A File Format to Aid in Security Vulnerability Disclosure
draft-foudil-securitytxt-10

Document Type Active Internet-Draft (individual in sec area)
Authors Edwin Foudil  , Yakov Shafranovich 
Last updated 2020-08-23
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Network Working Group                                          E. Foudil
Internet-Draft                                                          
Intended status: Informational                           Y. Shafranovich
Expires: 24 February 2021                       Nightwatch Cybersecurity
                                                          23 August 2020

       A File Format to Aid in Security Vulnerability Disclosure
                      draft-foudil-securitytxt-10

Abstract

   When security vulnerabilities are discovered by researchers, proper
   reporting channels are often lacking.  As a result, vulnerabilities
   may be left unreported.  This document defines a format
   ("security.txt") to help organizations describe their vulnerability
   disclosure practices to make it easier for researchers to report
   vulnerabilities.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://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 24 February 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://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 the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Motivation, Prior Work and Scope  . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Note to Readers . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  The Specification . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Scope of the File . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Comments  . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.3.  Line Separator  . . . . . . . . . . . . . . . . . . . . .   6
     3.4.  Digital signature . . . . . . . . . . . . . . . . . . . .   6
     3.5.  Field Definitions . . . . . . . . . . . . . . . . . . . .   7
       3.5.1.  Acknowledgments . . . . . . . . . . . . . . . . . . .   7
       3.5.2.  Canonical . . . . . . . . . . . . . . . . . . . . . .   7
       3.5.3.  Contact . . . . . . . . . . . . . . . . . . . . . . .   8
       3.5.4.  Encryption  . . . . . . . . . . . . . . . . . . . . .   8
       3.5.5.  Expires . . . . . . . . . . . . . . . . . . . . . . .   9
       3.5.6.  Hiring  . . . . . . . . . . . . . . . . . . . . . . .   9
       3.5.7.  Policy  . . . . . . . . . . . . . . . . . . . . . . .   9
       3.5.8.  Preferred-Languages . . . . . . . . . . . . . . . . .   9
     3.6.  Example of an unsigned "security.txt" file  . . . . . . .  10
     3.7.  Example of a signed "security.txt" file . . . . . . . . .  10
   4.  Location of the security.txt file . . . . . . . . . . . . . .  11
     4.1.  Web-based services  . . . . . . . . . . . . . . . . . . .  11
     4.2.  Filesystems . . . . . . . . . . . . . . . . . . . . . . .  11
     4.3.  Extensibility . . . . . . . . . . . . . . . . . . . . . .  11
   5.  File Format Description and ABNF Grammar  . . . . . . . . . .  12
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
     6.1.  Compromised Files and Incident Response . . . . . . . . .  13
     6.2.  Redirects . . . . . . . . . . . . . . . . . . . . . . . .  14
     6.3.  Incorrect or Stale Information  . . . . . . . . . . . . .  14
     6.4.  Intentionally Malformed Files, Resources and Reports  . .  14
     6.5.  No Implied Permission for Testing . . . . . . . . . . . .  15
     6.6.  Multi-user Environments . . . . . . . . . . . . . . . . .  15
     6.7.  Protecting Data in Transit  . . . . . . . . . . . . . . .  15
     6.8.  Spam and Spurious Reports . . . . . . . . . . . . . . . .  16
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
     7.1.  Well-Known URIs registry  . . . . . . . . . . . . . . . .  17
     7.2.  Registry for security.txt Fields  . . . . . . . . . . . .  17

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   8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  19
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  19
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  19
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  21
   Appendix A.  Note to Readers  . . . . . . . . . . . . . . . . . .  22
   Appendix B.  Document History . . . . . . . . . . . . . . . . . .  22
     B.1.  Since draft-foudil-securitytxt-00 . . . . . . . . . . . .  23
     B.2.  Since draft-foudil-securitytxt-01 . . . . . . . . . . . .  23
     B.3.  Since draft-foudil-securitytxt-02 . . . . . . . . . . . .  23
     B.4.  Since draft-foudil-securitytxt-03 . . . . . . . . . . . .  24
     B.5.  Since draft-foudil-securitytxt-04 . . . . . . . . . . . .  24
     B.6.  Since draft-foudil-securitytxt-05 . . . . . . . . . . . .  25
     B.7.  Since draft-foudil-securitytxt-06 . . . . . . . . . . . .  25
     B.8.  Since draft-foudil-securitytxt-07 . . . . . . . . . . . .  25
     B.9.  Since draft-foudil-securitytxt-08 . . . . . . . . . . . .  26
     B.10. Since draft-foudil-securitytxt-09 . . . . . . . . . . . .  26
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  26

