Entries Tagged "false positives"

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Airport Behavioral Profiling Leads to an Arrest

I’m generally a fan of behavioral profiling. While it sounds weird and creepy and has been likened to Orwell’s “facecrime”, there’s no doubt that—when done properly—it works at catching common criminals:

On Dec. 4, Juan Carlos Berriel-Castillo, 22, and Bernardo Carmona-Olivares, 20, were planning to fly to Maui but were instead arrested on suspicion of forgery.

They tried to pass through a Terminal 4 security checkpoint with suspicious documents, Phoenix police spokeswoman Stacie Derge said.

The pair had false permanent-resident identification, and authorities also found false Social Security cards, officials say.

While the pair were questioned about the papers, a TSA official who had received behavior-recognition training observed a third man in the area who appeared to be connected to Berriel-Castillo and Carmona-Olivares, Melendez said.

As a result, police later arrested Samuel Gonzalez, 32. A background check revealed that Gonzalez was wanted on two misdemeanor warrants.

TSA press release here.

Security is a trade-off. The question is whether the expense of the Screening Passengers by Observation Techniques (SPOT) program, given the minor criminals it catches, is worth it. (Remember, it’s supposed to catch terrorists, not people with outstanding misdemeanor warrants.) Especially with the 99% false alarm rate:

Since January 2006, behavior-detection officers have referred about 70,000 people for secondary screening, Maccario said. Of those, about 600 to 700 were arrested on a variety of charges, including possession of drugs, weapons violations and outstanding warrants.

And the other social costs, including loss of liberty, restriction of fundamental freedoms, and the creation of a thoughtcrime. Is this the sort of power we want to give a police force in a constitutional democracy, or does it feel more like a police-state sort of thing?

This “Bizarro” cartoon sums it up nicely.

Posted on January 3, 2008 at 12:49 PMView Comments

Canadian Privacy Commissioner Comments on the No-Fly List

Refreshingly sensible:

Stoddart told inquiry Commissioner John Major she is concerned that people could be placed on the list in error and face dire consequences if their identities are then disclosed to the RCMP or passed on to police agencies in other countries.

And she questioned why, if people are so dangerous that they can’t get on a plane, they are deemed safe to travel by other means in Canada.

[…]

Between June 28, when the program came into effect, and the end of September, no passengers were turned away because of the list, the inquiry heard. Stoddart said that information only increases her suspicion about the value of the program.

“I think it only deepens the mystery of the rationale, the usefulness of this,” Stoddart said. “The program is totally opaque.”

Major suggested that perhaps less extreme measures could be taken. For example, individuals on the list might be able to undergo extra screening so they could be allowed to travel.

[…]

“We are looking to avoid what happened in 9/11. Presumably it’s to keep dangerous people capable of blowing planes up—or capturing them—off the plane. It seems difficult that you can do that by a name (on a list) alone.”

Other members of Stoddart’s staff added there are concerns someone could be stranded in Canada after arriving without incident, only to be prevented from boarding their return flight.

Posted on November 13, 2007 at 12:25 PMView Comments

Modern-Day Revenge

Mad at someone? Turn him in as a terrorist:

A man in Sweden who was angry with his daughter’s husband has been charged with libel for telling the FBI that the son-in-law had links to al-Qaeda, Swedish media reported on Friday.

The man, who admitted sending the email, said he did not think the US authorities would stupid enough to believe him.

The 40-year-old son-in-law and his wife were in the process of divorcing when the husband had to travel to the United States for business.

The wife didn’t want him to travel since she was sick and wanted him to help care for their children, regional daily Sydsvenska Dagbladet said without disclosing the couple’s names.

When the husband refused to stay home, his father-in-law wrote an email to the FBI saying the son-in-law had links to al-Qaeda in Sweden and that he was travelling to the US to meet his contacts.

He provided information on the flight number and date of arrival in the US.

The son-in-law was arrested upon landing in Florida. He was placed in handcuffs, interrogated and placed in a cell for 11 hours before being put on a flight back to Europe, the paper said.

