[dnsext] [Errata Held for Document Update] RFC4035 (8037)

RFC Errata System <rfc-editor@rfc-editor.org> Wed, 07 August 2024 15:37 UTC

To: elias.heftrig@sit.fraunhofer.de, roy.arends@telin.nl, sra@isc.org, mlarson@verisign.com, massey@cs.colostate.edu, scott.rose@nist.gov
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Subject: [dnsext] [Errata Held for Document Update] RFC4035 (8037)
Archived-At: <https://mailarchive.ietf.org/arch/msg/dnsext/cN15YX06pkYoWtHDlwdtkMBhfcw>
Date: Wed, 07 Aug 2024 15:37:25 -0000

The following errata report has been held for document update 
for RFC4035, "Protocol Modifications for the DNS Security Extensions". 

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid8037

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Status: Held for Document Update
Type: Technical

Reported by: Elias Heftrig <elias.heftrig@sit.fraunhofer.de>
Date Reported: 2024-07-18
Held by: Eric Vyncke (IESG)

Section: 5.3.1.

Original Text
-------------
   [...] the validator cannot predetermine which DNSKEY
   RR to use to authenticate the signature, and it MUST try each
   matching DNSKEY RR until either the signature is validated or the
   validator has run out of matching public keys to try.

Corrected Text
--------------
   [...] the validator cannot predetermine which DNSKEY
   RR to use to authenticate the signature, and it SHOULD try each
   matching DNSKEY RR until either the signature is validated or the
   validator has run out of matching public keys to try.

Notes
-----
The original text requires validators to invest an unreasonable amount of work to validate a given signature in case there are many such DNSKEY RRs. The issue was exploited in the construction of CPU resource exhaustion attacks (CVE-2023-50387). For more details see our publication with ACM CCS'24 on the KeyTrap denial of service vulnerabilities.

-- verifier note --
While the concern is valid, this erratum does not represent the DNSEXT WG consensus at the time of writing, i.e., it cannot be "verified"

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RFC4035 (draft-ietf-dnsext-dnssec-protocol-09)
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Title               : Protocol Modifications for the DNS Security Extensions
Publication Date    : March 2005
Author(s)           : R. Arends, R. Austein, M. Larson, D. Massey, S. Rose
Category            : PROPOSED STANDARD
Source              : DNS Extensions
Stream              : IETF
Verifying Party     : IESG

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