Internet Engineering Task Force H. Salgado
Internet-Draft NIC Chile
Intended status: Informational May 8, 2017
Expires: November 9, 2017
The "hxxp" and "hxxps" URI Schemes
draft-salgado-hxxp-01
Abstract
This document describes the "hxxp" and "hxxps" URI schemes, which are
widely used by the security community to obfuscate an http or https
URI to avoid being accidentaly interpreted and loaded by a web
browser or user-agent.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. URI Scheme Specification . . . . . . . . . . . . . . . . . . 3
2.1. URI Scheme Syntax . . . . . . . . . . . . . . . . . . . . 3
2.2. URI Scheme Semantics . . . . . . . . . . . . . . . . . . 3
2.3. Encoding Considerations . . . . . . . . . . . . . . . . . 3
3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4.1. URI Scheme Registration . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
This document describes the "hxxp" and "hxxps" URI schemes, which are
widely used by the security community to obfuscate an http or https
URI to avoid being accidentaly interpreted and loaded by a web
browser or user-agent.
These schemes are used in case the resource is dangerous and there is
security risks on being automatically processed by an application,
such a pre-loading mechanism in web user agents. It also prevents
the creation of "clickables" areas in user interfaces, which could
detect http or https URIs automatically.
The purpose of this registration is to document its use, prevent any
registration of this scheme in the future, explicitly recommend to
web application developers to never act with this URI schemes in any
way, and provide a safe method for the security community to share
malicious information. These schemes must not be treated as an http
or https schemes, and must not be identified as web resources. Its
consumption is only for humans and documentation, and should be
handled with caution by security professionals.
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].
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2. URI Scheme Specification
2.1. URI Scheme Syntax
The "hxxp" URI syntactically conforms to the <hxxp-uri> rule below,
expressed using the Augmented Backus-Naur Form (ABNF) [RFC5234]:
hxxp-uri = "hxxp:" hxxp-token [ hxxp-query ] [ hxxp-fragment ]
hxxp-token = *pchar
hxxp-query = "?" query
hxxp-fragment = "#" fragment
pchar = <as specified in RFC 3986, Appendix A>
query = <as specified in RFC 3986, Appendix A>
fragment = <as specified in RFC 3986, Appendix A>
The "hxxps" URI syntactically conforms to the <hxxps-uri> rule below,
expressed using the Augmented Backus-Naur Form (ABNF) [RFC5234]:
hxxps-uri = "hxxps:" hxxps-token [ hxxps-query ] [ hxxps-fragment ]
hxxps-token = *pchar
hxxps-query = "?" query
hxxps-fragment = "#" fragment
pchar = <as specified in RFC 3986, Appendix A>
query = <as specified in RFC 3986, Appendix A>
fragment = <as specified in RFC 3986, Appendix A>
2.2. URI Scheme Semantics
The resource that is referenced by a particular "hxxp" or "hxxps" URI
is NOT meant to be interpreted or parsed in any way for applications,
or any automated means. The resource MUST be interpreted and
consumed by human security professionals.
2.3. Encoding Considerations
"hxxp" and "hxxps" URIs are subject to encoding rules as defined in
RFC 3986 [RFC3986].
3. Acknowledgements
The author acknowledges the suggestions and comments made by Fernando
Gont and Harlan Lieberman-Berg, for the first revision.
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4. IANA Considerations
4.1. URI Scheme Registration
The IANA is requested to register "hxxp" and "hxxps" URI schemes in
the "Provisional URI Schemes" registry. The information below is
provided according to the guidelines from RFC 7595 [RFC7595]:
-----
Scheme name: hxxp
Status: Provisional
Applications/protocols that use this scheme name: "hxxp" URIs are
forbidden to be used by applications.
Contact: Hugo Salgado <hsalgado@nic.cl>
Change controller: Hugo Salgado <hsalgado@nic.cl>
References: "The "hxxp" and "hxxps" URI Schemes" Internet Draft,
https://datatracker.ietf.org/doc/draft-salgado-hxxp/
-----
-----
Scheme name: hxxps
Status: Provisional
Applications/protocols that use this scheme name: "hxxps" URIs are
forbidden to be used by applications.
Contact: Hugo Salgado <hsalgado@nic.cl>
Change controller: Hugo Salgado <hsalgado@nic.cl>
References: "The "hxxp" and "hxxps" URI Schemes" Internet Draft,
https://datatracker.ietf.org/doc/draft-salgado-hxxp/
-----
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5. Security Considerations
As stated in the Introduction, the "hxxp" and "hxxps" schemes are
forbidden to be used or interpreted by applications. These schemes
must be consumed only by humans.
Application developers are encouraged to forbid "hxxp" and "hxxps"
schemes URIs inside HTML anchors or tags.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<http://www.rfc-editor.org/info/rfc5234>.
6.2. Informative References
[RFC7595] Thaler, D., Ed., Hansen, T., and T. Hardie, "Guidelines
and Registration Procedures for URI Schemes", BCP 35,
RFC 7595, DOI 10.17487/RFC7595, June 2015,
<http://www.rfc-editor.org/info/rfc7595>.
Author's Address
Hugo Salgado
NIC Chile
Miraflores 222, piso 14
Santiago CP 8320198
CL
Phone: +56 2 29407700
Email: hsalgado@nic.cl
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