Quote:
Originally Posted by win32sux
(Post 3520296)
You are inspecting traffic which has been decrypted by the gateway, which is only feasible due to the fact that you had the clients encrypt it using the gateway's public key (instead of the server's). This is relatively easy to do in a corporative environment, since you can easily force the client hosts to accept the gateway's bogus certificate with or without the user's knowledge. Making this work outside the corporate environment is a whole different ballgame.
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The thing is, the Microdasys SKIP apparently doesn't require any certificate to be installed on the clients, according to people who have direct experience with it (I don't).
I can only imagine that means that it comes with a certificate built in that has been signed by one of the many 'trusted' CAs, with delegated CA authority.
Even outside the corporate environment all you need is a valid certificate from any
one of the many CAs trusted by default in browsers (IE has more than 100!) and control of the DNS the client is using (which any ISP has).
Quote:
Originally Posted by win32sux
(Post 3520296)
Ummm, no. We normally just check whether the certificate has been signed by a trusted third party. It would be insane if we needed to posses every HTTPS server's public key prior to the initial handshake.
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And that's the weak point! Do you trust all 50-100+ CAs that your browser trusts by default?
I don't, and therefore I have a separate browser installation only for online banking that only contains the certificate of the CA used by my online bank (I deleted all other default certificates), but this is only a clumsy stop-gap to a the fundamental insecurity of the SSL trust scheme.
All you need is one foul apple in between and the whole chain of trust is broken.
Just because your online bank uses for example Verisign (as many banks do), that doesn't mean that your browser wouldn't accept a valid certificate for it from any other CA too!
See here too for a real example:
http://www.theregister.co.uk/2008/12...lla_cert_snaf/
Of course we cannot realistically have public keys for every https server we interact with, but online banks should start providing them offline for maximum security.
Also my suggestion is that the browser stores certificates the first time it gets them and then later warns you if they change (unless they change because they have reached their expiry date), similar to how SSH does it.
Of course if the key you get the first time is bogus this won't help, but it still adds a layer of security for most situations.
Quote:
Originally Posted by win32sux
(Post 3520296)
The important thing to point out is that on computers you don't have full control over (such as is the case in a lot of people's work environment), there's no telling what bogus certificates might have been accepted on your behalf (in order to deploy MITM-based analysis solutions). Refraining from using your work computer for personal matters is a good habit to get into, as is refraining from letting other people use your account.
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Agreed and many people don't even realize this.