EDITED TO ADD (11/6): Businesses do this too:

In May 2005 Jet’s application for a licence to fly to America was held up after a firm based in Maryland, also called Jet Airways, accused Mr Goyal’s company of being a money-laundering outfit for al-Qaeda. Mr Goyal says some of his local competitors were behind the claim, which was later withdrawn.

Posted on November 6, 2007 at 6:41 AMView Comments

The War on the Unexpected

We’ve opened up a new front on the war on terror. It’s an attack on the unique, the unorthodox, the unexpected; it’s a war on different. If you act different, you might find yourself investigated, questioned, and even arrested—even if you did nothing wrong, and had no intention of doing anything wrong. The problem is a combination of citizen informants and a CYA attitude among police that results in a knee-jerk escalation of reported threats.

This isn’t the way counterterrorism is supposed to work, but it’s happening everywhere. It’s a result of our relentless campaign to convince ordinary citizens that they’re the front line of terrorism defense. “If you see something, say something” is how the ads read in the New York City subways. “If you suspect something, report it” urges another ad campaign in Manchester, UK. The Michigan State Police have a seven-minute video. Administration officials from then-attorney general John Ashcroft to DHS Secretary Michael Chertoff to President Bush have asked us all to report any suspicious activity.

The problem is that ordinary citizens don’t know what a real terrorist threat looks like. They can’t tell the difference between a bomb and a tape dispenser, electronic name badge, CD player, bat detector, or trash sculpture; or the difference between terrorist plotters and imams, musicians, or architects. All they know is that something makes them uneasy, usually based on fear, media hype, or just something being different.

Even worse: after someone reports a “terrorist threat,” the whole system is biased towards escalation and CYA instead of a more realistic threat assessment.

Watch how it happens. Someone sees something, so he says something. The person he says it to—a policeman, a security guard, a flight attendant—now faces a choice: ignore or escalate. Even though he may believe that it’s a false alarm, it’s not in his best interests to dismiss the threat. If he’s wrong, it’ll cost him his career. But if he escalates, he’ll be praised for “doing his job” and the cost will be borne by others. So he escalates. And the person he escalates to also escalates, in a series of CYA decisions. And before we’re done, innocent people have been arrested, airports have been evacuated, and hundreds of police hours have been wasted.

This story has been repeated endlessly, both in the U.S. and in other countries. Someone—these are all real—notices a funny smell, or some white powder, or two people passing an envelope, or a dark-skinned man leaving boxes at the curb, or a cell phone in an airplane seat; the police cordon off the area, make arrests, and/or evacuate airplanes; and in the end the cause of the alarm is revealed as a pot of Thai chili sauce, or flour, or a utility bill, or an English professor recycling, or a cell phone in an airplane seat.

Of course, by then it’s too late for the authorities to admit that they made a mistake and overreacted, that a sane voice of reason at some level should have prevailed. What follows is the parade of police and elected officials praising each other for doing a great job, and prosecuting the poor victim—the person who was different in the first place—for having the temerity to try to trick them.

For some reason, governments are encouraging this kind of behavior. It’s not just the publicity campaigns asking people to come forward and snitch on their neighbors; they’re asking certain professions to pay particular attention: truckers to watch the highways, students to watch campuses, and scuba instructors to watch their students. The U.S. wanted meter readers and telephone repairmen to snoop around houses. There’s even a new law protecting people who turn in their travel mates based on some undefined “objectively reasonable suspicion,” whatever that is.

If you ask amateurs to act as front-line security personnel, you shouldn’t be surprised when you get amateur security.

We need to do two things. The first is to stop urging people to report their fears. People have always come forward to tell the police when they see something genuinely suspicious, and should continue to do so. But encouraging people to raise an alarm every time they’re spooked only squanders our security resources and makes no one safer.

