Am 24.02.2012 18:33, schrieb Paul Hartman: > On Fri, Feb 24, 2012 at 10:43 AM, Michael Orlitzky <mich...@orlitzky.com> > wrote: >> On 02/24/12 02:45, Florian Philipp wrote: >>> >>> Let's not forget that whenever you are presented with that warning, it >>> could also be a man-in-the-middle attack. Therefore just clicking on >>> "Accept" on every site is about the stupidest thing you can do. >>> >>> I'm unsure how the warning looks when you have previously accepted a >>> normally untrusted certificate on that site and now it is different >>> (which could be an indication of MITM). I hope there is a big red flashy >>> warning but I doubt it. >>> >> >> Not if the certificate is "valid." >> >> The only sane way to handle certificates with parties you've never met >> (i.e. every website) is the SSH method: you accept that, no matter what, >> there's always going to be one opportunity for a man-in-the-middle >> attack. The first time you connect, you save the remote server's >> certificate. If it changes, freak out. >> >> The certificate patrol extension does this: >> >> http://patrol.psyced.org/ >> >> With it, self-signed certificates become more secure than CA-signed ones. > > Thanks for the link. The MultiZilla extension way back in the > Netscape/Mozilla/Seamonkey 1.x days treated certificates like this: > you had to approve all certs the first time, even if they were from a > trusted CA and if it ever changed for any reason, it would refuse to > connect unless you approved the new cert. > > It seems to me that's how it should *always* work, in all software > that uses SSL certificates, but I understand wanting to keep it simple > for non-technical users... but those are the very users most at risk, > probably the most likely to use hostile wifi networks (in my mind, > hostile is anything other than the router I control at my house). > > Additionally http://perspectives-project.org/ or > http://convergence.io/ can help you in establishing the initial trust > and are an attempt at eliminating the need to trust CAs at all. >
Just a small follow-up: A neat server-sided trick I didn't know until now is HTTP Strict Transport Security [1]. It prevents users from clicking away SSL warnings and prevents mixed content. [1] http://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security Regards, Florian Philipp
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