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New NSA Leak Shows MITM Attacks Against Major Internet Services

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Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#71

Post by einaros »

moxie wrote: post #65

Trevor Perrin and I have been working on a dynamic certificate pinning proposal called TACK to help mitigate these types of attacks: http://tack.io In the current state of the world, we're all dependent on CA signatures for each connection we make to a website. TACK is a layer of indirection away from CA certificates, such that we'd only be dependent on CA signatures the very first time we contacted a website. It doe…

While an absolute necessity, it doesn't solve the immediate issue of NSLs and widespread use of unnecessary services.

Let's say that the NSA would like to track bitcoin transactions through MtGox. I don't know how easy it would be for them to plug a backdoor into a server in Japan, and let's assume that the NSA can't break the RC4 crypto their web server is configured to use ..

Since MtGox uses Google Analytics, and possibly pull other scripts from Google's CDN, they could either eavesdrop on whatever data comes back from them by default -- or insist that changes are made to ... pick up more.

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#72

Post by moxie »

MichaelSalib wrote: post #68
moxie wrote: post #65

Trevor Perrin and I have been working on a dynamic certificate pinning proposal called TACK to help mitigate these types of attacks: http://tack.io In the current state of the world, we're all dependent on CA signatures for each connection we make to a website. TACK is a layer of indirection away from CA certificates, such that we'd only be dependent on CA signatures the very first time we contacted a website. It doe…

Your tack.io proposal looks great. Do you have any sense as to whether or when it will be adopted?

We have some large websites on board to deploy it, and Trevor has been working with browser vendors to get it integrated. The latter has been pretty slow going, but there is interest.

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#73

Post by moxie »

einaros wrote: post #71
moxie wrote: post #65

Trevor Perrin and I have been working on a dynamic certificate pinning proposal called TACK to help mitigate these types of attacks: http://tack.io In the current state of the world, we're all dependent on CA signatures for each connection we make to a website. TACK is a layer of indirection away from CA certificates, such that we'd only be dependent on CA signatures the very first time we contacted a website. It doe…

While an absolute necessity, it doesn't solve the immediate issue of NSLs and widespread use of unnecessary services. Let's say that the NSA would like to track bitcoin transactions through MtGox. I don't know how easy it would be for them to plug a backdoor into a server in Japan, and let's assume that the NSA can't break the RC4 crypto their web server is configured to use .. Since MtGox uses Google Analytics, and…

Yes, absolutely, there are more hurdles. As an extension of this pinning work, Trevor has also been working on a proposal for 3rd party includes that would allow you to specify a hashsum in the include line, as well as a proposal that would fix cookie scoping in backwards compatible way.

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#74

Post by ck2 »

moxie wrote: post #65

Trevor Perrin and I have been working on a dynamic certificate pinning proposal called TACK to help mitigate these types of attacks: http://tack.io In the current state of the world, we're all dependent on CA signatures for each connection we make to a website. TACK is a layer of indirection away from CA certificates, such that we'd only be dependent on CA signatures the very first time we contacted a website. It doe…

Does OCSP stapling help or hurt? How similar to TACK?

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#75

Post by einaros »

moxie wrote: post #73
einaros wrote: post #71

Earlier quoted context omitted.

While an absolute necessity, it doesn't solve the immediate issue of NSLs and widespread use of unnecessary services. Let's say that the NSA would like to track bitcoin transactions through MtGox. I don't know how easy it would be for them to plug a backdoor into a server in Japan, and let's assume that the NSA can't break the RC4 crypto their web server is configured to use .. Since MtGox uses Google Analytics, and…

Yes, absolutely, there are more hurdles. As an extension of this pinning work, Trevor has also been working on a proposal for 3rd party includes that would allow you to specify a hashsum in the include line, as well as a proposal that would fix cookie scoping in backwards compatible way.

That would pretty much cover the use of CDNs that have proper versioning schemes.

Analytics, however, will remain something I'm not overly fond of. For many sites it's unnecessary. For others it's something they could nearly just as easily license and deploy to their own servers. Pulling scripts in from Google Analytics, Statcounter and others -- and especially into privacy concerned apps -- is downright irresponsible.

