Matt Blaze: How unpredictable screening helps terrorists • Hacker News Board

Re: Matt Blaze: How unpredictable screening helps terrorists

#21

Post by rogersm » Thu, Dec 31, 2009, 7:29 PM UTC

alterego wrote: post #20

rogersm wrote: post #17

Earlier quoted context omitted.

First of all I must say I don't believe in these kind of unpredictable systems: rarely doing this 'select randomly the process from a set of processes' works better than using the best process in the set. But I don't think this applies: But terrorist organizations -- especially those employing suicide bombers -- have very different goals and incentives from those of smugglers, fare beaters and tax cheats. Groups like…

But if you read the article, I believe the point was that if the terrorist gets caught under a random system, the terrorist still achieves a positive result for the terrorists (the govt becomes forced to shut down aviation and then apply the maximum screening to everyone, causing expensive chaos and terror of its own).

This is not the kind of chaos of terror the terrorist has on his mind. Otherwise they will be shutting down traffic light control systems.

Getting caught is a failure. A bomb exploding is a victory.

Re: Matt Blaze: How unpredictable screening helps terrorists

#22

Post by almost » Thu, Dec 31, 2009, 7:40 PM UTC

tptacek wrote: post #6

CWuestefeld wrote: post #3

Relevant parts: Paradoxically, the best terrorist strategy (as long as they have enough volunteers) under unpredictable screening may be to prepare a cadre of suicide bombers for the least rigorous screening to which they might be subjected, and not, as the strategy assumes, for the most rigorous. Sent on their way, each will either succeed at destroying a plane or be caught, but either outcome serves the terrorists'…

The idea that Matt Blaze thinks the three-ounce rule is sensible was surprising to me; I hit it, jumped back to the top, and re-read the whole article. What's the flaw in his reasoning? The three-ounce rule always seemed like one of the more ridiculous TSA measures.

If you think about it there are things you can do with a not too large an amount of liquid chemicals that would cause serious problems on plane. I don't think making explosives is one of them.

Re: Matt Blaze: How unpredictable screening helps terrorists

#23

Post by gojomo » Thu, Dec 31, 2009, 8:06 PM UTC

rogersm wrote: post #17

tptacek wrote: post #5

This article demonstrates what I like about Matt Blaze's physical security writing that I don't like about Schneier's. Both are computer security experts by training, but Blaze's writing has a concrete engineering-driven perspective that Schneier's lacks. Schneier's writing always "feels" right, but leaves you with the sense that's it's not based on any operational reality. It's probably not a coincidence that Matt B…

First of all I must say I don't believe in these kind of unpredictable systems: rarely doing this 'select randomly the process from a set of processes' works better than using the best process in the set. But I don't think this applies: But terrorist organizations -- especially those employing suicide bombers -- have very different goals and incentives from those of smugglers, fare beaters and tax cheats. Groups like…

Also, consider that the greatest threat is not from people who hope to live and accept a strategic risk of death. Rather, the greatest threat is from people who believe that death is the ultimate success, for both their worldly and otherworldly aims.

While a one-in-a-twenty chance of success sounds good from a terror chief's perspective, no suicide bomber wants a 95% chance of winding up in captivity, famous only as a failure. Out of the twenty, they want to be the one!

So plans that allocate many participants to expected capture will have far fewer volunteers. And every report of a capture will decrease potential-volunteers' willingness to sign up, because they will adjust upward their expectation of embarrassing capture rather than martyrdom.

Re: Matt Blaze: How unpredictable screening helps terrorists

#24

Post by RedJones » Thu, Dec 31, 2009, 8:27 PM UTC

"A few days later the TSA, to it's credit..."

Fail.

