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[ietf-dkim] Re: dkim-threat-02 3.2. Use of Specific Identities

2006-01-19 19:27:00

On Jan 19, 2006, at 5:21 PM, Jim Fenton wrote:

The section 3.2. Use of Specific Identities constrains itself to what the recipient sees in every case. Concerns related to fallibility of humans being able to remember and recognize these identifiers would be an attack on the identity or SSP, but _not_ DKIM. These issues are important from the perspective of usurping the use of an identity which is the topic of this section. When relying upon humans to preform a validation of the identifier, it would appropriate to discuss the frailness of this validation within this section. At least reference these other sections.

Much of this is covered on 4.2.1. I suggested monitoring domain registrations rather than defensive acquisition of similar domain names as I think the monitoring will be needed by high-value domains regardless.

By the time a look-alike domain is noticed, much of the damage may have already been done. Many of these attacks could be measured in hours. There are many registrars involved and thousands of possible names. How timely will the potentially conflicting domain-names be reported, and how quickly can this domain be removed? Don't overlook the record TTLs. To be effective in a timely manner, services need to be stopped by the network provider. The timeliness would then assume providers can be contacted immediately, and that they understand and believe the request to be legitimate.

Keep in mind, a recognition scheme used in conjunction with DKIM never suffers from this susceptibility. There would be no emergency calls to Korea at 3 AM local-time, or keeping tabs on or the registering of thousands of possible names. In the threat draft, it would be good to clarify what is being attacked. DKIM does not have this problem, SSP does.

-Doug






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