1.  Introduction

1.1.  Motivation, Prior Work and Scope

   Many security researchers encounter situations where they are unable
   to report security vulnerabilities to organizations because there are
   no reporting channels to contact the owner of a particular resource
   and no information available about the vulnerability disclosure
   practices of such owner.

   As per section 4 of [RFC2142], there is an existing convention of
   using the <SECURITY@domain> email address for communications
   regarding security vulnerabilities.  That convention provides only a
   single, email-based channel of communication for security
   vulnerabilities per domain, and does not provide a way for domain
   owners to publish information about their security disclosure
   practices.

   There are also contact conventions prescribed for Internet Service
   Providers (ISPs) in section 2 of [RFC3013], for Computer Security
   Incident Response Teams (CSIRTs) in section 3.2 of [RFC2350] and for
   site operators in section 5.2 of [RFC2196].  As per [RFC7485], there
   is also contact information provided by Regional Internet Registries
   (RIRs) and domain registries for owners of IP addresses, autonomous
   system numbers (ASNs), and domain names.  However, none of these
   address the issue of how security researchers can locate contact
   information and vulnerability disclosure practices for organizations
   in order to report vulnerabilities.

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   In this document, we define a richer and more extensible way for
   organizations to communicate information about their security
   disclosure practices and ways to contact them.  Other details of
   vulnerability disclosure are outside the scope of this document.
   Readers are encouraged to consult other documents such as
   [ISO.29147.2018] or [CERT.CVD].

   As per [CERT.CVD], "vulnerability response" refers to reports of
   product vulnerabilities which is related but distinct from reports of
   network intrusions and compromised websites ("incident response").
   The mechanism defined in this document is intended to be used for the
   former ("vulnerability response").  If implementors want to utilize
   this mechanism for incident response, they should be aware of
   additional security considerations discussed in Section 6.1.

   The "security.txt" file is intended to be complementary and not as a
   substitute or replacement for other public resources maintained by
   organizations regarding their security disclosure practices.

1.2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Note to Readers

      *Note to the RFC Editor:* Please remove this section prior to
      publication.

   Development of this draft takes place on Github at:
   https://github.com/securitytxt/security-txt

3.  The Specification

   This document defines a text file to be placed in a known location
   that provides information about the vulnerability disclosure
   practices of a particular organization.  This is intended to help
   security researchers when disclosing security vulnerabilities.

   By convention, the file is named "security.txt".

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   When made available on HTTP servers, it MUST be placed under the
   /.well-known/ path (as "/.well-known/security.txt") [RFC8615] of a
   domain name or IP address.  For legacy compatibility, a security.txt
   file might be placed at the top level path (see Section 4.1).  For
   file systems a "security.txt" file SHOULD be placed in the root
   directory of the file system.

   On HTTP servers, the file MUST be accessed via HTTP 1.0 or a higher
   version and the "https" scheme (as per [RFC1945] and section 2.7.2 of
   [RFC7230]).  It MUST have a Content-Type of "text/plain" with the
   default charset parameter set to "utf-8" (as per section 4.1.3 of
   [RFC2046]).

   This text file contains multiple fields with different values.  A
   field contains a "name" which is the first part of a field all the
   way up to the colon ("Contact:") and follows the syntax defined for
   "field-name" in section 3.6.8 of [RFC5322].  Field names are case-
   insensitive (as per section 2.3 of [RFC5234]).  The "value" comes
   after the field name ("https://example.com/security") and follows the
   syntax defined for "unstructured" in section 3.2.5 of [RFC5322].  The
   file may also contain blank lines.

