Entries Tagged "air travel"

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The TSA's Selective Laptop Ban

Last Monday, the TSA announced a peculiar new security measure to take effect within 96 hours. Passengers flying into the US on foreign airlines from eight Muslim countries would be prohibited from carrying aboard any electronics larger than a smartphone. They would have to be checked and put into the cargo hold. And now the UK is following suit.

It’s difficult to make sense of this as a security measure, particularly at a time when many people question the veracity of government orders, but other explanations are either unsatisfying or damning.

So let’s look at the security aspects of this first. Laptop computers aren’t inherently dangerous, but they’re convenient carrying boxes. This is why, in the past, TSA officials have demanded passengers turn their laptops on: to confirm that they’re actually laptops and not laptop cases emptied of their electronics and then filled with explosives.

Forcing a would-be bomber to put larger laptops in the plane’s hold is a reasonable defense against this threat, because it increases the complexity of the plot. Both the shoe-bomber Richard Reid and the underwear bomber Umar Farouk Abdulmutallab carried crude bombs aboard their planes with the plan to set them off manually once aloft. Setting off a bomb in checked baggage is more work, which is why we don’t see more midair explosions like Pan Am Flight 103 over Lockerbie, Scotland, in 1988.

Security measures that restrict what passengers can carry onto planes are not unprecedented either. Airport security regularly responds to both actual attacks and intelligence regarding future attacks. After the liquid bombers were captured in 2006, the British banned all carry-on luggage except passports and wallets. I remember talking with a friend who traveled home from London with his daughters in those early weeks of the ban. They reported that airport security officials confiscated every tube of lip balm they tried to hide.

Similarly, the US started checking shoes after Reid, installed full-body scanners after Abdulmutallab and restricted liquids in 2006. But all of those measures were global, and most lessened in severity as the threat diminished.

This current restriction implies some specific intelligence of a laptop-based plot and a temporary ban to address it. However, if that’s the case, why only certain non-US carriers? And why only certain airports? Terrorists are smart enough to put a laptop bomb in checked baggage from the Middle East to Europe and then carry it on from Europe to the US.

Why not require passengers to turn their laptops on as they go through security? That would be a more effective security measure than forcing them to check them in their luggage. And lastly, why is there a delay between the ban being announced and it taking effect?

Even more confusing, the New York Times reported that “officials called the directive an attempt to address gaps in foreign airport security, and said it was not based on any specific or credible threat of an imminent attack.” The Department of Homeland Security FAQ page makes this general statement, “Yes, intelligence is one aspect of every security-related decision,” but doesn’t provide a specific security threat. And yet a report from the UK states the ban “follows the receipt of specific intelligence reports.”

Of course, the details are all classified, which leaves all of us security experts scratching our heads. On the face of it, the ban makes little sense.

One analysis painted this as a protectionist measure targeted at the heavily subsidized Middle Eastern airlines by hitting them where it hurts the most: high-paying business class travelers who need their laptops with them on planes to get work done. That reasoning makes more sense than any security-related explanation, but doesn’t explain why the British extended the ban to UK carriers as well. Or why this measure won’t backfire when those Middle Eastern countries turn around and ban laptops on American carriers in retaliation. And one aviation official told CNN that an intelligence official informed him it was not a “political move.”

In the end, national security measures based on secret information require us to trust the government. That trust is at historic low levels right now, so people both in the US and other countries are rightly skeptical of the official unsatisfying explanations. The new laptop ban highlights this mistrust.

This essay previously appeared on CNN.com.

EDITED TO ADD: Here are two essays that look at the possible political motivations, and fallout, of this ban. And the EFF rightly points out that letting a laptop out of your hands and sight is itself a security risk—for the passenger.

EDITED TO ADD (4/12): This article suggests that the ban is because of a plot to hide explosives in iPads.

Posted on March 27, 2017 at 6:28 AMView Comments

Security Risks of TSA PreCheck

Former TSA Administrator Kip Hawley wrote an op-ed pointing out the security vulnerabilities in the TSA’s PreCheck program:

The first vulnerability in the system is its enrollment process, which seeks to verify an applicant’s identity. We know verification is a challenge: A 2011 Government Accountability Office report on TSA’s system for checking airport workers’ identities concluded that it was “not designed to provide reasonable assurance that only qualified applicants” got approved. It’s not a stretch to believe a reasonably competent terrorist could construct an identity that would pass PreCheck’s front end.

