CDR: Re: Public Key Infrastructure: An Artifact...

[Dennis Glatting]

obfuscation at beta.freedom.net wrote:
> 
> > On Sat, 18 Nov 2000 obfuscation at beta.freedom.net wrote:
> >
> > > Bram Cohen <bram at gawth.com> writes:
> > > > Unless that problem is fixed, man in the middle is hardly made more
> > > > difficult - for example, Mallory could break into some random machine on
> > > > the net and steal it's public key, then hijack local DNS and when someone
> > > > goes to amazon.com redirect them to amazon.hackeddomain.com, and then
> > > > proxy to amazon.com - now even SSL says the connection is safe.
> > >
> > > Are you sure that works?  I would think the SSL client would do a
> > > connection to the URL the user typed, www.amazon.com, and check the
> > > name in the cert to see if it (approximately) matches.
> >
> > When the user goes to www.amazon.com, they get a plaintext http redirect
> > to amazon.hackeddomain.com, which does check.
> 
> Still confused...
> 
> The original connection to www.amazon.com is an SSL connection, right?
> We are following an https: URL?  (Otherwise, SSL would not even come
> into the picture.)
> 
> If you do a DNS hack to redirect www.amazon.com to amazon.hackeddomain.com,
> the latter site will not be able to complete SSL handshaking without
> triggering a browser warning, will it?
> 

	[snip]

> 
> So it looks to me like the SSL protocol will not allow the redirection
> attack to work without triggering a user alert, unless there is some
> subtlety here...
> 

Definitely depends on the implementation, and perhaps browser
settings.