[websec] comments on -frame-options and -x-frame-options drafts
Chris Weber <chris@lookout.net> Thu, 19 April 2012 00:27 UTC
Return-Path: <chris@lookout.net>
X-Original-To: websec@ietfa.amsl.com
Delivered-To: websec@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 2053B21F8460 for <websec@ietfa.amsl.com>; Wed, 18 Apr 2012 17:27:50 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.235
X-Spam-Level:
X-Spam-Status: No, score=-2.235 tagged_above=-999 required=5 tests=[AWL=0.365, BAYES_00=-2.599]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 77fX2WA51fiQ for <websec@ietfa.amsl.com>; Wed, 18 Apr 2012 17:27:49 -0700 (PDT)
Received: from n06.mail01.mtsvc.net (mailout08.mail01.mtsvc.net [216.70.64.26]) by ietfa.amsl.com (Postfix) with ESMTP id 989D121F845C for <websec@ietf.org>; Wed, 18 Apr 2012 17:27:49 -0700 (PDT)
Received: from [174.136.108.2] (port=53328 helo=[0.0.0.0]) by n06.mail01.mtsvc.net with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from <chris@lookout.net>) id 1SKfDw-0006uK-Fk for websec@ietf.org; Wed, 18 Apr 2012 20:27:48 -0400
Message-ID: <4F8F5C05.8010904@lookout.net>
Date: Wed, 18 Apr 2012 17:27:49 -0700
From: Chris Weber <chris@lookout.net>
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:11.0) Gecko/20120327 Thunderbird/11.0.1
MIME-Version: 1.0
To: websec <websec@ietf.org>
X-Enigmail-Version: 1.4
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7bit
X-Authenticated-User: 882879 chris@lookout.net
Subject: [websec] comments on -frame-options and -x-frame-options drafts
X-BeenThere: websec@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Web Application Security Minus Authentication and Transport <websec.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/websec>, <mailto:websec-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/websec>
List-Post: <mailto:websec@ietf.org>
List-Help: <mailto:websec-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/websec>, <mailto:websec-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 19 Apr 2012 00:27:50 -0000
Sending this with a new subject as I think my comments could have been better placed. I have one nit with these documents - the way they bring Cross Site Request Forgery (CSRF) into the discussion and positions X-Frame-Options as a "sometimes" mitigation for CSRF. We could probably agree that wording such as "In some forms of Clickjacking and CSRF an attacker tricks a user into clicking..." sufficiently limits the scope of the context. However I feel that CSRF in general is just completely out of scope - there are many attacks that might leverage framing after all. I also worry that some people may be led to believe that the X-Frame-Options header provides general protection from CSRF when that's absolutely not the case. When Microsoft released this functionality with IE8, it was positioned as a protection against framing attacks, or Clickjacking, and not CSRF. I believe that's how many of us in the security community still view it - it's only a protection against CSRF in cases where framing is required to execute the CSRF attack. The two (Clickjacking and CSRF) can only be linked in that and similar contexts. I suggest that references to CSRF protection be removed to avoid confusion or that the wording reflect this narrow scope of the CSRF-protection (preferably the former). After all, CSRF is just one example of many other attacks that could leverage framing - e.g. we could include answering CAPTCHAs, certain forms of self-side XSS, and even information disclosure as equivalent forms of attack (like CSRF) that might leverage framing. Can we keep the documents focused on the primary design goal - controlling/preventing framing - and avoid lumping in other forms of attack that might piggyback on such framing? Best regards, Chris Weber