WEBSEC D. Ross
Internet-Draft Microsoft
Intended status: Informational T. Gondrom
Expires: January 4, 2013 July 3, 2012
HTTP Header X-Frame-Options
draft-ietf-websec-x-frame-options-00
Abstract
To improve the protection of web applications against Clickjacking
this standards defines a http response header that declares a policy
communicated from a host to the client browser whether the
transmitted content MUST NOT be displayed in frames of other pages
from different origins which are allowed to frame the content. This
drafts serves to document the existing use and specification of
X-Frame-Options.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 4, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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include Simplified BSD License text as described in Section 4.e of
Ross & Gondrom Expires January 4, 2013 [Page 1]
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3
2. X-Frame-Options Header . . . . . . . . . . . . . . . . . . . . 3
2.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Backus-Naur Form (BNF) . . . . . . . . . . . . . . . . . . 4
2.3. Design Issues . . . . . . . . . . . . . . . . . . . . . . . 5
2.3.1. Enable HTML content from other domains . . . . . . . . 5
2.3.2. Browser Behaviour and Processing . . . . . . . . . . . 5
2.4. Examples of X-Frame-Options Headers . . . . . . . . . . . . 5
2.4.1. Example scenario for the ALLOW-FROM parameter . . . . . 6
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Registration Template . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6.1. Normative References . . . . . . . . . . . . . . . . . . . 7
6.2. Informative References . . . . . . . . . . . . . . . . . . 7
Appendix A. Description of a Clickjacking attack . . . . . . . . . 8
A.1. Shop . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
A.2. Confirm Purchase Page . . . . . . . . . . . . . . . . . . . 8
A.3. Flash Configuration . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
In 2009 and 2010 many browser vendors introduced the use of a non-
standard http header RFC 2616 [RFC2616] "X-Frame-Options" to protect
against Clickjacking [Clickjacking]. This draft is to document the
current use of X-Frame-Options header and shall in the future be
replaced by the Frame-Options (CSRF) [FRAME-OPTIONS] standard.
Existing anti-ClickJacking measures, e.g. Frame-breaking Javascript,
have weaknesses so that their protection can be circumvented as a
study [FRAME-BUSTING] demonstrated.
Short of configuring the browser to disable frames and script
entirely, which massively impairs browser utility, browser users are
vulnerable to this type of attack.
The "X-Frame-Options" allows a secure web page from host B to declare
that its content (for example a button, links, text, etc.) must not
be displayed in a frame of another page (e.g. from host A). In
principle this is done by a policy declared in the HTTP header and
obeyed by conform browser implementations.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. X-Frame-Options Header
The X-Frame-Options HTTP response header indicates a policy whether a
browser MUST NOT allow to render a page in a or