Re: [OAUTH-WG] Client authentication on token revocation

2020-08-20 Thread Emond Papegaaij
Hi Torsten, Thanks for your insight. I agree, a sender constraint token, such as when using certificate bound tokens from RFC 8705, cannot be used by an attacker. It makes sense to only allow the owner to revoke them, probably using the same mechanism as by which they are bound to the client. For

Re: [OAUTH-WG] Client authentication on token revocation

2020-08-20 Thread Torsten Lodderstedt
Hi Emond, I tend to agree with your assessment. Revoking bearer tokens without client authentication seems to be better than leaving the attacker the option to use them to invoke resources. However, if the attacker cannot use the access tokens (e.g. because they are sender constrained), the

[OAUTH-WG] Client authentication on token revocation

2020-08-20 Thread Emond Papegaaij
Hi all, We are currently implementing the token revocation endpoint (RFC 7009) on our authorization server and do not understand why it requires client authentication. When a party (a valid client or not) gets hold of a valid access token in whatever way, the least damaging it could do with it,