   A "field" MUST always consist of a name and a value ("Contact:
   https://example.com/security").  A security.txt file can have an
   unlimited number of fields.  It is important to note that each field
   MUST appear on its own line.  Unless specified otherwise by the field
   definition, multiple values MUST NOT be chained together for a single
   field.  Unless otherwise indicated in a definition of a particular
   field, any field MAY appear multiple times.

   Implementors should be aware that some of the fields may contain URIs
   using percent-encoding (as per section 2.1 of [RFC3986]).

3.1.  Scope of the File

   For HTTP servers, a "security.txt" file MUST only apply to the domain
   or IP address in the URI used to retrieve it, not to any of its
   subdomains or parent domains.

   A "security.txt" file that is found in a file system MUST only apply
   to the folder in which it is located and that folder's subfolders.
   The file does not apply to any of the folder's parent or sibling
   folders.

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   A "security.txt" file MAY also apply to products and services
   provided by the organization publishing the file.  Implementors
   SHOULD use the policy directive (as per Section 3.5.7) to provide
   additional details regarding scope and details of their vulnerability
   disclosure process.

   Some examples appear below:

   # The following only applies to example.com.
   https://example.com/.well-known/security.txt

   # This only applies to subdomain.example.com.
   https://subdomain.example.com/.well-known/security.txt

   # This security.txt file applies to IPv4 address of 192.0.2.0.
   https://192.0.2.0/.well-known/security.txt

   # This security.txt file applies to IPv6 address of 2001:db8:8:4::2.
   https://[2001:db8:8:4::2]/.well-known/security.txt

   # This file applies to the /example/folder1 directory and subfolders.
   /example/folder1/security.txt

3.2.  Comments

   Any line beginning with the "#" (%x30) symbol MUST be interpreted as
   a comment.  The content of the comment may contain any ASCII or
   Unicode characters in the %x21-7E and %x80-FFFFF ranges plus the tab
   (%x09) and space (%x20) characters.

   Example:

   # This is a comment.

3.3.  Line Separator

   Every line MUST end either with a carriage return and line feed
   characters (CRLF / %x0D %x0A) or just a line feed character (LF /
   %x0A).

3.4.  Digital signature

   It is RECOMMENDED that a security.txt file be digitally signed using
   an OpenPGP cleartext signature as described in section 7 of
   [RFC4880].  When digital signatures are used, it is also RECOMMENDED
   that implementors use the "Canonical" field (as per Section 3.5.2),
   thus allowing the digital signature to authenticate the location of
   the file.

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   When it comes to verifying the key used to generate the signature, it
   is always the security researcher's responsibility to make sure the
   key being used is indeed one they trust.

3.5.  Field Definitions

3.5.1.  Acknowledgments

   This field indicates a link to a page where security researchers are
   recognized for their reports.  The page being referenced should list
   individuals or organizations that reported security vulnerabilities
   and collaborated to remediate them.  Organizations should be careful
   to limit the vulnerability information being published in order to
   prevent future attacks.

   If this field indicates a web URL, then it MUST begin with "https://"
   (as per section 2.7.2 of [RFC7230]).

   Example:

   Acknowledgments: https://example.com/hall-of-fame.html

   Example security acknowledgments page:

   We would like to thank the following researchers:

   (2017-04-15) Frank Denis - Reflected cross-site scripting
   (2017-01-02) Alice Quinn  - SQL injection
   (2016-12-24) John Buchner - Stored cross-site scripting
   (2016-06-10) Anna Richmond - A server configuration issue

3.5.2.  Canonical

   This field indicates the canonical URIs where the security.txt file
   is located, which is usually something like
   "https://example.com/.well-known/security.txt".  If this field
   indicates a web URL, then it MUST begin with "https://" (as per
   section 2.7.2 of [RFC7230]).  The purpose of this field is to allow a
   digital signature to be applied to the locations of the
   "security.txt" file.

