Deprecate modification of 'secure' cookies from non-secure origins
draft-west-leave-secure-cookies-alone-03

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HTTPbis                                                          M. West
Internet-Draft                                               Google, Inc
Updates: 6265 (if approved)                            November 23, 2015
Intended status: Standards Track
Expires: May 26, 2016

   Deprecate modification of 'secure' cookies from non-secure origins
                draft-west-leave-secure-cookies-alone-03

Abstract

   This document updates RFC6265 by removing the ability for a non-
   secure origin to set cookies with a 'secure' flag, and to overwrite
   cookies whose 'secure' flag is set.  This deprecation improves the
   isolation between HTTP and HTTPS origins, and reduces the risk of
   malicious interference.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 26, 2016.

Copyright Notice

   Copyright (c) 2015 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of

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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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology and notation  . . . . . . . . . . . . . . . . . .   2
   3.  Recommendations . . . . . . . . . . . . . . . . . . . . . . .   2
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Section 8.5 and Section 8.6 of [RFC6265] spell out some of the
   drawbacks of cookies' implementation: due to historical accident,
   non-secure origins can set cookies which will be delivered to secure
   origins in a manner indistinguishable from cookies set by that origin
   itself.  This enables a number of attacks, which have been recently
   spelled out in some detail in [COOKIE-INTEGRITY].

   We can mitigate the risk of these attacks by making it more difficult
   for non-secure origins to influence the state of secure origins.
   Accordingly, this document recommends the deprecation and removal of
   non-secure origins' ability to write cookies with a 'secure' flag,
   and their ability to overwrite cookies whose 'secure' flag is set.

2.  Terminology and notation

   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 [RFC2119].

   The "scheme" component of a URI is defined in Section 3 of [RFC3986].

3.  Recommendations

   This document updates Section 5.3 of [RFC6265] as follows:

   1.  After step 8 of the current algorithm, which sets the cookie's
       "secure-only-flag", execute the following step:

       1.  If the "scheme" component of the "request-uri" does not
           denote a "secure" protocol (as defined by the user agent),

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           and the cookie's "secure-only-flag" is "true", then abort
           these steps and ignore the newly created cookie entirely.

   2.  Before step 11, execute the following step:

       1.  If the newly created cookie's "secure-only-flag" is not set,
           and the "scheme" component of the "request-uri" does not
           denote a "secure" protocol, then abort these steps and ignore
           the newly created cookie entirely if the cookie store