Re: [Acme] tls-sni-01 validation compromise

Thomas Lußnig <lussnig@suche.org> Fri, 22 January 2016 20:30 UTC

Return-Path: <lussnig@suche.org>
X-Original-To: acme@ietfa.amsl.com
Delivered-To: acme@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5B2601A877F for <acme@ietfa.amsl.com>; Fri, 22 Jan 2016 12:30:02 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.251
X-Spam-Level:
X-Spam-Status: No, score=-1.251 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HELO_EQ_DE=0.35, MIME_8BIT_HEADER=0.3, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001] autolearn=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cpsBkZFm3hyn for <acme@ietfa.amsl.com>; Fri, 22 Jan 2016 12:30:01 -0800 (PST)
Received: from relay-mx.smcc.de (relay-mx.smcc.de [194.50.33.90]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 04BF31A8771 for <acme@ietf.org>; Fri, 22 Jan 2016 12:30:00 -0800 (PST)
Received: by mx-32.smcc.de (Postfix, from userid 65534) id B59196528A; Fri, 22 Jan 2016 21:29:58 +0100 (CET)
X-Spam-SCL: 1
Received: from localhost (localhost [127.0.0.1]) by mx-32.smcc.de (Postfix) with ESMTP id 72A4365281 for <acme@ietf.org>; Fri, 22 Jan 2016 21:29:58 +0100 (CET)
X-Virus-Scanned: Debian amavisd-new at mx-30.smcc.net
Received: from relay-mx.smcc.de ([127.0.0.1]) by localhost (relay-mx-02.smcc.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cl9wQFyQ_QdK for <acme@ietf.org>; Fri, 22 Jan 2016 21:29:58 +0100 (CET)
Received: from [192.168.1.3] (ip-37-24-30-28.hsi14.unitymediagroup.de [37.24.30.28]) by mx-32.smcc.de (Postfix) with ESMTPSA id 5682565271 for <acme@ietf.org>; Fri, 22 Jan 2016 21:29:58 +0100 (CET)
To: acme@ietf.org
References: <CAES3dxRZ7ieQ+G0Zv0oZmehUFPGU36KUdvrkSL+MMLSQWbP08w@mail.gmail.com>
From: Thomas Lußnig <lussnig@suche.org>
Message-ID: <56A29147.80601@suche.org>
Date: Fri, 22 Jan 2016 21:29:59 +0100
MIME-Version: 1.0
In-Reply-To: <CAES3dxRZ7ieQ+G0Zv0oZmehUFPGU36KUdvrkSL+MMLSQWbP08w@mail.gmail.com>
Content-Type: text/plain; charset="windows-1252"; format="flowed"
Content-Transfer-Encoding: 7bit
Archived-At: <http://mailarchive.ietf.org/arch/msg/acme/F-yRyYk1dZuB3gGAp8cOAKG1UjA>
Subject: Re: [Acme] tls-sni-01 validation compromise
X-BeenThere: acme@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Automated Certificate Management Environment <acme.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/acme>, <mailto:acme-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/acme/>
List-Post: <mailto:acme@ietf.org>
List-Help: <mailto:acme-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/acme>, <mailto:acme-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 22 Jan 2016 20:30:02 -0000

Hi,

these problem is not new. I raised the roblem with letsencrypt over an 
month ago.
Better Would be:
Client Send clientnone,ECDSA-SHA256(servernonce,clientnonce)

The cert for <fqdn>.challenge.amce contain the public key.
So the client had proved he control the server