   Canonical: https://www.example.com/.well-known/security.txt
   Canonical: https://someserver.example.com/.well-known/security.txt

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3.5.3.  Contact

   This field indicates an address that researchers should use for
   reporting security vulnerabilities such as an email address, a phone
   number and/or a web page with contact information.  The "Contact"
   field MUST always be present in a security.txt file.  If this field
   indicates a web URL, then it MUST begin with "https://" (as per
   section 2.7.2 of [RFC7230]).  Security email addresses should use the
   conventions defined in section 4 of [RFC2142].

   The value MUST follow the URI syntax described in [RFC3986].  This
   means that "mailto" and "tel" URI schemes must be used when
   specifying email addresses and telephone numbers, as defined in
   [RFC6068] and [RFC3966].  When the value of this field is an email
   address, it is RECOMMENDED that encryption be used (as per
   Section 3.5.4).

   The precedence SHOULD be in listed order.  The first field is the
   preferred method of contact.  In the example below, the email address
   is the preferred method of contact.

   Contact: mailto:security@example.com
   Contact: mailto:security%2Buri%2Bencoded@example.com
   Contact: tel:+1-201-555-0123
   Contact: https://example.com/security-contact.html

3.5.4.  Encryption

   This field indicates an encryption key that security researchers
   should use for encrypted communication.  Keys MUST NOT appear in this
   field - instead the value of this field MUST be a URI pointing to a
   location where the key can be retrieved.  If this field indicates a
   web URL, then it MUST begin with "https://" (as per section 2.7.2 of
   [RFC7230]).

   When it comes to verifying the authenticity of the key, it is always
   the security researcher's responsibility to make sure the key being
   specified is indeed one they trust.  Researchers must not assume that
   this key is used to generate the digital signature referenced in
   Section 3.4.

   Example of an OpenPGP key available from a web server:

   Encryption: https://example.com/pgp-key.txt

   Example of an OpenPGP key available from an OPENPGPKEY DNS record:

Encryption: dns:5d2d37ab76d47d36._openpgpkey.example.com?type=OPENPGPKEY

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   Example of an OpenPGP key being referenced by its fingerprint:

   Encryption: openpgp4fpr:5f2de5521c63a801ab59ccb603d49de44b29100f

3.5.5.  Expires

   This field indicates the date and time after which the data contained
   in the "security.txt" file is considered stale and should not be used
   (as per Section 6.3).  The value of this field follows the format
   defined in section 3.3 of [RFC5322].  It is RECOMMENDED that the
   value of this field be less than a year into the future to avoid
   staleness.

   This field MUST always be present and MUST NOT appear more than once.

   Expires: Thu, 31 Dec 2020 18:37:07 -0800

3.5.6.  Hiring

   The "Hiring" field is used for linking to the vendor's security-
   related job positions.  If this field indicates a web URL, then it
   MUST begin with "https://" (as per section 2.7.2 of [RFC7230]).

   Hiring: https://example.com/jobs.html

3.5.7.  Policy

   This field indicates a link to where the vulnerability disclosure
   policy is located.  This can help security researchers understand the
   organization's vulnerability reporting practices.  If this field
   indicates a web URL, then it MUST begin with "https://" (as per
   section 2.7.2 of [RFC7230]).

   Example:

   Policy: https://example.com/disclosure-policy.html

3.5.8.  Preferred-Languages

   This field can be used to indicate a set of natural languages that
   are preferred when submitting security reports.  This set MAY list
   multiple values, separated by commas.  If this field is included then
   at least one value MUST be listed.  The values within this set are
   language tags (as defined in [RFC5646]).  If this field is absent,
   security researchers may assume that English is the language to be
   used (as per section 4.5 of [RFC2277]).

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   The order in which they appear MUST NOT be interpreted as an
   indication of priority - rather these MUST be interpreted as all
   being of equal priority.

   This field MUST NOT appear more than once.