The other step in PreCheck’s “intelligence-driven, risk-based security strategy” is absurd on its face: The absence of negative information about a person doesn’t mean he or she is trustworthy. News reports are filled with stories of people who seemed to be perfectly normal right up to the moment they committed a heinous act. There is no screening algorithm and no database check that can accurately predict human behavior—especially on the scale of millions. It is axiomatic that terrorist organizations recruit operatives who have clean backgrounds and interview well.

None of this is news.

Back in 2004, I wrote:

Imagine you’re a terrorist plotter with half a dozen potential terrorists at your disposal. They all apply for a card, and three get one. Guess which are going on the mission? And they’ll buy round-trip tickets with credit cards and have a “normal” amount of luggage with them.

What the Trusted Traveler program does is create two different access paths into the airport: high security and low security. The intent is that only good guys will take the low-security path, and the bad guys will be forced to take the high-security path, but it rarely works out that way. You have to assume that the bad guys will find a way to take the low-security path.

The Trusted Traveler program is based on the dangerous myth that terrorists match a particular profile and that we can somehow pick terrorists out of a crowd if we only can identify everyone. That’s simply not true. Most of the 9/11 terrorists were unknown and not on any watch list. Timothy McVeigh was an upstanding US citizen before he blew up the Oklahoma City Federal Building. Palestinian suicide bombers in Israel are normal, nondescript people. Intelligence reports indicate that Al Qaeda is recruiting non-Arab terrorists for US operations.

I wrote much the same thing in 2007:

Background checks are based on the dangerous myth that we can somehow pick terrorists out of a crowd if we could identify everyone. Unfortunately, there isn’t any terrorist profile that prescreening can uncover. Timothy McVeigh could probably have gotten one of these cards. So could have Eric Rudolph, the pipe bomber at the 1996 Olympic Games in Atlanta. There isn’t even a good list of known terrorists to check people against; the government list used by the airlines has been the butt of jokes for years.

And have we forgotten how prevalent identity theft is these days? If you think having a criminal impersonating you to your bank is bad, wait until they start impersonating you to the Transportation Security Administration.

The truth is that whenever you create two paths through security—a high-security path and a low-security path—you have to assume that the bad guys will find a way to exploit the low-security path. It may be counterintuitive, but we are all safer if the people chosen for more thorough screening are truly random and not based on an error-filled database or a cursory background check.

In a companion blog post, Hawley has more details about why the program doesn’t work:

In the sense that PreCheck bars people who were identified by intelligence or law enforcement agencies as possible terrorists, then it was intelligence-driven. But using that standard for PreCheck is ridiculous since those people already get extra screening or are on the No-Fly list. The movie Patriots Day, out now, reminds us of the tragic and preventable Boston Marathon bombing. The FBI sent agents to talk to the Tsarnaev brothers and investigate them as possible terror suspects. And cleared them. Even they did not meet the “intelligence-driven” definition used in PreCheck.

The other problem with “intelligence-driven” in the PreCheck context is that intelligence actually tells us the opposite; specifically that terrorists pick clean operatives. If TSA uses current intelligence to evaluate risk, it would not be out enrolling everybody they can into pre-9/11 security for everybody not flagged by the security services.

Hawley and I may agree on the problem, but we have completely opposite solutions. The op-ed was too short to include details, but they’re in a companion blog post. Basically, he wants to screen PreCheck passengers more:

In the interests of space, I left out details of what I would suggest as short-and medium-term solutions. Here are a few ideas:

  • Immediately scrub the PreCheck enrollees for false identities. That can probably be accomplished best and most quickly by getting permission from members, and then using, commercial data. If the results show that PreCheck has already been penetrated, the program should be suspended.
  • Deploy K-9 teams at PreCheck lanes.
  • Use Behaviorally trained officers to interact with and check the credentials of PreCheck passengers.
  • Use Explosives Trace Detection cotton swabs on PreCheck passengers at a much higher rate. Same with removing shoes.
  • Turn on the body scanners and keep them fully utilized.
  • Allow liquids to stay in the carry-on since TSA scanners can detect threat liquids.
  • Work with the airlines to keep the PreCheck experience positive.
  • Work with airports to place PreCheck lanes away from regular checkpoints so as not to diminish lane capacity for non-PreCheck passengers. Rental Car check-in areas could be one alternative. Also, downtown check-in and screening (with secure transport to the airport) is a possibility.

