Entries Tagged "false positives"

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Automated Targeting System

If you’ve traveled abroad recently, you’ve been investigated. You’ve been assigned a score indicating what kind of terrorist threat you pose. That score is used by the government to determine the treatment you receive when you return to the U.S. and for other purposes as well.

Curious about your score? You can’t see it. Interested in what information was used? You can’t know that. Want to clear your name if you’ve been wrongly categorized? You can’t challenge it. Want to know what kind of rules the computer is using to judge you? That’s secret, too. So is when and how the score will be used.

U.S. customs agencies have been quietly operating this system for several years. Called Automated Targeting System, it assigns a “risk assessment” score to people entering or leaving the country, or engaging in import or export activity. This score, and the information used to derive it, can be shared with federal, state, local and even foreign governments. It can be used if you apply for a government job, grant, license, contract or other benefit. It can be shared with nongovernmental organizations and individuals in the course of an investigation. In some circumstances private contractors can get it, even those outside the country. And it will be saved for 40 years.

Little is known about this program. Its bare outlines were disclosed in the Federal Register in October. We do know that the score is partially based on details of your flight record—where you’re from, how you bought your ticket, where you’re sitting, any special meal requests—or on motor vehicle records, as well as on information from crime, watch-list and other databases.

Civil liberties groups have called the program Kafkaesque. But I have an even bigger problem with it. It’s a waste of money.

The idea of feeding a limited set of characteristics into a computer, which then somehow divines a person’s terrorist leanings, is farcical. Uncovering terrorist plots requires intelligence and investigation, not large-scale processing of everyone.

Additionally, any system like this will generate so many false alarms as to be completely unusable. In 2005 Customs & Border Protection processed 431 million people. Assuming an unrealistic model that identifies terrorists (and innocents) with 99.9% accuracy, that’s still 431,000 false alarms annually.

The number of false alarms will be much higher than that. The no-fly list is filled with inaccuracies; we’ve all read about innocent people named David Nelson who can’t fly without hours-long harassment. Airline data, too, are riddled with errors.

The odds of this program’s being implemented securely, with adequate privacy protections, are not good. Last year I participated in a government working group to assess the security and privacy of a similar program developed by the Transportation Security Administration, called Secure Flight. After five years and $100 million spent, the program still can’t achieve the simple task of matching airline passengers against terrorist watch lists.

In 2002 we learned about yet another program, called Total Information Awareness, for which the government would collect information on every American and assign him or her a terrorist risk score. Congress found the idea so abhorrent that it halted funding for the program. Two years ago, and again this year, Secure Flight was also banned by Congress until it could pass a series of tests for accuracy and privacy protection.

In fact, the Automated Targeting System is arguably illegal, as well (a point several congressmen made recently); all recent Department of Homeland Security appropriations bills specifically prohibit the department from using profiling systems against persons not on a watch list.

There is something un-American about a government program that uses secret criteria to collect dossiers on innocent people and shares that information with various agencies, all without any oversight. It’s the sort of thing you’d expect from the former Soviet Union or East Germany or China. And it doesn’t make us any safer from terrorism.

This essay, without the links, was published in Forbes. They also published a rebuttal by William Baldwin, although it doesn’t seen to rebut any of the actual points.

Here’s an odd division of labor: a corporate data consultant argues for more openness, while a journalist favors more secrecy.

It’s only odd if you don’t understand security.

Posted on December 22, 2006 at 11:38 AM • View Comments

Microsoft Anti-Phishing and Small Businesses

Microsoft has a new anti-phishing service in Internet Explorer 7 that will turn the address bar green and display the website owner’s identity when surfers visit on-line merchants previously approved as legitimate. So far, so good. But the service is only available to corporations: not to sole proprietorships, partnerships, or individuals.

Of course, if a merchant’s bar doesn’t turn green it doesn’t mean that they’re bad. It’ll be white, which indicates “no information.” There are also yellow and red indications, corresponding to “suspicious” and “known fraudulent site.” But small businesses are worried that customers will be afraid to buy from non-green sites.

That’s possible, but it’s more likely that users will learn that the marker isn’t reliable and start to ignore it.

Any white-list system like this has two sources of error. False positives, where phishers get the marker. And false negatives, where legitimate honest merchants don’t. Any system like this has to effectively deal with both.

EDITED TO ADD (12/21): Research paper: “Phinding Phish: An Evaulation of Anti-Phishing Toolbars,” by L. Cranor, S. Egleman, J. Hong, and Y. Zhang.