Re: Matt Blaze: How unpredictable screening helps terrorists

#25

Post by NikkiA » Thu, Dec 31, 2009, 8:31 PM UTC

tptacek wrote: post #6

CWuestefeld wrote: post #3

Relevant parts: Paradoxically, the best terrorist strategy (as long as they have enough volunteers) under unpredictable screening may be to prepare a cadre of suicide bombers for the least rigorous screening to which they might be subjected, and not, as the strategy assumes, for the most rigorous. Sent on their way, each will either succeed at destroying a plane or be caught, but either outcome serves the terrorists'…

The idea that Matt Blaze thinks the three-ounce rule is sensible was surprising to me; I hit it, jumped back to the top, and re-read the whole article. What's the flaw in his reasoning? The three-ounce rule always seemed like one of the more ridiculous TSA measures.

His reasoning appears to be 'no-one has blown a plane up with liquid explosives, therefore it must be working', at least that was the impression I got from the article.

Re: Matt Blaze: How unpredictable screening helps terrorists

#26

Post by tptacek » Thu, Dec 31, 2009, 8:31 PM UTC

chaosmachine wrote: post #14

tptacek wrote: post #12

Earlier quoted context omitted.

WHY? Really, how much do you think a PETN bomb costs? Re-read the article: nothing that happens in response to these attacks fails to help the terrorists. They send 5 people and one blows up a plane: huge positive ROI . They send 5 people and nobody blows up a plane, but commercial air travel is disrupted to the tune of hundreds of millions of dollars: huge positive ROI .

You have a good point, if you measure it in terms of financial damage, the terrorists win either way. A side point: I suspect bombs are at bottom of the price chart in terms of financing an attack. More likely, the most expensive part is finding someone stupid enough to blow themselves up, and getting them to the right place at the right time. The cost of doing this undetected would probably increase non-linearly wit…

Which is why Khalid Sheikh Mohammed never gets on the suicide flights. Terrorist management is expensive. Terrorist suckers are cheap, and if the history of the Iraq and Palestinian experience is an indicator, will get cheaper as AQ gets more operational experience.

Re: Matt Blaze: How unpredictable screening helps terrorists

#27

Post by ghshephard » Thu, Dec 31, 2009, 8:32 PM UTC

tptacek wrote: post #5

This article demonstrates what I like about Matt Blaze's physical security writing that I don't like about Schneier's. Both are computer security experts by training, but Blaze's writing has a concrete engineering-driven perspective that Schneier's lacks. Schneier's writing always "feels" right, but leaves you with the sense that's it's not based on any operational reality. It's probably not a coincidence that Matt B…

Another thing to note - Matt Blaze typically approaches security scenarios with a different cost/benefit perspective than Schneier, for example Blaze writes:

"The TSA's much maligned "three ounce" liquid rule is, in fact, a nice example of good security engineering of this kind. "

Schneier, on the other hand, considers the inconvenience to travelers to be not worth the hassle. He always seems to fail to recognize the principles of defense-in-depth, and over-emphasizes the importance of stopping the terrorist before they launch an attack. I say this as someone who has ready pretty much every essay and book he has ever written, sometimes multiple times.

For example:

http://www.schneier.com/blog/archives/2006/08/terrorism_secu...

". Banning box cutters since 9/11, or taking off our shoes since Richard Reid, has not made us any safer. And a long-term prohibition against liquid carry-ons won't make us safer, either. It's not just that there are ways around the rules, it's that focusing on tactics is a losing proposition."

o Banning box-cutters (and other sharp devices) has made it much more difficult to bring on an _effective_ weapon on board a plane. Nobody is denying that you can still fashion a shiv, of some kind - but the amount of damage you can do with a roughly fashioned hand weapon, versus something designed to kill lots of people at close range, is enough to deter people from trying to do so. Note - one of the principal reasons for banning box cutters and their like is so that the _other_ passengers on the plane have a pretty straightforward mechanism for subduing a malevolent passenger.

o Banning Large amounts of liquids, in the face of Liquid Bombs being _actually designed_ just makes good sense. Likewise banning powdered substances (PETN) from being brought onto planes makes sense now that we know that there are active attempts to use this vector.

