[Curdle] [Errata Rejected] RFC8270 (5502)

[RFC Errata System <[e-mail]>]

The following errata report has been rejected for RFC8270,
"Increase the Secure Shell Minimum Recommended Diffie-Hellman Modulus Size to 2048 Bits".

--------------------------------------
You may review the report below and at:
https://www.rfc-editor.org/errata/eid5502

--------------------------------------
Status: Rejected
Type: Technical

Reported by: Eugene Adell <[e-mail]>
Date Reported: 2018-09-21
Rejected by: Deb Cooley (IESG)

Section: 5

Original Text
-------------
   A malicious client could cause a Denial of Service by intentionally
   making multiple connections that are less than 2048 bits in size.
   Therefore, operating systems SHOULD NOT log DH groups that are less
   than 2048 bits in size, as it would create an additional attack
   surface.

Corrected Text
--------------
   A malicious client could cause a Denial of Service by intentionally
   making multiple connections that are less than 2048 bits in size.
   Therefore, operating systems without any rate-limited logging 
   SHOULD NOT log DH groups that are less than 2048 bits in size, as it
   would create an additional attack surface.

Notes
-----
Instead of ignoring attacks, the administrator wants to know when one is taking place, particularly if it is an intense one which would lead to a denial of service, as suggested by the authors. Thus, using a rate-limited logging mechanism is an appropriate solution to keep records of the attack, and to notify the administrator in real-time then he can take actions if he wants to. As there might not be other ways to inform the administrator of an attack taking place, not logging at all is the last choice.
 --VERIFIER NOTES-- 
 We are rejecting because it is not clear what course of action an administrator has when seeing such log messages, so the usefulness of this kind of logging seems marginal at best and the security considerations advice to just silently drop these connections without logging them still seems best.

--------------------------------------
RFC8270 (draft-ietf-curdle-ssh-dh-group-exchange-06)
--------------------------------------
Title               : Increase the Secure Shell Minimum Recommended Diffie-Hellman Modulus Size to 2048 Bits
Publication Date    : December 2017
Author(s)           : L. Velvindron, M. Baushke
Category            : PROPOSED STANDARD
Source              : CURves, Deprecating and a Little more Encryption
Stream              : IETF
Verifying Party     : IESG