A guy by the name of Perry Metzger wrote up an interesting analysis of the big terrorist plot that was thwarted in London recently in which he ponders how plausible the scenario might be:
First, a note of introduction. Until recently, I was a computer security guy, and as with many in my profession, the application of computer security analysis to non-computer security problems was increasingly interesting to me. Now, for reasons that don’t need exploring at this juncture, I’m back at school, studying chemistry, and I’m spending this summer in a lab doing organic synthesis work. Strangely, today I find my interests colliding.
So, I’m doing a bunch of reading, and I find the claimed method the “highly sophisticated” attackers came up with for bringing down airliners kind of implausible. I wonder if it could ever work in reality.
A disclaimer, I’m working entirely off of news reported by people who don’t know the difference between soft drinks and nail polish remover, but the information I’ve seen has the taste of being real. As near as I can tell, it is claimed that the terrorists planned to make organic peroxides in situ on board an airplane and use them to destroy the plane.
This seems, at least given my initial examination of the idea, implausible.
He then goes on to explain why and it certainly gives one reason to ponder if this isn’t all much ado about nothing. Which isn’t to say that there may not be binary liquid explosives out there that could be used to bring down a plane—I’m certainly no chemist myself—but it does appear that the chemicals the news reports are suggesting were being considered are at best impractical. Given the overly volatile nature of the resultant mixture the claims that iPods and other portable electronic devices would’ve been used to set off the explosion are simply ridiculous as all it would take is a good smack to set that crap off.
There are other open questions I have here as well. Assuming this is really what was planned, why are the airport security making people throw away their shampoo? If you open a shampoo bottle and give it a sniff, I assure you that you’ll notice concentrated sulfuric acid very fast, not that you would want to have your nose near it for long. No high tech means needed for detection there. Acetone is also pretty distinctive—the average airport security person will recognize the smell of nail polish remover if told that is what they’re sniffing for. Oh, and even if they used a cousin of acetone, say methyl ethyl ketone (aka MEK, aka 2-butanone), you’ll still pick up on the smell.
Which just reinforces the simple idea that it takes people trained properly on what to look for to add a reasonable amount of protection as opposed to all sorts of new gadgetry to sniff out explosives.
From there the note takes an interesting turn with Perry proposing any of a number of alternative means for terrorists to cause mayhem that wouldn’t be terribly difficult to pull off—none of which we’re currently doing anything to combat:
And now, on to the fun part of this note. First they came for the nail clippers, but I did not complain for I do not cut my finger nails. Now they’ve come for the shampoo bottles, but I did not complain for I do not wash my hair. What’s next? What will finally stop people in their tracks and make them realize this is all theater and utterly ridiculous? Lets cut the morons off at the pass, and discuss all the other common things you can destroy your favorite aircraft with. Bruce Schneier makes fun of such exercises as “movie plots”, and with good reason. Hollywood, here I come!
We’re stopping people from bringing on board wet things. What about dry things? Is baby powder safe? Well, perhaps it is if you check carefully that it is, in fact, baby powder. What if, though, it is mostly a container of potassium cyanide and a molar equivalent of a dry carboxylic acid? Just add water in the first class bathroom, and LOTS of hydrogen cyanide gas will evolve. If you’re particularly
crazy, you could do things like impregnating material in your luggage with the needed components. Clearly, we can’t let anyone carry on containers of talc, and we have to keep them away from all aqueous liquids.
And also....
Then, lets consider books and magazines. Sure, they look innocent, but are they? For 150 years, chemists have known that if you take something with high cellulose content—cotton, or paper, or lots of other things—and you nitrate it (usually with a mixture of nitric and sulfuric acids), you get nitrocellulose, which looks vaguely like the original material you nitrated but which goes BOOM nicely. Nitrocellulose is the base of lots of explosives and propellants, including, I believe, modern “smokeless” gunpowder. It is dangerous stuff to work with, but you’re a terrorist, so why not. Make a bunch of nitrocellulose paper, print books on it, and take ‘em on board. The irony of taking out an airplane with a Tom Clancy novel should make the effort worthwhile.
So, naturally, we have to get rid of books and magazines on board. That’s probably for the best, as people who read are dangerous.
Indeed they are. Nothing more frightening than an educated mind, just ask the Pope.
Perry goes on to ask where it’ll all end. Will we get to the point where we’re not allowed to carry anything onto the plane and will have to fly naked after submitting to a full body cavity search? Even then, he suggests, that may not be enough:
If we’re looking for a movie plot, why not just get a sympathetic surgeon to implant explosives into your abdomen! A small device that looks just like a pace maker could be the detonator, and with modern methods, you could do something like setting it off by rapping “shave and a haircut” on your own chest. You could really do this—and I’d like to see them catch that one.
Go read the full essay. It’ll help put things into perspective.
Link found on Boing Boing.
Posted on 08/16/2006 at 12:26 PM 
Okay, it’s official. I’m never flying again.
Actually, I was with a group of people having a similar discussion the other night—we also brought up the surgery and body cavity issues (sick minds) and wondered about powders.
What amazes me most is that no one has done/tried any of these things—most of which would be undetectable by any current screeening method. It seemed to us that it was virutually impossible to prevent a terror attack if someone really wants to do it. So, why not? Why have there been no attacks of any size in the US in the last 5 years??
We can’t seriously believe that it is because (as Bush would claim) the new security methods are so very effective.
(Interesting post, Les!)