Posted on December 21, 2006 at 6:58 AM • View Comments

Forecasting Murderers

There’s new software that can predict who is likely to become a murderer.

Using probation department cases entered into the system between 2002 and 2004, Berk and his colleagues performed a two-year follow-up study—enough time, they theorized, for a person to reoffend if he was going to. They tracked each individual, with particular attention to the people who went on to kill. That created the model. What remains at this stage is to find a way to marry the software to the probation department’s information technology system.

When caseworkers begin applying the model next year they will input data about their individual cases – what Berk calls “dropping ‘Joe’ down the model”—to come up with scores that will allow the caseworkers to assign the most intense supervision to the riskiest cases.

Even a crime as serious as aggravated assault—pistol whipping, for example—”might not mean that much” if the first-time offender is 30, but it is an “alarming indicator” in a first-time offender who is 18, Berk said.

The model was built using adult probation data stripped of personal identifying information for confidentiality. Berk thinks it could be an even more powerful diagnostic tool if he could have access to similarly anonymous juvenile records.

The central public policy question in all of this is a resource allocation problem. With not enough resources to go around, overloaded case workers have to cull their cases to find the ones in most urgent need of attention—the so-called true positives, as epidemiologists say.

But before that can begin in earnest, the public has to decide how many false positives it can afford in order to head off future killers, and how many false negatives (seemingly nonviolent people who nevertheless go on to kill) it is willing to risk to narrow the false positive pool.

Pretty scary stuff, as it gets into the realm of thoughtcrime.

Posted on December 1, 2006 at 7:34 AM • View Comments

Paramedic Stopped at Airport Security for Nitroglycerine Residue

At least we know those chemical-residue detectors are working:

The punch line is that my bag tested positive for nitroglycerine residue. Which is, in hindsight, totally not unexpected, since it has been home to several bottles of nitro spray that at one point or another have found their way into my pockets and then into my bag. (Don’t look at me like that—I’m not stealing the damn drug. It’s just that it’s frequently easier to shove them in a pants pocket rather than keep fishing for one at the bedside or whatever, and besides, we’ve now gone to single-patient use sprays so that once you use one on one patient, it’s fininshed.) Whether one discharged, or leaked, or whatevered in my bag, it somehow got NTG molecules all over the place, and that’s what the detector picked up. The guy said this happens all the time but I’m not so sure, and in any event I’m not even remotely certain how I could go about getting the NTG residue off my bag so this doesn’t happen in the future. NTG spray has a pretty distinctive smell. All I can smell in my bag is consumer electronics, so it must have been some minute amount somewhere.

Posted on October 25, 2006 at 8:59 AM • View Comments

Please Stop My Car

Residents of Prescott Valley are being invited to register their car if they don’t drive in the middle of the night. Police will then stop those cars if they are on the road at that time, under the assumption that they’re stolen.

The Watch Your Car decal program is a voluntary program whereby vehicle owners enroll their vehicles with the AATA. The vehicle is then entered into a special database, developed and maintained by the AATA, which is directly linked to the Motor Vehicle Division (MVD).

Participants then display the Watch Your Car decals in the front and rear windows of their vehicle. By displaying the decals, vehicle owners convey to law enforcement officials that their vehicle is not usually in use between the hours of 1:00 AM and 5:00 AM, when the majority of thefts occur.

If a police officer witnesses the vehicle in operation between these hours, they have the authority to pull it over and question the driver. With access to the MVD database, the officer will be able to determine if the vehicle has been stolen, or not. The program also allows law enforcement officials to notify the vehicle’s owner immediately upon determination that it is being illegally operated.

This program is entirely optional, but there’s a serious externality. If the police spend time chasing false alarms, they’re not available for other police business. If the town charged car owners a fine for each false alarm, I would have no problems with this program. It doesn’t have to be a large fine, but it has to be enough to offset the cost to the town. It’s no different than police departments charging homeowners for false burglar alarms, when the alarm systems are automatically hooked into the police stations.

Posted on October 16, 2006 at 6:30 AM • View Comments

This Is What Vigilantism Looks Like

Another airplane passenger false alarm:

Seth Stein is used to jetting around the world to create stylish holiday homes for wealthy clients. This means the hip architect is familiar with the irritations of heightened airline security post-9/11. But not even he could have imagined being mistaken for an Islamist terrorist and physically pinned to his seat while aboard an American Airlines flight—especially as he has Jewish origins.