These solutions completely ignore the data from the real-world experiment PreCheck has been. Hawley writes that PreCheck tells us that “terrorists pick clean operatives.” That’s exactly wrong. PreCheck tells us that, basically, there are no terrorists. If 1) it’s an easier way through airport security that terrorists will invariably use, and 2) there have been no instances of terrorists using it in the 10+ years it and its predecessors have been in operation, then the inescapable conclusion is that the threat is minimal. Instead of screening PreCheck passengers more, we should screen everybody else less. This is me in 2012: “I think the PreCheck level of airport screening is what everyone should get, and that the no-fly list and the photo ID check add nothing to security.”

I agree with Hawley that we need to overhaul airport security. Me in 2010: “Airport security is the last line of defense, and it’s not a very good one.” We need to recognize that the actual risk is much lower than we fear, and ratchet airport security down accordingly. And then we need to continue to invest in investigation and intelligence: security measures that work regardless of the tactic or target.

Posted on December 27, 2016 at 6:11 AMView Comments

Terrorist False Alarm at JFK Airport Demonstrates How Unprepared We Really Are

The detailed accounts of the terrorist-shooter false-alarm at Kennedy Airport in New York last week illustrate how completely and totally unprepared the airport authorities are for any real such event.

I have two reactions to this. On the one hand, this is a movie-plot threat—the sort of overly specific terrorist scenario that doesn’t make sense to defend against. On the other hand, police around the world need training in these types of scenarios in general. Panic can easily cause more deaths than terrorists themselves, and we need to think about what responsibilities police and other security guards have in these situations.

Posted on August 19, 2016 at 2:23 PMView Comments

Good Article on Airport Security

The New York Times wrote a good piece comparing airport security around the world, and pointing out that moving the security perimeter doesn’t make any difference if the attack can occur just outside the perimeter. Mark Stewart has the good quote:

“Perhaps the most cost-effective measure is policing and intelligence—to stop them before they reach the target,” Mr. Stewart said.

Sounds like something I would say.

Posted on July 6, 2016 at 9:45 AMView Comments

Security Analysis of TSA PreCheck

Interesting research: Mark G. Stewart and John Mueller, “Risk-based passenger screening: risk and economic assessment of TSA PreCheck increased security at reduced cost?

Executive Summary: The Transportation Security Administration’s PreCheck program is risk-based screening that allows passengers assessed as low risk to be directed to expedited, or PreCheck, screening. We begin by modelling the overall system of aviation security by considering all layers of security designed to deter or disrupt a terrorist plot to down an airliner with a passenger-borne bomb. Our analysis suggests that these measures reduce the risk of such an attack by at least 98%. Assuming that the accuracy of Secure Flight may be less than 100% when identifying low and high risk passengers, we then assess the effect of enhanced and expedited (or regular and PreCheck) screening on deterrence and disruption rates. We also evaluate programs that randomly redirect passengers from the PreCheck to the regular lines (random exclusion) and ones that redirect some passengers from regular to PreCheck lines (managed inclusion). We find that, if 50% of passengers are cleared for PreCheck, the additional risk reduction (benefit) due to PreCheck is 0.021% for attacks by lone wolves, and 0.056% for ones by terrorist organisations. If 75% of passengers rather than 50% go through PreCheck, these numbers are 0.017% and 0.044%, still providing a benefit in risk reduction. Under most realistic combinations of parameter values PreCheck actually increases risk reduction, perhaps up to 1%, while under the worst assumptions, it lowers risk reduction only by some 0.1%. Extensive sensitivity analyses suggests that, overall, PreCheck is most likely to have an increase in overall benefit.

The report also finds that adding random exclusion and managed inclusion to the PreCheck program has little effect on the risk reducing capability of PreCheck one way or the other. For example, if 10% of non-PreCheck passengers are randomly sent to the PreCheck line, the program still is delivers a benefit in risk reduction, and provides an additional savings for TSA of $11 million per year by reducing screening costs—while at the same time improving security outcomes.

There are also other co-benefits, and these are very substantial. Reducing checkpoint queuing times improves in the passenger experience, which would lead to higher airline revenues, can exceed several billion dollars per year. TSA PreCheck thus seems likely to bring considerable efficiencies to the screening process and great benefits to passengers, airports, and airlines while actually enhancing security a bit.

