There are two ways to target MITM attacks. First is the attack against the user, sending everything destined for TLS (either via HTTP proxy or via port-fowarding techniques) from the user's machine to the attacker. Second is the attack against the server, sending network traffic destined for the server -- to the attacker (this seems to be the 'classical' view, that a bank is a bigger fish and thus a bigger target than the individual user).
Both of these types of attack can be done via Cisco IOS's enable, even without reconfiguring the user's system to talk through a proxy. I was concerned when the IOS buffer overflow was announced, as well as the IOS rootkit. Bernie's solution might actually be doable, if you could get all of the CAs who are in Firefox's trust list to check with each other on the subjects, subject alternative names and organizations who are registering certificates, and perhaps even make an XML-RPC or SOAP query interface to this checking mechanism available to the public. (Of course, they're all competitors, so they're unlikely to share information about their client bases.) This would allow for an emulation of the underlying condition that actually makes X.509 theoretically work -- the notion of the central X.500 Directory, where everything about a given Subject could be looked up from a delegated, distributed database very much like DNS. The basic idea for querying this would be as follows: hash the Subject and each/all SANs in the certificate, and query for that hash (perhaps to a web service). If there's a match, ensure it's signed by a CA in the default db; if it isn't, conclude that it's an MITM. If there isn't a match, pop up a small notification (like the 'Firefox has blocked this download' notification) that Firefox can't authenticate the certificate, and they proceed at their own risk. (If they add the certificate to their store, the notification can say "You've manually accepted the certificate for this site, Firefox didn't do it automatically"?) I would have no problem with changing the chrome when people step outside of the assurances that Firefox tries to provide. I /do/ have a problem with removing the ability for users to try to self-organize their own networks. (The threat model is different, the policies are different, and the fact that everyone on this list is talking about removing the ability for self-signed roots to be used at all is an extremely counterproductive and cartel-supporting view.) -Kyle H On Fri, Nov 7, 2008 at 1:09 AM, Eddy Nigg <[EMAIL PROTECTED]> wrote: > On 11/07/2008 05:18 AM, Kyle Hamilton: >> >> So, essentially, what you're saying is that it was a targeted attack >> against a user, instead of an attack targeted against a server? >> > > What is an attack targeted against a server in the context of browsers and > MITMs? > > > -- > Regards > > Signer: Eddy Nigg, StartCom Ltd. > Jabber: [EMAIL PROTECTED] > Blog: https://blog.startcom.org > _______________________________________________ > dev-tech-crypto mailing list > dev-tech-crypto@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-tech-crypto > _______________________________________________ dev-tech-crypto mailing list dev-tech-crypto@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-tech-crypto