Focusing on tactics is actually a very effective proposition - It's actually pretty damn difficult to bring down a plane these days from inside - not impossible, I'm sure there are a lot of vectors still left, but they are getting pretty few and far between. Not to say you don't still try and stop attacks at their source, but, if one gets by - you hope that further lines of defense will stop them.

Re: Matt Blaze: How unpredictable screening helps terrorists

#28

Post by tptacek » Thu, Dec 31, 2009, 8:37 PM UTC

rogersm wrote: post #17

tptacek wrote: post #5

This article demonstrates what I like about Matt Blaze's physical security writing that I don't like about Schneier's. Both are computer security experts by training, but Blaze's writing has a concrete engineering-driven perspective that Schneier's lacks. Schneier's writing always "feels" right, but leaves you with the sense that's it's not based on any operational reality. It's probably not a coincidence that Matt B…

First of all I must say I don't believe in these kind of unpredictable systems: rarely doing this 'select randomly the process from a set of processes' works better than using the best process in the set. But I don't think this applies: But terrorist organizations -- especially those employing suicide bombers -- have very different goals and incentives from those of smugglers, fare beaters and tax cheats. Groups like…

Ramping up a new KSM has a high cost. Ramping up a mujahedeen to skirmish with NATO in Khost has a high cost. Ramping up the guys who know how to rig PETN bombs has high cost. Ramping up guys who can operate safe houses and route money through a paranoid cell system has a high cost.

Building the system has a high cost. Using the system to exploit the dumbfucks who get captured by the system in order to get them to put the explosive underpants on is cheap.

If the system was jeopardized by any terrorist attempt, you'd be right. But it isn't. It's like spam. It may have a 0.001% conversion rate, but as long as it pays off 10000000:1, it's sustainable and resilient.

Re: Matt Blaze: How unpredictable screening helps terrorists

#29

Post by ghshephard » Thu, Dec 31, 2009, 8:38 PM UTC

tptacek wrote: post #6

CWuestefeld wrote: post #3

Relevant parts: Paradoxically, the best terrorist strategy (as long as they have enough volunteers) under unpredictable screening may be to prepare a cadre of suicide bombers for the least rigorous screening to which they might be subjected, and not, as the strategy assumes, for the most rigorous. Sent on their way, each will either succeed at destroying a plane or be caught, but either outcome serves the terrorists'…

The idea that Matt Blaze thinks the three-ounce rule is sensible was surprising to me; I hit it, jumped back to the top, and re-read the whole article. What's the flaw in his reasoning? The three-ounce rule always seemed like one of the more ridiculous TSA measures.

What is the alternatives to preventing liquid bombs from bringing down an Airplane? What Matt Blaze is saying, is that instead of eliminating _all_ liquids (which would have also prevented aircraft from catastrophic explosions) - the TSA simply did the engineering to determine what the smallest amount of liquid was required to do significant damage, and then limited bottled liquids to something smaller than that. People can still bring on toothpaste, shampoo, and other useful liquids/medicines, but at the same time can't bring them on in large enough volumes to destroy an airplane.

Re: Matt Blaze: How unpredictable screening helps terrorists

#30

Post by ghshephard » Thu, Dec 31, 2009, 8:41 PM UTC

jz wrote: post #18

tptacek wrote: post #6

Earlier quoted context omitted.

The idea that Matt Blaze thinks the three-ounce rule is sensible was surprising to me; I hit it, jumped back to the top, and re-read the whole article. What's the flaw in his reasoning? The three-ounce rule always seemed like one of the more ridiculous TSA measures.

I was also surprised by this. The three-ounce rule applies to a single passenger. All it takes is a bit of team work to get around it. A 747 for example can carry between 400 and 500 passengers depending on class layout. A team of 3 terrorists would represent less than 1% of the passengers.

Kip Hawley, former head of the TSA has answered this question a number of times, including conversations with Schneier. Most of the liquids that can do the type of damage the TSA are concerned about are likely highly oxygen reactive, or otherwise have significant obstacles to being combined outside of a lab environment.

If that weren't the case, the TSA would have simply banned all liquids.