Turns out that one of the other passengers decided to take matters into his own hands.

In Mr Stein’s case, he was pounced on as the crew and other travellers looked on. The drama unfolded less than an hour into the flight. As he settled down with a book and a ginger ale, the father-of-three was grabbed from behind and held in a head-lock.

“This guy just told me his name was Michael Wilk, that he was with the New York Police Department, that I’d been acting suspiciously and should stay calm. I could barely find my voice and couldn’t believe it was happening,” said Mr Stein.

“He went into my pocket and took out my passport and my iPod. All the other passengers were looking concerned.” Eventually, cabin crew explained that the captain had run a security check on Mr Stein after being alerted by the policeman and that this had cleared him. The passenger had been asked to go back to his seat before he had restrained Mr Stein. When the plane arrived in New York, Mr Stein was met by apologetic police officers who offered to fast-track him out of the airport.

Even stranger:

In a twist to the story, Mr Stein has since discovered that there is only one Michael Wilk on the NYPD’s official register of officers, but the man retired 25 years ago. Officials have told the architect that his assailant may work for another law enforcement agency but have refused to say which one.

I’ve written about this kind of thing before.

EDITED TO ADD (10/3): Here’s a man booted off a plane for speaking Tamil into his cellphone.

Posted on October 3, 2006 at 12:42 PM • View Comments

Faulty Data and the Arar Case

Maher Arar is a Syrian-born Canadian citizen. On September 26, 2002, he tried to fly from Switzerland to Toronto. Changing planes in New York, he was detained by the U.S. authorities, and eventually shipped to Syria where he was tortured. He’s 100% innocent. (Background here.)

The Canadian government has completed its “Commission of Inquiry into the Actions of Canadian Officials in Relation to Maher Arar,” the results of which are public. From their press release:

On Maher Arar, the Commissioner comes to one important conclusion: “I am able to say categorically that there is no evidence to indicate that Mr. Arar has committed any offence or that his activities constitute a threat to the security of Canada.”

Certainly something that everyone who supports the U.S.’s right to detain and torture people without having to demonstrate their guilt should think about. But what’s more interesting to readers of this blog is the role that inaccurate data played in the deportation and ultimately torture of an innocent man.

Privacy International summarizes the report. These are among their bullet points:

  • The RCMP provided the U.S. with an entire database of information relating to a terrorism investigation (three CDs of information), in a way that did not comply with RCMP policies that require screening for relevance, reliability, and personal information. In fact, this action was without precedent.
  • The RCMP provided the U.S. with inaccurate information about Arar that portrayed him in an infairly negative fashion and overstated his importance to a RCMP investigation. They included some “erroneous notes.”
  • While he was detained in the U.S., the RCMP provided information regarding him to the U.S. Federal Bureau of Investigation (FBI), “some of which portrayed him in an inaccurate and unfair way.” The RCMP provided inaccurate information to the U.S. authorities that tended to link Arar to other terrorist suspects; and told the U.S. authorities that Arar had previously refused to be interviewed, which was also incorrect; and the RCMP also said that soon after refusing the interview he suddenly left Canada for Tunisia. “The statement about the refusal to be interviewed had the potential to arouse suspicion, especially among law enforcement officers, that Mr. Arar had something to hide.” The RCMP’s information to the U.S. authorities also placed Arar in the vicinity of Washington DC on September 11, 2001 when he was instead in California.

Judicial oversight is a security mechanism. It prevents the police from incarcerating the wrong person. The point of habeas corpus is that the police need to present their evidence in front of a neutral third party, and not indefinitely detain or torture people just because they believe they’re guilty. We are all less secure if we water down these security measures.

Posted on September 29, 2006 at 7:06 AM • View Comments

Burglars Foil Alarm Systems

Clever trick:

Their scheme: Cut a closed store’s phone lines. Hang back while cops respond to the alarm. After officers fail to spot anything wrong and drive away, break into the store and spend as much time as they need to make off with a weekend’s worth of cash.

And one I wrote about in Beyond Fear (page 56):

Attackers commonly force active failures specifically to cause a larger system to fail. Burglars cut an alarm wire at a warehouse and then retreat a safe distance. The police arrive and find nothing, decide that it’s an active failure, and tell the warehouse owner to deal with it in the morning. Then, after the police leave, the burglars reappear and steal everything.

