Reviewer: Dave Thaler Review result: Ready with Issues I reviewed the diffs between RFC 4941 and draft-ietf-6man-rfc4941bis-11 and have the following comments. Section 1.2: The change from RFC 4941 to add "on unencrypted packets" in the paragraph starting "Note that an attacker, who is on path, may be able to perform significant correlation" is incorrect. That's because the 2nd bullet (about packet size and timing) can still apply to encrypted packets. Instead the "unencrypted" clause only applies to the first bullet. Either the change should be reverted, or else it should be moved into the first bullet. Similarly the text added to the end of 1.2 has the same problem. Deployment of encryption will not prevent correlation based on timing, and it will only prevent correlation based on packet size if padding is used to make packets all the same size. Simply encrypting does not solve this. Section 2: Grammatically, the addition of "and" is unnecessary and arguably poor grammar. I would hope the RFC editor would revert it if you didn't. Instead, Oxford comma fans will want to insert a comma before "and makes comparisons". Section 5: The change from "MUST NOT" to "SHOULD NOT" is in point 7 of section 3.4 (Generating Temporary Addresses) is, I would argue, a significant change that needs to be mentioned in section 5. Also, significant text from RFC 4941 (sections 2.2 and 2.3) was removed in the update and replaced with one sentence referencing RFCs 7721, 7707, and 7217. That's fine but I wonder why it isn't mentioned in section 5 (Significant Changes from RFC 4941). Unlike what the section title implies, the text of section 5 only contains the subset of significant changes "that an implementer should be aware of". I'd suggest also mentioning significant changes that other readers may want to know, since implementers are not the only audience for this doc (deployers, security analysts, application developers, and even end users may benefit from reading this document). Section 4: With the change to use a separate IID per prefix, I believe the 2nd paragraph should be augmented to point out that simply upgrading an RFC 4941-compliant node to an implementation of this draft can exacerbate the problem mentioned in this paragraph. Also, "neighbour" should be "neighbor" twice in that paragraph, for consistency with the other IPv6 RFCs. Section 9: RFC 4941 reused the same IID for multiple prefixes, with the rationale explained in point 4 of section 3 of the RFCs. With the change to use a separate IID per prefix, additional security considerations are needed since there is now a way to conduct new attacks that were not present before. Namely, by sending a large enough number of prefixes one can force the host into multicast promiscuous mode and thereby consume more host resources (e.g., drain battery). For regular hosts "large enough" might mean enough to generate 8 or 16 IIDs total (link-local + stable + temporary total), but for some smaller devices such as IoT devices, a much smaller number of prefixes (potentially just one more) might be needed to result in such an effect. -- last-call mailing list last-call@xxxxxxxx https://www.ietf.org/mailman/listinfo/last-call
