Yubikey NEO OpenPGP advisory

Andreas Schwier andreas.schwier.ml at cardcontact.de
Wed Apr 22 18:06:13 CEST 2015

Thanks for sharing.

I guess this once again shows that writing security sensitive software
is not about just hacking some lines of code, it's about putting
together a good (or better semi-formal) functional requirements
specification and a test framework that validates the correct
implementation of the defined mechanisms. With a proper test set-up -
which is relatively easy to do for a smart card application - this
should not have happened.

And contrary to the Yubico position that this is a minor issue, I would
call the circumvention of the PIN mechanism a major issue. If you loose
the device, then you loose the key.


On 04/21/2015 07:48 PM, Jose Castillo wrote:
> I haven’t seen this posted to the list yet, and thought it would be important for people who use the Yubikey NEO's OpenPGP functionality with GnuPG. It regards a vulnerability in the Yubikey NEO implementation of the OpenPGP smart card application: 
> https://developers.yubico.com/ykneo-openpgp/SecurityAdvisory%202015-04-14.html
> Yubikeys running the vulnerable software will generate signatures and decrypt session keys unconditionally, i.e. without verifying the user’s PIN. I reported this vulnerability to Yubico on 4/11, and to their credit it was quickly fixed. Still, if you are using a Yubikey that you obtained prior to the fix being issued, you should be aware that this vulnerability could affect your security. 
> This issue also affected the upstream javacardopenpgp project [1], which has been updated with a fix as well. 
> [1]: http://sourceforge.net/projects/javacardopenpgp/


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