Entries Tagged "risk assessment"

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Airport Passenger Screening

It seems like every time someone tests airport security, airport security fails. In tests between November 2001 and February 2002, screeners missed 70 percent of knives, 30 percent of guns and 60 percent of (fake) bombs. And recently (see also this), testers were able to smuggle bomb-making parts through airport security in 21 of 21 attempts. It makes you wonder why we’re all putting our laptops in a separate bin and taking off our shoes. (Although we should all be glad that Richard Reid wasn’t the “underwear bomber.”)

The failure to detect bomb-making parts is easier to understand. Break up something into small enough parts, and it’s going to slip past the screeners pretty easily. The explosive material won’t show up on the metal detector, and the associated electronics can look benign when disassembled. This isn’t even a new problem. It’s widely believed that the Chechen women who blew up the two Russian planes in August 2004 probably smuggled their bombs aboard the planes in pieces.

But guns and knives? That surprises most people.

Airport screeners have a difficult job, primarily because the human brain isn’t naturally adapted to the task. We’re wired for visual pattern matching, and are great at picking out something we know to look for — for example, a lion in a sea of tall grass.

But we’re much less adept at detecting random exceptions in uniform data. Faced with an endless stream of identical objects, the brain quickly concludes that everything is identical and there’s no point in paying attention. By the time the exception comes around, the brain simply doesn’t notice it. This psychological phenomenon isn’t just a problem in airport screening: It’s been identified in inspections of all kinds, and is why casinos move their dealers around so often. The tasks are simply mind-numbing.

To make matters worse, the smuggler can try to exploit the system. He can position the weapons in his baggage just so. He can try to disguise them by adding other metal items to distract the screeners. He can disassemble bomb parts so they look nothing like bombs. Against a bored screener, he has the upper hand.

And, as has been pointed out again and again in essays on the ludicrousness of post-9/11 airport security, improvised weapons are a huge problem. A rock, a battery for a laptop, a belt, the extension handle off a wheeled suitcase, fishing line, the bare hands of someone who knows karate … the list goes on and on.

Technology can help. X-ray machines already randomly insert “test” bags into the stream — keeping screeners more alert. Computer-enhanced displays are making it easier for screeners to find contraband items in luggage, and eventually the computers will be able to do most of the work. It makes sense: Computers excel at boring repetitive tasks. They should do the quick sort, and let the screeners deal with the exceptions.

Sure, there’ll be a lot of false alarms, and some bad things will still get through. But it’s better than the alternative.

And it’s likely good enough. Remember the point of passenger screening. We’re not trying to catch the clever, organized, well-funded terrorists. We’re trying to catch the amateurs and the incompetent. We’re trying to catch the unstable. We’re trying to catch the copycats. These are all legitimate threats, and we’re smart to defend against them. Against the professionals, we’re just trying to add enough uncertainty into the system that they’ll choose other targets instead.

The terrorists’ goals have nothing to do with airplanes; their goals are to cause terror. Blowing up an airplane is just a particular attack designed to achieve that goal. Airplanes deserve some additional security because they have catastrophic failure properties: If there’s even a small explosion, everyone on the plane dies. But there’s a diminishing return on investments in airplane security. If the terrorists switch targets from airplanes to shopping malls, we haven’t really solved the problem.

What that means is that a basic cursory screening is good enough. If I were investing in security, I would fund significant research into computer-assisted screening equipment for both checked and carry-on bags, but wouldn’t spend a lot of money on invasive screening procedures and secondary screening. I would much rather have well-trained security personnel wandering around the airport, both in and out of uniform, looking for suspicious actions.

When I travel in Europe, I never have to take my laptop out of its case or my shoes off my feet. Those governments have had far more experience with terrorism than the U.S. government, and they know when passenger screening has reached the point of diminishing returns. (They also implemented checked-baggage security measures decades before the United States did — again recognizing the real threat.)

And if I were investing in security, I would invest in intelligence and investigation. The best time to combat terrorism is before the terrorist tries to get on an airplane. The best countermeasures have value regardless of the nature of the terrorist plot or the particular terrorist target.

In some ways, if we’re relying on airport screeners to prevent terrorism, it’s already too late. After all, we can’t keep weapons out of prisons. How can we ever hope to keep them out of airports?