Posted on September 13, 2006 at 11:10 AM • View Comments

What the Terrorists Want

On Aug. 16, two men were escorted off a plane headed for Manchester, England, because some passengers thought they looked either Asian or Middle Eastern, might have been talking Arabic, wore leather jackets, and looked at their watches—and the passengers refused to fly with them on board. The men were questioned for several hours and then released.

On Aug. 15, an entire airport terminal was evacuated because someone’s cosmetics triggered a false positive for explosives. The same day, a Muslim man was removed from an airplane in Denver for reciting prayers. The Transportation Security Administration decided that the flight crew overreacted, but he still had to spend the night in Denver before flying home the next day. The next day, a Port of Seattle terminal was evacuated because a couple of dogs gave a false alarm for explosives.

On Aug. 19, a plane made an emergency landing in Tampa, Florida, after the crew became suspicious because two of the lavatory doors were locked. The plane was searched, but nothing was found. Meanwhile, a man who tampered with a bathroom smoke detector on a flight to San Antonio was cleared of terrorism, but only after having his house searched.

On Aug. 16, a woman suffered a panic attack and became violent on a flight from London to Washington, so the plane was escorted to the Boston airport by fighter jets. “The woman was carrying hand cream and matches but was not a terrorist threat,” said the TSA spokesman after the incident.

And on Aug. 18, a plane flying from London to Egypt made an emergency landing in Italy when someone found a bomb threat scrawled on an air sickness bag. Nothing was found on the plane, and no one knows how long the note was on board.

I’d like everyone to take a deep breath and listen for a minute.

The point of terrorism is to cause terror, sometimes to further a political goal and sometimes out of sheer hatred. The people terrorists kill are not the targets; they are collateral damage. And blowing up planes, trains, markets or buses is not the goal; those are just tactics. The real targets of terrorism are the rest of us: the billions of us who are not killed but are terrorized because of the killing. The real point of terrorism is not the act itself, but our reaction to the act.

And we’re doing exactly what the terrorists want.

We’re all a little jumpy after the recent arrest of 23 terror suspects in Great Britain. The men were reportedly plotting a liquid-explosive attack on airplanes, and both the press and politicians have been trumpeting the story ever since.

In truth, it’s doubtful that their plan would have succeeded; chemists have been debunking the idea since it became public. Certainly the suspects were a long way off from trying: None had bought airline tickets, and some didn’t even have passports.

Regardless of the threat, from the would-be bombers’ perspective, the explosives and planes were merely tactics. Their goal was to cause terror, and in that they’ve succeeded.

Imagine for a moment what would have happened if they had blown up 10 planes. There would be canceled flights, chaos at airports, bans on carry-on luggage, world leaders talking tough new security measures, political posturing and all sorts of false alarms as jittery people panicked. To a lesser degree, that’s basically what’s happening right now.

Our politicians help the terrorists every time they use fear as a campaign tactic. The press helps every time it writes scare stories about the plot and the threat. And if we’re terrified, and we share that fear, we help. All of these actions intensify and repeat the terrorists’ actions, and increase the effects of their terror.

(I am not saying that the politicians and press are terrorists, or that they share any of the blame for terrorist attacks. I’m not that stupid. But the subject of terrorism is more complex than it appears, and understanding its various causes and effects are vital for understanding how to best deal with it.)

The implausible plots and false alarms actually hurt us in two ways. Not only do they increase the level of fear, but they also waste time and resources that could be better spent fighting the real threats and increasing actual security. I’ll bet the terrorists are laughing at us.

Another thought experiment: Imagine for a moment that the British government arrested the 23 suspects without fanfare. Imagine that the TSA and its European counterparts didn’t engage in pointless airline-security measures like banning liquids. And imagine that the press didn’t write about it endlessly, and that the politicians didn’t use the event to remind us all how scared we should be. If we’d reacted that way, then the terrorists would have truly failed.

It’s time we calm down and fight terror with antiterror. This does not mean that we simply roll over and accept terrorism. There are things our government can and should do to fight terrorism, most of them involving intelligence and investigation—and not focusing on specific plots.

But our job is to remain steadfast in the face of terror, to refuse to be terrorized. Our job is to not panic every time two Muslims stand together checking their watches. There are approximately 1 billion Muslims in the world, a large percentage of them not Arab, and about 320 million Arabs in the Middle East, the overwhelming majority of them not terrorists. Our job is to think critically and rationally, and to ignore the cacophony of other interests trying to use terrorism to advance political careers or increase a television show’s viewership.

