Re: [Cryptography] Toxic Combination
On Mon, Dec 1, 2014, at 08:55 AM, Guido Witmond wrote:
I'm starting to consider the combination of current best practice with server certificates and password to be a Toxic Combination.
The general issue is twofold:
People need to validate the authenticity of a site before typing in their password;
The password gets transmitted to the other party.
And this is taken advantage of every day by phishing attacks. However although your solution of setting up DNSSEC and DANE is the _correct_ solution, it's just too complex and hard to get right for a lot of system admins so it's not going to get uptake - just look at how PGP is also the _correct solution_ for encrypting messages and yet has not had the uptake since 1991! I think a better solution would be something like implementing Digest Authentication (RFC 2069, but replacing MD5 with something like AES-256 and allow it to be upgradable) in the browser. The password field value would then be replaced with the value from the DA call and no secrets would be leaked. This solution would get way faster adoption. Alfie
Most people assume that if it looks like their bank and the address bar is green then it should be safe. Regrettably, it’s not. Criminals obtain valid certificates using stolen creditcards and passports. The true method for authenticating a site requires verification of server certificate fingerprints. And if you don’t know what that means, you have to spot the spelling errors, the differences in layout and other mistakes to detect the scammers. Good luck!
The second part is just as problematic: The password must remain secret, yet it must be transmitted to the other side to log in.
This is the Toxic Combination. One failure to detect a scammer’s site and the password is compromised. The scammers can do everything that you can do with the password.
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For more information, please see:
http://eccentric-authentication.org/blog/2014/11/30/spot-the-differences.htm...
http://eccentric-authentication.org/Usable-Security.pdf
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-- Alfie John alfiej@fastmail.fm
On Sun, Nov 30, 2014 at 2:58 PM, Alfie John
I think a better solution would be something like implementing Digest Authentication (RFC 2069, but replacing MD5 with something like AES-256 and allow it to be upgradable) in the browser. The password field value would then be replaced with the value from the DA call and no secrets would be leaked. This solution would get way faster adoption.
There's also the FIDO Alliance's Universal Authentication Factor: http://fidoalliance.org/specs/fido-uaf-overview-v1.0-rd-20140209.pdf -- Tony Arcieri
On Mon, Dec 01, 2014 at 09:58:25AM +1100, Alfie John wrote:
just look at how PGP is also the _correct solution_ for encrypting messages and yet has not had the uptake since 1991!
the truth of this statement depends heavily on the threat model. the-amongst others-all-archiving kraaken is copying all pgp-cryptograms, as they are shiny beacons of cryptographic interest. not only do they generally disclose the recipients in plaintext metadata, but considering the ANT catalog, hacking team, finfisher FinISP and other market offers for cheap side channel attacks to recover key material, i would say this statement was true until a few years ago. -- otr fp: https://www.ctrlc.hu/~stef/otr.txt
participants (3)
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Alfie John -
stef -
Tony Arcieri