing too much is bad. Even more interestingly, it's not okay to reveal more about others than they reveal themselves. From Japan: People are more open to making friends online. There's more anonymity. It's not okay to reveal information about others, but "the fault of this lies as much with the person whose data was revealed in not choosing friends wisely." This victim responsibility is a common theme with other privacy and security elements in Japan. Data from Canada is still being compiled.
Great phrase: the "laundry belt" -- close enough for students to go home on weekends with their laundry, but far enough away so they don't feel as if their parents are looking over their shoulder -- typically two hours by public transportation (in the UK).
The eighth, and final, session of the SHB09 was optimistically titled "How Do We Fix the World?" I moderated, which meant that my liveblogging was more spotty, especially in the discussion section.
David Mandel, Defense Research and Development Canada, is part of the Thinking, Risk, and Intelligence Group at DRDC Toronto. His first observation: "Be wary of purported world-fixers." His second observation: when you claim that something is broken, it is important to specify the respects in which it's broken and what fixed looks like. His third observation: it is also important to analyze the consequences of any potential fix. An analysis of the way things are is perceptually based, but an analysis of the way things should be is value-based. He also presented data showing that predictions made by intelligence analysts (at least in one Canadian organization) were pretty good.
Applied Behavioral Science in Support of Intelligence Analysis
Radicalization: What does it mean?
The Role of Instigators in Radicalization to Violent Extremism
Ross Anderson, Cambridge University, asked "Where's the equilibrium?" Both privacy and security are moving targets, but he expects that someday soon there will be a societal equilibrium. Incentives to price discriminate go up, and the cost to do so goes down. He gave several examples of database systems that reached very different equilibrium points, depending on corporate lobbying, political realities, public outrage, etc. He believes that privacy will be regulated, the only question being when and how. "Where will the privacy boundary end up, and why? How can we nudge it one way or another?"
book chapters on psychology and terror
Alma Whitten, Google, presented a set of ideals about privacy (very European like) and some of the engineering challenges they present. "Engineering challenge #1: How to support access and control to personal data that isn't authenticated? Engineering challenge #2: How to inform users about both authenticated and unauthenticated data? Engineering challenge #3: How to balance giving users control over data collection versus detecting and stopping abuse? Engineering challenge #4: How to give users fine-grained control over their data without overwhelming them with options? Engineering challenge #5: How to link sequential actions while preventing them from being linkable to a person? Engineering challenge #6: How to make the benefits of aggregate data analysis apparent to users? Engineering challenge #7: How to avoid or detect inadvertent recording of data that can be linked to an individual?" (Note that Alma requested not to be recorded.)
Why Johnny can't encrypt: A usability evaluation of PGP 5.0
John Mueller, Ohio State University, talked about terrorism and the Department of Homeland Security. Terrorism isn't a threat; it's a problem and a concern, certainly, but the word "threat" is still extreme. Al Qaeda isn't a threat, and they're the most serious potential attacker against the U.S. and Western Europe. And terrorists are overwhelmingly stupid. Meanwhile, the terrorism issue "has become a self-licking ice cream cone." In other words, it's now an ever-perpetuating government bureaucracy. There are virtually an infinite number of targets; the odds of any one target being targeted is effectively zero; terrorists pick targets largely at random; if you protect target, it makes other targets less safe; most targets are vulnerable in the physical sense, but invulnerable in the sense that they can be rebuilt relatively cheaply (even something like the Pentagon); some targets simply can't be protected; if you're going to protect some targets, you need to determine if they should really be protected. (I recommend his book, Overblown.)
Reacting to Terrorism: Probabilities, Consequences, and the Persistence of Fear
Evaluating Measures to Protect the Homeland from Terrorism
Terrorphobia: Our False Sense of Insecurity
Adam Shostack, Microsoft, pointed out that even the problem of figuring out what part of the problem to work on first is difficult. One of the issues is shame. We don't want to talk about what's wrong, so we can't use that information to determine where we want to go. We make excuses -- customers will flee, people will sue, stock prices will go down -- even though we know that those excuses have been demonstrated to be false.
During the discussion, there was a lot of talk about the choice between informing users and bombarding them with information they can't understand. And lots more that I couldn't transcribe.
And that's it. SHB09 was a fantastic workshop, filled with interesting people and interesting discussion. Next year in the other Cambridge.
Ross Anderson and Adam Shostack wrote talk summaries, too. And Matt Blaze recorded audio:
There are thousands of comments -- many of them interesting -- on these topics on my blog. Search for the story you want to comment on, and join in.
Since 1998, CRYPTO-GRAM has been a free monthly newsletter providing summaries, analyses, insights, and commentaries on security: computer and otherwise. You can subscribe, unsubscribe, or change your address on the Web at <http://www.schneier.com/crypto-gram.html>. Back issues are also available at that URL.
Please feel free to forward CRYPTO-GRAM, in whole or in part, to colleagues and friends who will find it valuable. Permission is also granted to reprint CRYPTO-GRAM, as long as it is reprinted in its entirety.
CRYPTO-GRAM is written by Bruce Schneier. Schneier is the author of the best sellers "Schneier on Security," "Beyond Fear," "Secrets and Lies," and "Applied Cryptography," and an inventor of the Blowfish, Twofish, Phelix, and Skein algorithms. He is the Chief Security Technology Officer of BT BCSG, and is on the Board of Directors of the Electronic Privacy Information Center (EPIC). He is a frequent writer and lecturer on security topics. See <http://www.schneier.com>.
Crypto-Gram is a personal newsletter. Opinions expressed are not necessarily those of BT.
Copyright (c) 2009 by Bruce Schneier.
Photo of Bruce Schneier by Per Ervland.
Schneier on Security is a personal website. Opinions expressed are not necessarily those of Co3 Systems, Inc..