idnits 2.17.1 draft-gondrom-x-frame-options-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (March 5, 2012) is 4428 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Missing Reference: 'TBD' is mentioned on line 227, but not defined == Unused Reference: 'CLICK-DEFENSE-BLOG' is defined on line 299, but no explicit reference was found in the text -- Obsolete informational reference (is this intentional?): RFC 822 (Obsoleted by RFC 2822) -- Obsolete informational reference (is this intentional?): RFC 2616 (Obsoleted by RFC 7230, RFC 7231, RFC 7232, RFC 7233, RFC 7234, RFC 7235) Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 WEBSEC D. Ross 3 Internet-Draft Microsoft 4 Intended status: Informational T. Gondrom 5 Expires: September 6, 2012 March 5, 2012 7 HTTP Header X-Frame-Options 8 draft-gondrom-x-frame-options-00 10 Abstract 12 To improve the protection of web applications against Cross Site 13 Request Forgery (CSRF) and Clickjacking this standards defines a http 14 response header that declares a policy communicated from a host to 15 the client browser whether the transmitted content MUST NOT be 16 displayed in frames of other pages from different origins or a list 17 of trusted origins which are allowed to frame the content. This 18 drafts serves to document the existing use and specification of 19 X-Frame-Options. 21 Status of this Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at http://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on September 6, 2012. 38 Copyright Notice 40 Copyright (c) 2012 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (http://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 56 1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3 57 2. Frame-Options Header . . . . . . . . . . . . . . . . . . . . . 3 58 2.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 2.2. Backus-Naur Form (BNF) . . . . . . . . . . . . . . . . . . 5 60 2.3. Design Issues . . . . . . . . . . . . . . . . . . . . . . . 5 61 2.3.1. Enable HTML content from other domains . . . . . . . . 5 62 2.3.2. Browser Behaviour and Processing . . . . . . . . . . . 5 63 2.4. Examples of Frame-Options Headers . . . . . . . . . . . . . 6 64 2.4.1. Example scenario for the ALLOW-FROM parameter . . . . . 6 65 3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 66 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 67 4.1. Registration Template . . . . . . . . . . . . . . . . . . . 7 68 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 69 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 70 6.1. Normative References . . . . . . . . . . . . . . . . . . . 7 71 6.2. Informative References . . . . . . . . . . . . . . . . . . 7 72 Appendix A. Description of a Clickjacking attack . . . . . . . . . 8 73 A.1. Shop . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 74 A.2. Confirm Purchase Page . . . . . . . . . . . . . . . . . . . 9 75 A.3. Flash Configuration . . . . . . . . . . . . . . . . . . . . 9 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 78 1. Introduction 80 In 2009 and 2010 many browser vendors introduced the use of a non- 81 standard http header RFC 2616 [RFC2616] "X-Frame-Options" to protect 82 against Clickjacking [Clickjacking] and Cross Site Request Forgery 83 (CSRF) [CSRF]. This draft is to document the current use of X-Frame- 84 Options header and shall in the future be replaced by the Frame- 85 Options (CSRF) [FRAME-OPTIONS] standard. 87 In some forms of Clickjacking and CSRF an attacker tricks a user into 88 clicking on a button or link to another page and by thus executing an 89 unintended command in the context of a different web application. 90 For example with Clickjacking the attacker might use transparent or 91 opaque layers to integrate and obscure a button to another page so 92 that the user may click on it in the expectation of a different 93 action. So, in this way the attacker is "hijacking" the "Click" on a 94 button meant by the user to be sent to host A, while clicking the 95 button in effect sends a message to host B. If the user does for 96 example also have an open session with host B this can lead to a CSRF 97 attack and executing a command in the session context of the user 98 (using the user's authentication and authorization) on host B without 99 his intention or knowledge. 101 Existing anti-ClickJacking measures, e.g. Frame-breaking Javascript, 102 have weaknesses so that their protection can be circumvented as a 103 study [FRAME-BUSTING] demonstrated. 105 Short of configuring the browser to disable frames and script 106 entirely, which massively impairs browser utility, browser users are 107 vulnerable to this type of attack. 109 The by "Frame-Options" provided defense mechanism against 110 Clickjacking is to allow a secure web page from host B to declare 111 that its content (for example a button, links, text, etc.) must not 112 be displayed in a frame of another page (e.g. from host A). In 113 principle this is done by a policy declared in the HTTP header and 114 obeyed by conform browser implementations. 116 1.1. Requirements Language 118 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 119 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 120 document are to be interpreted as described in RFC 2119 [RFC2119]. 122 2. Frame-Options Header 124 The Frame-Options HTTP response header indicates a policy whether a 125 browser MUST NOT allow to render a page in a or