From: Cameron Garnham <da2ce7@gmail.com>
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Date: Fri, 26 May 2017 09:30:08 +0300
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: [bitcoin-dev] Emergency Deployment of SegWit as a partial
 mitigation of CVE-2017-9230
Precedence: list

Hello Bitcoin-Dev,

CVE-2017-9230 (1) (2), or commonly known as =E2=80=98ASICBOOST=E2=80=99 =
is a severe (3) (4) and actively exploited (5) security vulnerability.
=20
To learn more about this vulnerability please read Jeremy Rubin=E2=80=99s =
detailed report:
http://www.mit.edu/~jlrubin//public/pdfs/Asicboost.pdf
=20
Andreas Antonopoulos has an excellent presentation on why asicboost is =
dangerous:
https://www.youtube.com/watch?v=3Dt6jJDD2Aj8k

In decisions on the #bitcoin-core-dev IRC channel; It was proposed, =
without negative feedback, that SegWit be used as a partial-mitigation =
of CVE-2017-9230.

SegWit partially mitigates asicboost with the common reasonable =
assumption that any block that doesn=E2=80=99t include a witness commit =
in it's coinbase transaction was mined using covert asicboost.  Making =
the use of covert asicboost far more conspicuous.

It was also proposed that this partial mitigation should be quickly =
strengthened via another soft-fork that makes the inclusion of witness =
commits mandatory, without negative feedback.

The security trade-offs of deploying a partial-mitigation to =
CVE-2017-9230 quickly vs more slowly but more conservatively is under =
intense debate.  The author of this post has a strong preference to the =
swiftest viable option.

Cameron.


(1) CVE Entry:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=3D+CVE-2017-9230

(2) Announcement of CVE to Mailing List:
=
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-May/014416.ht=
ml

(3) Discussion of the perverse incentives created by 'ASICBOOST' by Ryan =
Grant:
 =
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-May/014352.ht=
ml

(4) Discussion of ASICBOOST's non-independent PoW calculation by Tier =
Nolan:
 =
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-May/014351.ht=
ml

(5) Evidence of Active Exploit by Gregory Maxwell:
=
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-April/013996.=
html