Re: [OAUTH-WG] Google's use of Implicit Grant Flow

[Jim Manico <[e-mail]>]

> Given a solid client library for JS, I think implicit flow is OK to use.

If you can, can you dig deeper here? What is it about this particular
library that makes its use of the OAuth 2 implicit flow secure? Signed
messages? Only supports registered clients? Something else?

Aloha, Jim


On 2/17/17 8:02 AM, Dominick Baier wrote:
> Given a solid client library for JS, I think implicit flow is OK to use. 
>
> But I agree that there are many “home grown” implementation out there
> that are not secure - and the necessary JS code to write a good client
> is not necessarily the “pit of success”.
>
> You should give this lib a go (it’s also a certified RP):
>
> https://github.com/IdentityModel/oidc-client-js
>
> Many people argue that handling the protocol and crypto pieces in JS
> is problematic (and I agree if no proper lib is used for that) - but
> at then end of the day the access token will end up in the browser -
> and a sloppy developer (e.g. not using CSP) will always write bad code
> that might lead to leaking a token.
>
> -------
> Dominick Baier
>
> On 17 February 2017 at 18:43:25, Adam Lewis
> ([e-mail]
> <mailto:[e-mail]>) wrote:
>
>> +1000
>>
>> We are currently going through internal turmoil over the usage of
>> implicit grant for ua-based apps.  The webapp case is well understood
>> and the WG has work in progress to define best practices for native
>> apps.  Having one for ua-based apps would be HUGELY beneficial
>>
>>
>>
>> On Fri, Feb 17, 2017 at 11:40 AM, Jim Manico <[e-mail]
>> <mailto:[e-mail]>> wrote:
>>
>>     Thank you to those answering my question on implicit for JS clients.
>>
>>     The responses so far seem to represent what the security world is
>>     saying  about the implicit grant - keep away from it other than
>>     for a few OIDC use cases.
>>
>>     Does anyone think it would be valuable to author a brief RFC to
>>     give clear OAuth 2 recommendations for JavaScript client developers?
>>
>>     I mean - the OAuth 2 body of work just needs a few more RFC's,
>>     right? :)
>>
>>     Aloha, Jim
>>
>>
>>
>>     On 2/17/17 6:03 AM, [e-mail]
>>     <mailto:[e-mail]> wrote:
>>>
>>>     Same for Deutsche Telekom. Our javascript clients also use code
>>>     flow with CORS processing and of course redirect_uri validation.
>>>
>>>      
>>>
>>>     Best regards
>>>
>>>      
>>>
>>>     Sebastian
>>>
>>>      
>>>
>>>     *Von:* OAuth [mailto:[e-mail]] *Im Auftrag von*
>>>     Bill Burke
>>>     *Gesendet:* Freitag, 17. Februar 2017 00:14
>>>     *An:* [e-mail] <mailto:[e-mail]>
>>>     *Betreff:* Re: [OAUTH-WG] Google's use of Implicit Grant Flow
>>>
>>>      
>>>
>>>     For our IDP [1], our javascript library uses the auth code flow,
>>>     but requires a public client, redirect_uri validation, and also
>>>     does CORS checks and processing.  We did not like Implicit Flow
>>>     because
>>>
>>>     1) access tokens would be in the browser history
>>>
>>>     2) short lived access tokens (seconds or minutes) would require
>>>     a browser redirect
>>>
>>>     I'd be really curious to hear other's thoughts though.
>>>
>>>     [1] http://keycloak.org
>>>     <https://urldefense.proofpoint.com/v2/url?u=http-3A__keycloak.org&d=DwMD-g&c=q3cDpHe1hF8lXU5EFjNM_A&r=hS3A5qzQnW1hxYBhPrxNW10ESeDiiiRwR8H84JHIXTI&m=IfM1P0zp986kOQNk7-NwlgfRZMq5MppK0kISXhIOF_s&s=YExyuyZO5YNpSvS3mEUG5pjKAjRXXVT8Xvk8hIb-Efw&e=>
>>>
>>>      
>>>
>>>      
>>>
>>>      
>>>
>>>     On 2/16/17 5:44 PM, Jim Manico wrote:
>>>
>>>         Hello Folks,
>>>
>>>         I noticed that Google supports the OAuth 2 Implicit flow for
>>>         third-party JavaScript applications.
>>>
>>>         https://developers.google.com/identity/protocols/OAuth2UserAgent
>>>         <https://urldefense.proofpoint.com/v2/url?u=https-3A__developers.google.com_identity_protocols_OAuth2UserAgent&d=DwMD-g&c=q3cDpHe1hF8lXU5EFjNM_A&r=hS3A5qzQnW1hxYBhPrxNW10ESeDiiiRwR8H84JHIXTI&m=IfM1P0zp986kOQNk7-NwlgfRZMq5MppK0kISXhIOF_s&s=_Mig-zmCt1y9dZpCece1dqby3VmcZVOu2JPcmAwzwKU&e=>
>>>
>>>         Isn't this generally discouraged from a security POV? *Is
>>>         there a better OAuth 2 flow for third party SPA applications?*
>>>
>>>         Aloha,
>>>
>>>         -- 
>>>
>>>         Jim Manico
>>>
>>>         Manicode Security
>>>
>>>         https://www.manicode.com
>>>         <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.manicode.com&d=DwMD-g&c=q3cDpHe1hF8lXU5EFjNM_A&r=hS3A5qzQnW1hxYBhPrxNW10ESeDiiiRwR8H84JHIXTI&m=IfM1P0zp986kOQNk7-NwlgfRZMq5MppK0kISXhIOF_s&s=H8pXLA4TE27vW-gz5Sbr9VOUP-KZMmd-gQ-okH4ohMU&e=>
>>>
>>>
>>>
>>>
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>>>
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>>>         <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ietf.org_mailman_listinfo_oauth&d=DwMD-g&c=q3cDpHe1hF8lXU5EFjNM_A&r=hS3A5qzQnW1hxYBhPrxNW10ESeDiiiRwR8H84JHIXTI&m=IfM1P0zp986kOQNk7-NwlgfRZMq5MppK0kISXhIOF_s&s=jAjifWdP3vqnDgWricLE62R9_d0BQReWRUitqM5S1JU&e=>
>>>
>>>      
>>>
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>>     --  
>>     Jim Manico
>>     Manicode Security
>>     https://www.manicode.com
>>     <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.manicode.com&d=DwMD-g&c=q3cDpHe1hF8lXU5EFjNM_A&r=hS3A5qzQnW1hxYBhPrxNW10ESeDiiiRwR8H84JHIXTI&m=IfM1P0zp986kOQNk7-NwlgfRZMq5MppK0kISXhIOF_s&s=H8pXLA4TE27vW-gz5Sbr9VOUP-KZMmd-gQ-okH4ohMU&e=>
>>
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-- 
Jim Manico
Manicode Security
https://www.manicode.com