Hi, Summarizing my thoughts and opinion on this issue. Changing the title to highlight the issues better.
As currently specified in draft-ietf-ace-oauth-authz-35, the RS will happily send the AS address to any node that asks. This causes two problems. - If C acts on the unauthorized information, this is an attack vector for DoS attacks as an attacker on the C-RS path can make C contact a chosen node on the Internet. - That RS shares the AS address with anybody that asks can be a severe privacy problem. If RS is a medical device, the AS address can reveal sensitive information. If RS is a blood pressure sensor it could e.g. be “AS address = coaps://as.hopkinsmedicine.org/kimmel_cancer_center/” The requirement "the client MUST be able to determine whether an AS has the authority to issue access tokens for a certain RS. This can for example be done through pre-configured lists, or through an online lookup mechanism that in turn also must be secured." indicates that C is required to have another mechanism to determine the AS for a specific RS and that the unauthorized AS address is completely redundant. The draft does not discuss the privacy issues of unauthorized AS addresses at all and the draft is diminishing the DoS issues by only talking about compromised RS and attacking an AS. This indicates that none of these issues has been discussed enough. I currently have a strong opinion that Unauthorized AS address should be removed from the specification. Cheers, John _______________________________________________ Ace mailing list Ace@ietf.org https://www.ietf.org/mailman/listinfo/ace