We don’t want people to never report anything. A store clerk’s tip led to the unraveling of a plot to attack Fort Dix last May, and in March an alert Southern California woman foiled a kidnapping by calling the police about a suspicious man carting around a person-sized crate. But these incidents only reinforce the need to realistically assess, not automatically escalate, citizen tips. In criminal matters, law enforcement is experienced in separating legitimate tips from unsubstantiated fears, and allocating resources accordingly; we should expect no less from them when it comes to terrorism.

Equally important, politicians need to stop praising and promoting the officers who get it wrong. And everyone needs to stop castigating, and prosecuting, the victims just because they embarrassed the police by their innocence.

Causing a city-wide panic over blinking signs, a guy with a pellet gun, or stray backpacks, is not evidence of doing a good job: it’s evidence of squandering police resources. Even worse, it causes its own form of terror, and encourages people to be even more alarmist in the future. We need to spend our resources on things that actually make us safer, not on chasing down and trumpeting every paranoid threat anyone can come up with.

This essay originally appeared on Wired.com.

EDITED TO ADD (11/1): Some links didn’t make it into the original article. There’s this creepy “if you see a father holding his child’s hands, call the cops” campaign, this story of an iPod found on an airplane, and this story of an “improvised electronics device” trying to get through airport security. This is a good essay on the “war on electronics.”

EDITED TO ADD (11/25): More examples of rediculous non-terrorism overreactions, and a story about recruiting firefighters to snoop around in peoples’ houses:

Unlike police, firefighters and emergency medical personnel don’t need warrants to access hundreds of thousands of homes and buildings each year, putting them in a position to spot behavior that could indicate terrorist activity or planning.

Posted on November 1, 2007 at 4:42 AMView Comments

More Behavioral Profiling

I’ve seen several articles based on this press release:

Computer and behavioral scientists at the University at Buffalo are developing automated systems that track faces, voices, bodies and other biometrics against scientifically tested behavioral indicators to provide a numerical score of the likelihood that an individual may be about to commit a terrorist act.

I am generally in favor of funding all sorts of research, no matter how outlandish—you never know when you’ll discover something really good—and I am generally in favor of this sort of behavioral assessment profiling.

But I wish reporters would approach these topics with something resembling skepticism. The false-positive rate matters far more than the false-negative rate, and I doubt something like this will be ready for fielding any time soon.

EDITED TO ADD (10/13): Another comment.

Posted on October 15, 2007 at 6:16 AMView Comments

Fraudulent Amber Alerts

Amber Alerts are general notifications in the first few hours after a child has been abducted. The idea is that if you get the word out quickly, you have a better chance of recovering the child.

There’s an interesting social dynamic here, though. If you issue too many of these, the public starts ignoring them. This is doubly true if the alerts turn out to be false.

That’s why two hoax Amber Alerts in September (one in Miami and the other in North Carolina) are a big deal. And it’s a disturbing trend. Here’s data from 2004:

Out of 233 Amber Alerts issued last year, at least 46 were made for children who were lost, had run away or were the subjects of hoaxes and misunderstandings, according to the Scripps Howard study, which used records from the National Center for Missing and Exploited Children.

Police also violated federal and state guidelines by issuing dozens of vague alerts with little information upon which the public can act. The study found that 23 alerts were issued last year even though police didn’t know the name of the child who supposedly had been abducted. Twenty-five alerts were issued without complete details about the suspect or a description of the vehicle used in the abduction.

Think of it as a denial-of-service attack against the real world.

Posted on October 5, 2007 at 11:00 AMView Comments

Latest Terrorist False Alarm: Chili Peppers

In London:

Three streets were closed and people evacuated from the area as the search was carried out. After locating the source at about 7pm, emergency crews smashed their way into the Thai Cottage restaurant in D’Arblay Street only to emerge with a 9lb pot of smouldering dried chillies.

Baffled chef Chalemchai Tangjariyapoon, who had been cooking a spicy dip, was amazed to find himself at the centre of the terror scare.

“We only cook it once a year—it’s a spicy dip with extra hot chillies that are deliberately burned,” he said.