Posted on June 28, 2016 at 2:10 PMView Comments

Arresting People for Walking Away from Airport Security

A proposed law in Albany, NY, would make it a crime to walk away from airport screening.

Aside from wondering why county lawmakers are getting involved with what should be national policy, you have to ask: what are these people thinking?

They’re thinking in stories, of course. They have a movie plot in their heads, and they are imaging how this measure solves it.

The law is intended to cover what Apple described as a soft spot in the current system that allows passengers to walk away without boarding their flights if security staff flags them for additional scrutiny.

That could include would-be terrorists probing for weaknesses, Apple said, adding that his deputies currently have no legal grounds to question such a person.

Does anyone have any idea what stories these people have in their heads? What sorts of security weaknesses are exposed by walking up to airport security and then walking away?

Posted on May 31, 2016 at 6:35 AMView Comments

Detecting Explosives

Really interesting article on the difficulties involved with explosive detection at airport security checkpoints.

Abstract: The mid-air bombing of a Somali passenger jet in February was a wake-up call for security agencies and those working in the field of explosive detection. It was also a reminder that terrorist groups from Yemen to Syria to East Africa continue to explore innovative ways to get bombs onto passenger jets by trying to beat detection systems or recruit insiders. The layered state-of-the-art detection systems that are now in place at most airports in the developed world make it very hard for terrorists to sneak bombs onto planes, but the international aviation sector remains vulnerable because many airports in the developing world either have not deployed these technologies or have not provided rigorous training for operators. Technologies and security measures will need to improve to stay one step ahead of innovative terrorists. Given the pattern of recent Islamic State attacks, there is a strong argument for extending state-of-the-art explosive detection systems beyond the aviation sector to locations such as sports arenas and music venues.

I disagree with his conclusions—the last sentence above—but the technical information on explosives detection technology is really interesting.

Posted on May 20, 2016 at 2:06 PMView Comments

Economist Detained for Doing Math on an Airplane

An economics professor was detained when he was spotted doing math on an airplane:

On Thursday evening, a 40-year-old man ­—with dark, curly hair, olive skin and an exotic foreign accent—­ boarded a plane. It was a regional jet making a short, uneventful hop from Philadelphia to nearby Syracuse.

Or so dozens of unsuspecting passengers thought.

The curly-haired man tried to keep to himself, intently if inscrutably scribbling on a notepad he’d brought aboard. His seatmate, a blond-haired, 30-something woman sporting flip-flops and a red tote bag, looked him over. He was wearing navy Diesel jeans and a red Lacoste sweater—a look he would later describe as “simple elegance”—but something about him didn’t seem right to her.

She decided to try out some small talk.

Is Syracuse home? She asked.

No, he replied curtly.

He similarly deflected further questions. He appeared laser-focused ­—perhaps too laser-focused ­—on the task at hand, those strange scribblings.

Rebuffed, the woman began reading her book. Or pretending to read, anyway. Shortly after boarding had finished, she flagged down a flight attendant and handed that crew-member a note of her own.

This story ended better than some. Economics professor Guido Menzio (yes, he’s Italian) was taken off the plane, questioned, cleared, and allowed to board with the rest of his passengers two hours later.

This is a result of our stupid “see something, say something” culture. As I repeatedly say: “If you ask amateurs to act as front-line security personnel, you shouldn’t be surprised when you get amateur security.”

On the other hand, “Algebra, of course, does have Arabic origins plus math is used to make bombs.” Plus, this fine joke from 2003:

At Heathrow Airport today, an individual, later discovered to be a school teacher, was arrested trying to board a flight while in possession of a compass, a protractor, and a graphical calculator.

Authorities believe she is a member of the notorious al-Gebra movement. She is being charged with carrying weapons of math instruction.

AP story. Slashdot thread.

Seriously, though, I worry that this kind of thing will happen to me. I’m older, and I’m not very Semitic looking, but I am curt to my seatmates and intently focused on what I am doing—which sometimes involves looking at web pages about, and writing about, security and terrorism. I’m sure I’m vaguely suspicious.

EDITED TO ADD: Last month a student was removed from an airplane for speaking Arabic.

Posted on May 9, 2016 at 1:15 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.