Schneier on Security

Clive Robinson • December 23, 2017 5:24 PM

@ VinnyG,

Ubiquitous vehicle surveillance – are we there yet?

No nore are we ever likely to be, because it’s unnecessary.

You need to think in graphs, specifically nodes and the connecting edges / pathways.

There is rarely any reason to monitor an edge, because you have to pass through a node to get access to it. Thus the nodes are in effect “instrumented choke points” that you have to navigate to get anywhere.

Which is why the major nodes get instrumented first. For various reasons only around 2%-5% of nodes need to be instrumented to cover 50-90% of journeys at, atleast two points…

This is important for a couple of reasons, firstly it makes “Toll Tags” etc not need to be any more than an outside RFID thus cheap to make and monitor unlike camera based plate readers. Secondly the system is essentialy passive in nature, (which means “spoofing” is way way easier).

Thus the protocol the RFID tags are likely to use will in all probability be designed not for security but reliability (making spoofing easier).

Thus the authorities will have an established hierarchy of mainly low cost passive tracking systems. As long as they do not suspect you are manipulating the simple automated system they will not drill down to investigate the other systems, as that would be a needles use of valuable resources.

So if you fake someboby elses tag, they will accept the node logs unless they have reason to fall back to checking the saved video from which they might human verify the number plate. Likewise if you also fake the plates they will accept that record unless they have some reason to doubt it. The risk with faking a number plate is “street cops” who might stop you and cross check the drivers details, which is the apex of the technology for most current street cops, because of resources…

Obviously if you are of a technical persuasion and have some knowledge of the systems in use you can do two things. Firstly spoof/set up a false but accepted “trail”, second using other technology they don’t currently use, lay down a different trail for yourself as an alibi etc which would throw a wrench in the “beyond reasonable doubt” burden of the prosecution in court.

And this is the point, all these automatic systems are not “credible witnesses” in court. Any Police Officer presenting such as “proof” is in effect commiting purjury because they have “no first hand knowledge” thus are presenting hearsay as such. Which they know –from their training–
unlike many members of the public is not allowed, which means it’s not an acceptable error but a deliberate attempt to manipulate the evidence, thus a case will get binned fairly rapidly unless there is a strong motivation to keep at it.

Thus you need also when setting your alibi trail ensure your face is seen and recorded else where by either their systems or otherwise independent witnesses, such as a waiter at a bar or restaurant where you pay with a CC etc…

It’s interesting to note that some of the brighter young street criminals in London give their phone travel card and recognisable Hoodie Jacket, even a bank card etc to those of similar size and stature so that an alibi is established…

The dumb ones supprisingly still use their phones to take selfies of themselves and their mates either “in the act” or with the “proceads of their crimes”, even though how the police find and use such videos/photos has been shown on TV Crime-Stop programs. As the idiots also tend to be the violent types, natural selection shows societal benifit from time to time…

Clive Robinson • December 23, 2017 7:48 PM

@ Bruce and the usuall suspects,

Mat Green on an old NSA backdoor via “Extended Random” and “Dual-EC”, that was not realy found to exist in the wild… untill it just showed up in some Canon Printers due to a protocol SNAFU,

https://blog.cryptographyengineering.com/2017/12/19/the-strange-story-of-extended-random/

Clive Robinson • December 23, 2017 8:22 PM

@ Nick P, Figureitout,

If you guys are still lurking, fitstly have a happy winter solstice festival. And if you get a chance have a read of this,

https://spectrum.ieee.org/semiconductors/devices/the-high-school-student-whos-building-his-own-integrated-circuits

It’s about a 17year old making his own chips in his garage. Though they might be 10u that’s still going some.

Clive Robinson • December 24, 2017 4:26 PM

@ Winston Smith and iterested others,

From the Wired article on Ed Snowdens Haven we get,

In WIRED’s initial tests of Haven’s beta version, the app successfully detected and alerted us to any attempts to approach a laptop on an office desk … If anything, the app was too sensitive to saboteurs; it picked up and alerted us to every stray office noise. The app’s accelerometer detection was so hair-triggered that even leaving the phone on top of a computer with a moving fan inside created hundreds of alerts.

The “over sensitivity” is actually quite a good sign, as it indicates it probably has a suitable dynamic range available.

The trick now is to not “adjust sensitivity” but “adjust sensitivity in frequency bands”.

For instance the fan in a computer has a recognizable and learnable frequency spectrum. If you create “an inverse transform” you in effect either remove or significantly reduce the fan noise in the signal you process further for signs of saboteurs.

