Re: Use case - John and Jane

Le 23/03/2013 00:15, Ryan Sleevi a écrit :
> Aymeric,
>
> I'm sorry, your responses do not make any sense.

Would be cool that you avoid this kind of "gratuit" statement.

>
> Your original attack stated "John leaves 5mn to see the postman" and 
> "jane inserts from his webconsole an iframe"
>
> I described to you why physical attacks are out of scope.
>
> You've now suggested twice you're not describing physical attacks, 
> even though you explicitly did. If you're going to keep moving the 
> goal posts and changing the attack, I'm afraid we cannot have a 
> productive discussion of the risk model.

I am not changing the attack, what do you mean by "physical attack" ? I 
am taking back a WebCrypto Use Case example ("But at some point in time, 
a malicious user -- Jane Doe -- with access to the JavaScript console of 
John Doe's browser does something of the sort:") with a different 
attack, and by "she intercepts" I mean : she really intercepts the 
connection even if it is SSL/TLS, or she uses a more simple means like 
silent protocol analyzer, or other, a way that she can get John's messages.

>
> If a site is not using SSL/TLS, but instead rolling its own crypto, 
> then I'm sorry, but that cannot be dealt with in any reasonable way, 
> because it entirely breaks the same-origin-policy that is essential to 
> modern web security. While I'm sure novel, clever, amusing, and any 
> number of platitudes, the one that is missing is "secure", and so we 
> should not pretend it's a security risk to do something knowingly 
> insecure.

Sorry, no (see node-Tor OP again inside the browser, no need of 
SSL/TLS). I don't see why you associate SSL/TLS to SOP (while you 
insisted in other emails that there is no SSL/TLS associated to an 
origin), but that's another discussion.

>
>
>
> On Fri, Mar 22, 2013 at 4:12 PM, Aymeric Vitte <vitteaymeric@gmail.com 
> <mailto:vitteaymeric@gmail.com>> wrote:
>
>     I thought that by "physical access" you meant that Jane can access
>     John's computer.
>
>     But probably you mean that she intercepts John's connection. She
>     does not need to do so, she could get John's messages from his
>     computer (wireshark or other if no SSL/TLS for the site).
>
>     Again, unlikely but possible, because if the site relies on its
>     own secure system, it might not use SSL/TLS.
>
>     Regards,
>     Le 22/03/2013 23:45, Ryan Sleevi a écrit :
>>     I'm not sure what you mean - Jane's "use of web console" is a
>>     physical access attack.
>>
>>
>>     On Fri, Mar 22, 2013 at 3:42 PM, Aymeric Vitte
>>     <vitteaymeric@gmail.com <mailto:vitteaymeric@gmail.com>> wrote:
>>
>>         That's a different version of Jane's attack (from web
>>         console, then physical access) against John described in
>>         WebCrypto Use Cases.
>>
>>         More difficult and more unlikely, but maybe not if we go
>>         outside of John/Jane's simple context.
>>
>>         Then maybe it should be referenced somewhere.
>>
>>         Regards,
>>
>>         Le 22/03/2013 19:48, Ryan Sleevi a écrit :
>>>         Physical access attacks MUST remain out of scope of this work.
>>>
>>>
>>>         On Fri, Mar 22, 2013 at 11:12 AM, Aymeric Vitte
>>>         <vitteaymeric@gmail.com <mailto:vitteaymeric@gmail.com>> wrote:
>>>
>>>             Tricky, difficult or completely unlikely but maybe
>>>             possible : Use Case, John and Jane, Jane does not leave
>>>             John but wants to spy him, sometimes she uses his
>>>             computer then knows how to access it, while John is
>>>             visiting the social site he leaves 5mn to see the
>>>             postman, she inserts from his web console an iframe in
>>>             the page (jane.com <http://jane.com>) and sends a
>>>             postMessage with John's keys to the iframe which
>>>             "stores" (ie references the underlying data) the keys in
>>>             jane.com <http://jane.com>'s indexedDB. She intercepts
>>>             John's connexion and decrypt messages with John's
>>>             computer when he is out reinjecting messages using
>>>             jane.com <http://jane.com>.
>>>
>>>             Usually this will not work because outside origin
>>>             iframes can not access indexedDB, but indexedDB spec
>>>             just says : User agents MAY restrict access...
>>>
>>>             Regards,
>>>
>>>             -- 
>>>             jCore
>>>             Email : avitte@jcore.fr <mailto:avitte@jcore.fr>
>>>             iAnonym : http://www.ianonym.com
>>>             node-Tor : https://www.github.com/Ayms/node-Tor
>>>             GitHub : https://www.github.com/Ayms
>>>             Web : www.jcore.fr <http://www.jcore.fr>
>>>             Webble : www.webble.it <http://www.webble.it>
>>>             Extract Widget Mobile : www.extractwidget.com
>>>             <http://www.extractwidget.com>
>>>             BlimpMe! : www.blimpme.com <http://www.blimpme.com>
>>>
>>>
>>>
>>
>>         -- 
>>         jCore
>>         Email :avitte@jcore.fr  <mailto:avitte@jcore.fr>
>>         iAnonym :http://www.ianonym.com
>>         node-Tor :https://www.github.com/Ayms/node-Tor
>>         GitHub :https://www.github.com/Ayms
>>         Web :www.jcore.fr  <http://www.jcore.fr>
>>         Webble :www.webble.it  <http://www.webble.it>
>>         Extract Widget Mobile :www.extractwidget.com  <http://www.extractwidget.com>
>>         BlimpMe! :www.blimpme.com  <http://www.blimpme.com>
>>
>>
>
>     -- 
>     jCore
>     Email :avitte@jcore.fr  <mailto:avitte@jcore.fr>
>     iAnonym :http://www.ianonym.com
>     node-Tor :https://www.github.com/Ayms/node-Tor
>     GitHub :https://www.github.com/Ayms
>     Web :www.jcore.fr  <http://www.jcore.fr>
>     Webble :www.webble.it  <http://www.webble.it>
>     Extract Widget Mobile :www.extractwidget.com  <http://www.extractwidget.com>
>     BlimpMe! :www.blimpme.com  <http://www.blimpme.com>
>
>

-- 
jCore
Email :  avitte@jcore.fr
iAnonym : http://www.ianonym.com
node-Tor : https://www.github.com/Ayms/node-Tor
GitHub : https://www.github.com/Ayms
Web :    www.jcore.fr
Webble : www.webble.it
Extract Widget Mobile : www.extractwidget.com
BlimpMe! : www.blimpme.com

Received on Friday, 22 March 2013 23:50:07 UTC