“To us it smells like burned chilli and it is slightly unusual. I can understand why people who weren’t Thai would not know what it was but it doesn’t smell like chemicals. I’m a bit confused.”

Another story.

Were this the U.S., that restaurant would be charged with terrorism, or creating a fake bomb, or anything to make the authorities feel better. On the other hand, at least the cook wasn’t shot.

EDITED TO ADD (10/4): Common sense:

The police spokesman said no arrests were made in the case.

“As far as I’m aware it’s not a criminal offense to cook very strong chili,” he said.

EDITED TO ADD (10/11): The BBC has a recipe, in case you need to create your own chemical weapon scare.

Posted on October 3, 2007 at 10:28 AMView Comments

Gun-Shaped Laptop Battery

Seems like bad design:

My laptop bag has scared TSA security personnel at several airports recently, requiring manual bag inspections each time. And when it happened again this week I finally figured out what it is that was freaking them out when the bag went through the x-ray machine—it’s the spare laptop battery I always carry. This would never be an issue if the battery were inside the laptop, but the spare battery (depending on how it is laying in the back) can catch attention. But, TSA issues aside, look at the shape of the battery. You just have to wonder—what on earth was IBM thinking?

The answer, of course, is obvious: it never occured to them.

Posted on August 8, 2007 at 2:12 PMView Comments

Another Biometric: Vein Patterns

Interesting:

In fact, vein recognition technology has one fundamental advantage over finger print systems: vein patterns in fingers and palms are biometric characteristics that are not left behind unintentionally in every-day activities. In tests conducted by heise, even extreme close-ups of a palm taken with a digital camera, whose RAW format can be filtered systematically to emphasize the near-infrared range, were unable to deliver a clear reproduction of the line pattern. With the transluminance method used by Hitachi it is practically impossible to read out the pattern unnoticed with today’s technology. Another side effect of near-infrared imaging also has relevance to security: vein patterns of inanimate bodily parts become useless after few minutes, due to the increasing deoxidisation of the tissue.

Even if someone manages to obtain a person’s vein pattern, there is no known method for creating a functioning dummy, as is the case for finger prints, where this can be achieved even with home-made tools, as demonstrated by the german computer magazine c’t. As in the case with vendors of finger print systems, Hitachi and Fujitsu do not disclose information on liveness detection methods used in their products.

Besides the considerably improved forgery protection, the vendors of vein recognition technology claim further advantages. Compared to finger print sensors, vein recognition systems are said to deliver false rejection rates (FRR) two orders below that of finger print systems when operating at a comparable false acceptance rate (FAR). This can be ascribed to the basic structure of vein patterns having a much higher degree of variability than finger prints.

This is all interesting. I don’t know about the details of the technology, but the discussions of false positives, false negatives, and forgeability are the right ones to have. Remember, though, that while biometrics are an effective security technology, they’re not a panacea.

Posted on August 8, 2007 at 7:02 AMView Comments

Terrorist Watch List: 20,000 False Alarms

Why does anyone think this makes security sense?

The Justice Department’s proposed budget for 2008 reveals for the first time how often names match against the database, reporting that there were 19,967 “positive matches” in 2006. The TSC had expected to match a far fewer number 14,780. The watch list matched people 5,396 and 15,730 times in 2004 and 2005 respectively.

The report defines a positive match as “one in which an encountered individual is positively matched with an identity in the Terrorist Screening Data Base, or TSDB.”

It’s not clear from the report whether those numbers include individuals whose names only coincidently match one of those on list, such as when Sen. Ted Kennedy was confused with a former IRA terrorist also named Kennedy.

The watch list has been hounded by these mismatches, which have included small children, former presidential candidates, and Americans with common names such as David Nelson.

How do I know they’re all false alarms? Because this administration makes a press splash with every arrest, no matter how scant the evidence is. Do you really think they would pass up a chance to tout how good the watch list is?

EDITED TO ADD (8/28): The Washington Post just got around to writing an article on the topic, and Dan Solove has some good commentary.

Posted on July 23, 2007 at 1:39 PMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.