   Example (English, Spanish and French):

   Preferred-Languages: en, es, fr

3.6.  Example of an unsigned "security.txt" file

   # Our security address
   Contact: mailto:security@example.com

   # Our OpenPGP key
   Encryption: https://example.com/pgp-key.txt

   # Our security policy
   Policy: https://example.com/security-policy.html

   # Our security acknowledgments page
   Acknowledgments: https://example.com/hall-of-fame.html

3.7.  Example of a signed "security.txt" file

   ----BEGIN PGP SIGNED MESSAGE-----
   Hash: SHA256

   # Canonical URL
   Canonical: https://example.com/.well-known/security.txt

   # Our security address
   Contact: mailto:security@example.com

   # Our OpenPGP key
   Encryption: https://example.com/pgp-key.txt

   # Our security policy
   Policy: https://example.com/security-policy.html

   # Our security acknowledgments page
   Acknowledgments: https://example.com/hall-of-fame.html
   -----BEGIN PGP SIGNATURE-----
   Version: GnuPG v2.2

   [signature]
   -----END PGP SIGNATURE-----

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4.  Location of the security.txt file

4.1.  Web-based services

   Web-based services MUST place the security.txt file under the
   "/.well-known/" path; e.g. https://example.com/.well-known/
   security.txt as per [RFC8615].  For legacy compatibility, a
   security.txt file might be placed at the top-level path or redirect
   (as per section 6.4 of [RFC7231]) to the security.txt file under the
   "/.well-known/" path.  If a "security.txt" file is present in both
   locations, the one in the "/.well-known/" path MUST be used.

   Retrieval of "security.txt" files and resources indicated within such
   files may result in a redirect (as per section 6.4 of [RFC7231]).
   Researchers should perform additional triage (as per Section 6.2) to
   make sure these redirects are not malicious or pointing to resources
   controlled by an attacker.

4.2.  Filesystems

   File systems SHOULD place the "security.txt" file under the root
   directory; e.g., "/security.txt", "C:\security.txt".

   Example file system:

   /example-directory-1/
   /example-directory-2/
   /example-directory-3/
   /example-file
   /security.txt

4.3.  Extensibility

   Like many other formats and protocols, this format may need to be
   extended over time to fit the ever-changing landscape of the
   Internet.  Therefore, extensibility is provided via an IANA registry
   for fields as defined in Section 7.2.  Any fields registered via that
   process MUST be considered optional.  To encourage extensibility and
   interoperability, implementors MUST ignore any fields they do not
   explicitly support.

   In general, implementors should "be conservative in what you do, be
   liberal in what you accept from others" (as per [RFC0793]).

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5.  File Format Description and ABNF Grammar

   The expected file format of the security.txt file is plain text (MIME
   type "text/plain") as defined in section 4.1.3 of [RFC2046] and is
   encoded using UTF-8 [RFC3629] in Net-Unicode form [RFC5198].

   The following is an ABNF definition of the security.txt format, using
   the conventions defined in [RFC5234].

  body             =  signed / unsigned

  signed           =  sign-header unsigned sign-footer

  sign-header      =  < headers and line from section 7 of [RFC4880] >

  sign-footer      =  < OpenPGP signature from section 7 of [RFC4880] >

  unsigned         =  *line (contact-field eol)
                      *line (expires-field eol)
                      *line [lang-field eol] *line
                      ; order of fields within the file is not important

  line             =  [ (field / comment) ] eol

  eol              =  *WSP [CR] LF

  field            =  ack-field /
                      can-field /
                      contact-field /
                      encryption-field /
                      hiring-field /
                      policy-field /
                      ext-field

  fs               =  ":"

  comment          =  "#" *(WSP / VCHAR / %x80-FFFFF)

  ack-field        =  "Acknowledgments" fs SP uri

  can-field        =  "Canonical" fs SP uri

  contact-field    =  "Contact" fs SP uri

  expires-field    =  "Expires" fs SP date-time

  encryption-field =  "Encryption" fs SP uri

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  hiring-field     =  "Hiring" fs SP uri

  lang-field       =  "Preferred-Languages" fs SP lang-values

  policy-field     =  "Policy" fs SP uri

  date-time        =  < imported from section 3.3 of [RFC5322] >

  lang-tag         =  < Language-Tag from section 2.1 of [RFC5646] >

  lang-values      =  lang-tag *(*WSP "," *WSP lang-tag)

  uri              =  < URI as per [RFC3986] >

  ext-field        =  field-name fs SP unstructured

  field-name       =  < imported from section 3.6.8 of [RFC5322] >

  unstructured     =  < imported from section 3.2.5 of [RFC5322] >

   "ext-field" refers to extension fields, which are discussed in
   Section 4.3

6.  Security Considerations

   In addition to the security considerations of [RFC8615], the
   following considerations apply.