The surest defense against terrorism is to refuse to be terrorized. Our job is to recognize that terrorism is just one of the risks we face, and not a particularly common one at that. And our job is to fight those politicians who use fear as an excuse to take away our liberties and promote security theater that wastes money and doesn’t make us any safer.

This essay originally appeared on Wired.com.

EDITED TO ADD (3/24): Here’s another incident.

EDITED TO ADD (3/29): There have been many more incidents since I wrote this—all false alarms. I’ve stopped keeping a list.

Posted on August 24, 2006 at 7:08 AM • View Comments

Britain Adopts Threat Levels

Taking a cue from a useless American idea, the UK has announced a system of threat levels:

“Threat levels are designed to give a broad indication of the likelihood of a terrorist attack,” the intelligence.gov.uk website said in a posting. “They are based on the assessment of a range of factors including current intelligence, recent events and what is known about terrorist intentions and capabilities. This information may well be incomplete and decisions about the appropriate security response are made with this in mind.”

Unlike the previous secret grading system offering seven levels of threat, the new system has been simplified to five, starting with “low,” meaning an attack is unlikely, to “critical,” meaning an attack is expected imminently. Unlike American threat assessments, the British system is not color-coded.

The current level is “severe”:

“Severe” is the second-highest threat level, but the Web site did not say what kind of attack was likely. The assessment is roughly the same as it has been for a year.

I wrote about the stupidity of this sort of system back in 2004:

In theory, the warnings are supposed to cultivate an atmosphere of preparedness. If Americans are vigilant against the terrorist threat, then maybe the terrorists will be caught and their plots foiled. And repeated warnings brace Americans for the aftermath of another attack.

The problem is that the warnings don’t do any of this. Because they are so vague and so frequent, and because they don’t recommend any useful actions that people can take, terror threat warnings don’t prevent terrorist attacks. They might force a terrorist to delay his plan temporarily, or change his target. But in general, professional security experts like me are not particularly impressed by systems that merely force the bad guys to make minor modifications in their tactics.

And the alerts don’t result in a more vigilant America. It’s one thing to issue a hurricane warning, and advise people to board up their windows and remain in the basement. Hurricanes are short-term events, and it’s obvious when the danger is imminent and when it’s over. People can do useful things in response to a hurricane warning; then there is a discrete period when their lives are markedly different, and they feel there was utility in the higher alert mode, even if nothing came of it.

It’s quite another thing to tell people to be on alert, but not to alter their plans?as Americans were instructed last Christmas. A terrorist alert that instills a vague feeling of dread or panic, without giving people anything to do in response, is ineffective. Indeed, it inspires terror itself. Compare people’s reactions to hurricane threats with their reactions to earthquake threats. According to scientists, California is expecting a huge earthquake sometime in the next two hundred years. Even though the magnitude of the disaster will be enormous, people just can’t stay alert for two centuries. The news seems to have generated the same levels of short-term fear and long-term apathy in Californians that the terrorist warnings do. It’s human nature; people simply can’t be vigilant indefinitely.

[…]

This all implies that if the government is going to issue a threat warning at all, it should provide as many details as possible. But this is a catch-22: Unfortunately, there’s an absolute limit to how much information the government can reveal. The classified nature of the intelligence that goes into these threat alerts precludes the government from giving the public all the information it would need to be meaningfully prepared.

[…]

A terror alert that instills a vague feeling of dread or panic echoes the very tactics of the terrorists. There are essentially two ways to terrorize people. The first is to do something spectacularly horrible, like flying airplanes into skyscrapers and killing thousands of people. The second is to keep people living in fear with the threat of doing something horrible. Decades ago, that was one of the IRA’s major aims. Inadvertently, the DHS is achieving the same thing.

There’s another downside to incessant threat warnings, one that happens when everyone realizes that they have been abused for political purposes. Call it the “Boy Who Cried Wolf” problem. After too many false alarms, the public will become inured to them. Already this has happened. Many Americans ignore terrorist threat warnings; many even ridicule them. The Bush administration lost considerable respect when it was revealed that August’s New York/Washington warning was based on three-year-old information. And the more recent warning that terrorists might target cheap prescription drugs from Canada was assumed universally to be politics-as-usual.

Repeated warnings do more harm than good, by needlessly creating fear and confusion among those who still trust the government, and anesthetizing everyone else to any future alerts that might be important. And every false alarm makes the next terror alert less effective.

The Bush administration used this system largely as a political tool. Perhaps Tony Blair has the same idea.

Crossposted to the ACLU blog.

Posted on August 2, 2006 at 4:01 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.