As I noted here: https://2x.io/read/would-the-nsa-infiltrate-cdns-to-circumve..., even Norway's tax returns site (which hosts info I'd rather not have in any foreign company's hands) use external analytic scripts. They and 90% of the rest of the internet.

No wonder the NSA claim they can circumvent most HTTPS encryption.

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#76

Post by devx »

moxie wrote: post #72
MichaelSalib wrote: post #68

Earlier quoted context omitted.

Your tack.io proposal looks great. Do you have any sense as to whether or when it will be adopted?

We have some large websites on board to deploy it, and Trevor has been working with browser vendors to get it integrated. The latter has been pretty slow going, but there is interest.

Maybe browser vendors will take it more seriously now, and with more urgency.

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#77

Post by JshWright »

ck2 wrote: post #74
moxie wrote: post #65

Trevor Perrin and I have been working on a dynamic certificate pinning proposal called TACK to help mitigate these types of attacks: http://tack.io In the current state of the world, we're all dependent on CA signatures for each connection we make to a website. TACK is a layer of indirection away from CA certificates, such that we'd only be dependent on CA signatures the very first time we contacted a website. It doe…

Does OCSP stapling help or hurt? How similar to TACK?

It doesn't really impact the MiTM attacks described in the article.

An attacker who is able to sit in the middle with their own trusted cert is simply going to not bother passing the stapled OCSP response along. The victims browser will do an OCSP lookup (or not...) for the trusted cert the attacker provided, and that will succeed.

I'm not sure how OCSP caching is implemented in the browsers that implement OCSP in the first place (is there a spec for caching?), but as it's a method for checking the revocation status of certs, it can't be cached long.

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#78

Post by dkl »

dpeck wrote: post #62

A bit surprised at the shock here, CAs are, for the most part, in the lawful intercept business and have been as long as they've existed. Moxie Marlinspike and others have been talking about this for years. Its a recognized problem, and thats why apps that are serious about protecting communications have been moving to a pinning model. Obviously this sucks at the browser level, though Chrome protect does this with Go…

Please give some references about this "pinning model," as I'm having difficulty finding anything via google. Thanks.

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#79

Post by fejr »

dkl wrote: post #78
dpeck wrote: post #62

A bit surprised at the shock here, CAs are, for the most part, in the lawful intercept business and have been as long as they've existed. Moxie Marlinspike and others have been talking about this for years. Its a recognized problem, and thats why apps that are serious about protecting communications have been moving to a pinning model. Obviously this sucks at the browser level, though Chrome protect does this with Go…

Please give some references about this "pinning model," as I'm having difficulty finding anything via google. Thanks.

Parent is refering to public key pinning. Chrome for instance has been doing it the last couple years [1].

Also see Moxie's comment in this very thread. [2]

[1] https://www.imperialviolet.org/2011/05/04/pinning.html

[2] https://news.ycombinator.com/item?id=6381673

Re: New NSA Leak Shows MITM Attacks Against Major Internet Services

#80

Post by anologwintermut »

taway2012 wrote: post #52
anologwintermut wrote: post #31

I'd say this is likely bullshit at least that it was done against a Brazilian company. Why take the risk of getting caught and burning your ability to do this when you can get the information from Google? 1) Chrome(and some plugins) pin's certificates and would notice a man in the middle attack(unless it was done with google's key). Sure, most corporate targets probably use IE, but if anyone uses chrome on or one of…

AFAIK, Chrome "certificate pinning" may not exactly be what you think "certificate pinning" means. It should be more precisely called "certificate authority pinning". What it means is that Chrome will not trust certs for Google properties except those issued by certain certificate authorities. Reference: https://www.imperialviolet.org/2011/05/04/pinning.html Unless things changed since I last checked. In contrast, "r…

You are correct chrome pins the authority, not the cert. And at least as for 2011, they don't just pin their own sub authority, they include a couple of real authorities who's keys the NSA might have.

https://www.imperialviolet.org/2011/05/04/pinning.html

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