6.1.  Compromised Files and Incident Response

   An attacker that has compromised a website is able to compromise the
   "security.txt" file as well or setup a redirect to their own site.
   This can result in security reports not being received by the
   organization or sent to the attacker.

   To protect against this, organizations should use the "Canonical"
   field to indicate the locations of the file (as per Section 3.5.2),
   digitally sign their "security.txt" files (as per Section 3.4), and
   regularly monitor the file and the referenced resources to detect
   tampering.

   Security researchers should triage the "security.txt" file including
   verifying the digital signature and checking any available historical
   records before using the information contained in the file.  If the
   "security.txt" file looks suspicious or compromised, it should not be
   used.

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   While it is not recommended, implementors may choose to use the
   information published within a "security.txt" file for incident
   response.  In such cases, extreme caution should be taken before
   trusting such information, since it may have been compromised by an
   attacker.  Implementors should use additional methods to verify such
   data including out of band verification of the PGP signature, DNS-
   based approaches, etc.

6.2.  Redirects

   When retrieving the file and any resources referenced in the file,
   researchers should record any redirects since they can lead to a
   different domain or IP address controlled by an attacker.  Further
   inspections of such redirects is recommended before using the
   information contained within the file.

6.3.  Incorrect or Stale Information

   If information and resources referenced in a "security.txt" file are
   incorrect or not kept up to date, this can result in security reports
   not being received by the organization or sent to incorrect contacts,
   thus exposing possible security issues to third parties.  Not having
   a security.txt file may be preferable to having stale information in
   this file.  Organizations must use the "Expires" field (see
   Section 3.5.5) to indicate to researchers when the data in the file
   is no longer valid.

   Organizations should ensure that information in this file and any
   referenced resources such as web pages, email addresses, and
   telephone numbers are kept current, are accessible, controlled by the
   organization, and are kept secure.

6.4.  Intentionally Malformed Files, Resources and Reports

   It is possible for compromised or malicious sites to create files
   that are extraordinarily large or otherwise malformed in an attempt
   to discover or exploit weaknesses in parsing code.  Implementors
   should make sure that any such code is robust against large or
   malformed files and fields and may choose not to parse files larger
   than 32 KBs, having fields longer than 2,048 characters or containing
   more than 1,000 lines.  The ABNF grammar (as defined in Section 5)
   can also be used as a way to verify these files.

   The same concerns apply to any other resources referenced within
   security.txt files, as well as any security reports received as a
   result of publishing this file.  Such resources and reports may be
   hostile, malformed or malicious.

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6.5.  No Implied Permission for Testing

   The presence of a security.txt file might be interpreted by
   researchers as providing permission to do security testing against
   that asset.  This might result in increased testing against an
   organization by researchers.  On the other hand, a decision not to
   publish a security.txt file might be interpreted by the organization
   operating that website to be a way to signal to researchers that
   permission to test that particular site or project is denied.  This
   might result in pushback against researchers reporting security
   issues to that organization.

   Therefore, implementors shouldn't assume that presence or absence of
   a "security.txt" file grants or denies permission for security
   testing.  Any such permission may be indicated in the company's
   vulnerability disclosure policy (as per Section 3.5.7) or a new field
   (as per Section 4.3).

6.6.  Multi-user Environments

   In multi-user / multi-tenant environments, it may possible for a user
   to take over the location of the "security.txt" file.  Organizations
   should reserve the "security.txt" namespace at the root to ensure no
   third-party can create a page with the "security.txt" AND "/.well-
   known/security.txt" names.