A version of this essay originally appeared on Wired.com.

Posted on March 23, 2006 at 7:03 AMView Comments

Ben Franklin on the Feeling of Security

Today is Ben Franklin’s 300th birthday. Among many other discoveries and inventions, Franklin worked out a way of protecting buildings from lightning strikes, by providing a conducting path to ground — outside a building — from one or more pointed rods high atop the structure. People tried this, and it worked. Franklin became a celebrity, not just among “electricians,” but among the general public.

An article in this month’s issue of Physics Today has a great 1769 quote by Franklin about lightning rods, and the reality vs. the feeling of security:

Those who calculate chances may perhaps find that not one death (or the destruction of one house) in a hundred thousand happens from that cause, and that therefore it is scarce worth while to be at any expense to guard against it. But in all countries there are particular situations of buildings more exposed than others to such accidents, and there are minds so strongly impressed with the apprehension of them, as to be very unhappy every time a little thunder is within their hearing; it may therefore be well to render this little piece of new knowledge as general and well understood as possible, since to make us safe is not all its advantage, it is some to make us easy. And as the stroke it secures us from might have chanced perhaps but once in our lives, while it may relieve us a hundred times from those painful apprehensions, the latter may possibly on the whole contribute more to the happiness of mankind than the former.

Posted on January 17, 2006 at 7:52 AMView Comments

Today's Movie-Plot Threat: Electronic Pulses from Space

No. Really:

The United States is highly vulnerable to attack from electronic pulses caused by a nuclear blast in space, according to a new book on threats to U.S. security.

A single nuclear weapon carried by a ballistic missile and detonated a few hundred miles over the United States would cause “catastrophe for the nation” by damaging electricity-based networks and infrastructure, including computers and telecommunications, according to “War Footing: 10 Steps America Must Take to Prevail in the War for the Free World.”

“This is the single most serious national-security challenge and certainly the least known,” said Frank J. Gaffney Jr. of the Center for Security Policy, a former Pentagon official and lead author of the book, which includes contributions by 34 security and intelligence specialists.

The “single most serious national-security challenge.” Absolutely nothing more serious.

Sheesh.

Posted on November 23, 2005 at 7:39 AMView Comments

Convicted Felons with Big Dogs

Here’s a security threat I’ll bet you never even considered before: convicted felons with large dogs:

The Contra Costa County board of supervisors [in California] unanimously supported on Tuesday prohibiting convicted felons from owning any dog that is aggressive or weighs more than 20 pounds, making it all but certain the proposal will become law when it formally comes before the board for approval Nov. 15.

These are not felons in jail. These are felons who have been released from jail after serving their time. They’re allowed to re-enter society, but letting them own a large dog would be just too much of a risk to the community?

Posted on October 28, 2005 at 12:17 PMView Comments

Research in Behavioral Risk Analysis

I very am interested in this kind of research:

Network Structure, Behavioral Considerations and Risk Management in Interdependent Security Games

Interdependent security (IDS) games model situations where each player has to determine whether or not to invest in protection or security against an uncertain event knowing that there is some chance s/he will be negatively impacted by others who do not follow suit. IDS games capture a wide variety of collective risk and decision-making problems that include airline security, corporate governance, computer network security and vaccinations against diseases. This research project will investigate the marriage of IDS models with network formation models developed from social network theory and apply these models to problems in network security. Behavioral and controlled experiments will examine how human participants actually make choices under uncertainty in IDS settings. Computational aspects of IDS models will also be examined. To encourage and induce individuals to invest in cost-effective protection measures for IDS problems, we will examine several risk management strategies designed to foster cooperative behavior that include providing risk information, communication with others, economic incentives, and tipping strategies.

The proposed research is interdisciplinary in nature and should serve as an exciting focal point for researchers in computer science, decision and management sciences, economics, psychology, risk management, and policy analysis. It promises to advance our understanding of decision-making under risk and uncertainty for problems that are commonly faced by individuals, organizations, and nations. Through advances in computational methods one should be able to apply IDS models to large-scale problems. The research will also focus on weak links in an interdependent system and suggest risk management strategies for reducing individual and societal losses in the interconnected world in which we live.