But of more interest most mechanical noises are,fairly determanistic in their behaviour, thus any change indicates that something has changed in the environment. It might not be a person or other entity but the fact there has been a change should be noted and considered with respect to other sensor inputs

The chances are it is something like clouds clearing alowing stronger sunlight hit the computer case causing it’s temprature to increase thus causing the fan to work harder to remove the increased excess thermal energy. However it should also cross correlate with other sensor data such as that measuring light levels. It it does not correlate then it could indicate that there is an EM Fault Injection attack etc in progress, which is being tried from a remote location.

At the end of the day there are trade offs to be made as resources are finite. That is there is only a certain number of CPU cycles you will get with any given battery state, thus a choice has to be made between what gets monitored, recognised and communicated versus battery life.

Unfortunately this opens loop holes that adept specialists can exploit, “IFF” they are sufficiently predictable. Thus the more “knobs to twiddle” by a user the less chance a specialist has to slip through any loop holes.

Nobody ever said security was easy 😉

Clive Robinson • December 24, 2017 9:15 PM

@ Jack,

Your computer has security knobs?

From the article we were talking about an input being too “sensitive”… Traditionaly to adjust sensitivity you would “twiddle the knob” to get the desired level of response. Some one who does this almost involuntarily is often called “A knob twiddler”, for instance various rock musicians who have been known to continuously adjust their instrument especially bases or their effects devices like the “sustain” have been called “A bit of a knob twiddler” at practice sesions. In the satirical film “This is Spinal Tap” there is a famous scene where one of the band members is seen discousing the bands knobs with a journalist and how their kbobs are special because “they go all the way to eleven”[1].

Even our host @Bruce in his book about Hawks and Doves showed a first order system with control knobs.

Such knobs are quite frequent in certain types of physical instruments to show exitation levels and response. Thus to make the computer simulations more “realistic” they show analogs of knobs on the screen that you can twiddle to your hearts content all day long even though they are not physical in nature.

But incase you are not sure of what a knob is in English english. From thae Cambridge dictionary,

https://dictionary.cambridge.org/dictionary/english/knob

knob noun [C] (ROUND OBJECT)

C1,

a round handle, or a small, round device for controlling a machine or electrical equipment:
a brass door knob
Turn/Twiddle the little knob to adjust the volume.
a round lump on the surface or end of something

[1] https://m.youtube.com/watch%3Fv%3DN3L4EZwmRrA

Clive Robinson • December 25, 2017 8:07 AM

@ Rachel,

Some countries have another definition for the word knob.

Yes which is why Terry Pratchett invented a baudy song for Diskworld “A Wizards Staff has a knob on the top” to be sung by a obe toothed Witch with gusto 😉

For fun, imagine a male baritone voice, with a stiff upper lip and “Plummy Mid Surrey” English accent of the “Mad Dogs and Englishmen” type as beloved by American TV Producers, reading out my reply to Jack and you should see it in a different way 😉

@ tyr,

Class system enforced by food differences has been used for social control for millenia.

It was not just food but many aspects of life including what cloths could be worn, with unolesant death as punishment.

In reality what lies behind it is “status”. Some people would willingly give up half their wealth and power in life, if it dimminished the status of the masses, such that the “status gap” was increased to their benifit.

It’s sad but true, such people exist and will fight tooth and claw to be seen as better than others and rub it in their faces. It’s kind of worse than being a Z list celebrity with narcissistic sociopath disorders, and “daddy” to have left enough money such that they can buy their own authoritarian followers.

Clive Robinson • December 27, 2017 6:02 AM

@ 65535,

How is AV successfully stripping SSL and sending files back home.

There are two ways to get access to enciphered plaintext,

1, Get access to the PlainText.
2, Get access to the KeyMat.

The first is done by getting between the application decryption and the HCI / UI. This generally requires an end run attack via the users computer at the device driver or memory level, which if the OS is any good would require high privilege levels. One way is to in effect install an executable or patch to the application on the HD such that the OS accepts it and executes it and it then “pipes” the plaintext to another executable.

The second can be done similarky by getting the KeyMat from the application memory space. But a second way is to take advantage of incompetantly specified Standards / Protocols / Applications. In essence you get faux KeyMat accepted by the users application and run a MITM attack.

As Wael has pointed out some combined CA’s and AV suppliers have been caught doing this, and they then run the “Rouge Employee” defence in public. Which most here would say “cough cough BS cough cough”. The chances are that such employees are doing what their “Pay Masters Instruct” which just leaves the question of who the pay masters are they hold most allegiance to…

But the real people who should be taken out and out on top of the pyre is those that design and implement the insecure Standards / Protocols / Applications. As I’ve noted in the past the W3C is a major offender when it comes to selling users privacy down the river, but they are just one of many…