6.7.  Protecting Data in Transit

   To protect a "security.txt" file from being tampered with in transit,
   implementors should use HTTPS (as per [RFC2818]) when serving the
   file itself and for retrieval of any web URLs referenced in it
   (except when otherwise noted in this specification).  As part of the
   TLS handshake, implementors should validate the provided X.509
   certificate in accordance with [RFC6125] and the following
   considerations:

   *  Matching is performed only against the DNS-ID identifiers.

   *  DNS domain names in server certificates MAY contain the wildcard
      character '*' as the complete left-most label within the
      identifier.

   The certificate may also be checked for revocation via the Online
   Certificate Status Protocol (OCSP) [RFC6960], certificate revocation
   lists (CRLs), or similar mechanisms.

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   In cases where the "security.txt" file cannot be served via HTTPS
   (such as a filesystem or localhost) or is being served with an
   invalid certificate, additional human triage is recommended since the
   contents may have been modified while in transit.

   As an additional layer of protection, it is also recommended that
   organizations digitally sign their "security.txt" file with OpenPGP
   (as per Section 3.4).  Also, to protect security reports from being
   tampered with or observed while in transit, organizations should
   specify encryption keys (as per Section 3.5.4) unless HTTPS is being
   used for report submission.

   However, the determination of validity of such keys is out of scope
   for this specification.  Security researchers need to establish other
   secure means to verify them.

6.8.  Spam and Spurious Reports

   Similar to concerns in [RFC2142], denial of service attacks via spam
   reports would become easier once a "security.txt" file is published
   by an organization.  In addition, there is an increased likelihood of
   reports being sent in an automated fashion and/or as result of
   automated scans without human triage.  Attackers can also use this
   file as a way to spam unrelated third parties by listing their
   resources and/or contact information.

   Organizations need to weigh the advantages of publishing this file
   versus the possible disadvantages and increased resources required to
   triage security reports.

   Security researchers should review all information within the
   "security.txt" file before submitting reports in an automated fashion
   or as resulting from automated scans.

7.  IANA Considerations

   example.com is used in this document following the uses indicated in
   [RFC2606].

   192.0.2.0 and 2001:db8:8:4::2 are used in this document following the
   uses indicated in [RFC6890].

   Implementors should be aware that any resources referenced within a
   security.txt file MUST NOT point to the Well-Known URIs namespace
   unless they are registered with IANA (as per [RFC8615]).

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7.1.  Well-Known URIs registry

   The "Well-Known URIs" registry should be updated with the following
   additional values (using the template from [RFC8615]):

   URI suffix: security.txt

   Change controller: IETF

   Specification document(s): this document

   Status: permanent

7.2.  Registry for security.txt Fields

   IANA is requested to create the "security.txt Fields" registry in
   accordance with [RFC8126].  This registry will contain fields for use
   in security.txt files, defined by this specification.

   New registrations or updates MUST be published in accordance with the
   "Expert Review" guidelines as described in sections 4.5 and 5 of
   [RFC8126].  Any new field thus registered is considered optional by
   this specification unless a new version of this specification is
   published.

   Designated Experts are expected to check whether a proposed
   registration or update makes sense in the context of industry
   accepted vulnerability disclosure processes such as [ISO.29147.2018]
   and [CERT.CVD], and provides value to organizations and researchers
   using this format.

   New registrations and updates MUST contain the following information:

   1.  Name of the field being registered or updated

   2.  Short description of the field

   3.  Whether the field can appear more than once

   4.  The document in which the specification of the field is published
       (if available)

   5.  New or updated status, which MUST be one of:

       *  current: The field is in current use

       *  deprecated: The field is in current use, but its use is
          discouraged

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       *  historic: The field is no longer in current use

   6.  Change controller

   An update may make a notation on an existing registration indicating
   that a registered field is historical or deprecated if appropriate.