Posted on September 15, 2005 at 7:05 AMView Comments

Talking to Strangers

In Beyond Fear I wrote: “Many children are taught never to talk to strangers, an extreme precaution with minimal security benefit.”

In talks, I’m even more direct. I think “don’t talk to strangers” is just about the worst possible advice you can give a child. Most people are friendly and helpful, and if a child is in distress, asking the help of a stranger is probably the best possible thing he can do.

This advice would have helped Brennan Hawkins, the 11-year-old boy who was lost in the Utah wilderness for four days.

The parents said Brennan had seen people searching for him on horse and ATV, but avoided them because of what he had been taught.

“He stayed on the trail, he avoided strangers,” Jody Hawkins said. “His biggest fear, he told me, was that someone would steal him.”

They said they hadn’t talked to Brennan and his four siblings about what they should do about strangers if they were lost. “This may have come to a faster conclusion had we discussed that,” Toby Hawkins said.

In a world where good guys are common and bad guys are rare, assuming a random person is a good guy is a smart security strategy. We need to help children develop their natural intuition about risk, and not give them overbroad rules.

Also in Beyond Fear, I wrote:

As both individuals and a society, we can make choices about our security. We can choose more security or less security. We can choose greater impositions on our lives and freedoms, or fewer impositions. We can choose the types of risks and security solutions we’re willing to tolerate and decide that others are unacceptable.

As individuals, we can decide to buy a home alarm system to make ourselves more secure, or we can save the money because we don’t consider the added security to be worth it. We can decide not to travel because we fear terrorism, or we can decide to see the world because the world is wonderful. We can fear strangers because they might be attackers, or we can talk to strangers because they might become friends.

Posted on June 23, 2005 at 2:40 PMView Comments

Security Trade-Offs

An essay by an anonymous CSO. This is how it begins:

On any given day, we CSOs come to work facing a multitude of security risks. They range from a sophisticated hacker breaching the network to a common thug picking a lock on the loading dock and making off with company property. Each of these scenarios has a probability of occurring and a payout (in this case, a cost to the company) should it actually occur. To guard against these risks, we have a finite budget of resources in the way of time, personnel, money and equipment—poker chips, if you will.

If we’re good gamblers, we put those chips where there is the highest probability of winning a high payout. In other words, we guard against risks that are most likely to occur and that, if they do occur, will cost the company the most money. We could always be better, but as CSOs, I think we’re getting pretty good at this process. So lately I’ve been wondering—as I watch spending on national security continue to skyrocket, with diminishing marginal returns—why we as a nation can’t apply this same logic to national security spending. If we did this, the war on terrorism would look a lot different. In fact, it might even be over.

The whole thing is worth reading.

Posted on April 22, 2005 at 12:32 PMView Comments

Destroying the Earth

This is a fascinating — and detailed — analysis of what would be required to destroy the earth: materials, methods, feasibility, schedule. While the DHS might view this as a terrorist manual and get it removed from the Internet, the good news is that obliterating the planet isn’t an easy task.

Posted on March 15, 2005 at 5:30 PMView Comments

Linux Security

I’m a big fan of the Honeynet Project (and a member of their board of directors). They don’t have a security product; they do security research. Basically, they wire computers up with sensors, put them on the Internet, and watch hackers attack them.

They just released a report about the security of Linux:

Recent data from our honeynet sensor grid reveals that the average life expectancy to compromise for an unpatched Linux system has increased from 72 hours to 3 months. This means that a unpatched Linux system with commonly used configurations (such as server builds of RedHat 9.0 or Suse 6.2) have an online mean life expectancy of 3 months before being successfully compromised.

This is much greater than that of Windows systems, which have average life expectancies on the order of a few minutes.

It’s also important to remember that this paper focuses on vulnerable systems. The Honeynet researchers deployed almost 20 vulnerable systems to monitor hacker tactics, and found that no one was hacking the systems. That’s the real story: the hackers aren’t bothering with Linux. Two years ago, a vulnerable Linux system would be hacked in less than three days; now it takes three months.

Why? My guess is a combination of two reasons. One, Linux is that much more secure than Windows. Two, the bad guys are focusing on Windows — more bang for the buck.

See also here and here.

Posted on January 6, 2005 at 1:45 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.