   The initial registry contains these values:

   Field Name: Acknowledgments
   Description: link to page where security researchers are recognized
   Multiple Appearances: Yes
   Published in: this document
   Status: current
   Change controller: IESG

   Field Name: Canonical
   Description: canonical URL for this file
   Multiple Appearances: No
   Published in: this document
   Status: current
   Change controller: IESG

   Field Name: Contact
   Description: contact information to use for reporting vulnerabilities
   Multiple Appearances: Yes
   Published in: this document
   Status: current
   Change controller: IESG

   Field Name: Expires
   Description: date and time after which this file is considered stale
   Multiple Appearances: No
   Published in: this document
   Status: current
   Change controller: IESG

   Field Name: Encryption
   Description: link to a key to be used for encrypted communication
   Multiple Appearances: Yes
   Published in: this document
   Status: current
   Change controller: IESG

   Field Name: Hiring
   Description: link to the vendor's security-related job positions
   Multiple Appearances: Yes
   Published in: this document

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   Status: current
   Change controller: IESG

   Field Name: Policy
   Description: link to security policy page
   Multiple Appearances: Yes
   Published in: this document
   Status: current
   Change controller: IESG

   Field Name: Preferred-Languages
   Description: list of preferred languages for security reports
   Multiple Appearances: No
   Published in: this document
   Status: current
   Change controller: IESG

8.  Contributors

   The authors would like to acknowledge the help provided during the
   development of this document by Tom Hudson, Jobert Abma, Gerben
   Janssen van Doorn, Austin Heap, Stephane Bortzmeyer, Max Smith,
   Eduardo Vela, and Krzysztof Kotowicz.

   The authors would also like to acknowledge the feedback provided by
   multiple members of IETF's LAST CALL, SAAG, and SECDISPATCH lists.

   Yakov would like to also thank L.T.S. (for everything).

9.  References

9.1.  Normative References

   [RFC1945]  Berners-Lee, T., Fielding, R., and H. Frystyk, "Hypertext
              Transfer Protocol -- HTTP/1.0", RFC 1945,
              DOI 10.17487/RFC1945, May 1996,
              <https://www.rfc-editor.org/info/rfc1945>.

   [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Two: Media Types", RFC 2046,
              DOI 10.17487/RFC2046, November 1996,
              <https://www.rfc-editor.org/info/rfc2046>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

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   [RFC2142]  Crocker, D., "Mailbox Names for Common Services, Roles and
              Functions", RFC 2142, DOI 10.17487/RFC2142, May 1997,
              <https://www.rfc-editor.org/info/rfc2142>.

   [RFC2277]  Alvestrand, H., "IETF Policy on Character Sets and
              Languages", BCP 18, RFC 2277, DOI 10.17487/RFC2277,
              January 1998, <https://www.rfc-editor.org/info/rfc2277>.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818,
              DOI 10.17487/RFC2818, May 2000,
              <https://www.rfc-editor.org/info/rfc2818>.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
              2003, <https://www.rfc-editor.org/info/rfc3629>.

   [RFC3966]  Schulzrinne, H., "The tel URI for Telephone Numbers",
              RFC 3966, DOI 10.17487/RFC3966, December 2004,
              <https://www.rfc-editor.org/info/rfc3966>.

   [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,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC4880]  Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R.
              Thayer, "OpenPGP Message Format", RFC 4880,
              DOI 10.17487/RFC4880, November 2007,
              <https://www.rfc-editor.org/info/rfc4880>.

   [RFC5198]  Klensin, J. and M. Padlipsky, "Unicode Format for Network
              Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008,
              <https://www.rfc-editor.org/info/rfc5198>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [RFC5322]  Resnick, P., Ed., "Internet Message Format", RFC 5322,
              DOI 10.17487/RFC5322, October 2008,
              <https://www.rfc-editor.org/info/rfc5322>.

   [RFC5646]  Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
              Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
              September 2009, <https://www.rfc-editor.org/info/rfc5646>.

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   [RFC6068]  Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto'
              URI Scheme", RFC 6068, DOI 10.17487/RFC6068, October 2010,
              <https://www.rfc-editor.org/info/rfc6068>.

   [RFC6125]  Saint-Andre, P. and J. Hodges, "Representation and
              Verification of Domain-Based Application Service Identity
              within Internet Public Key Infrastructure Using X.509
              (PKIX) Certificates in the Context of Transport Layer
              Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
              2011, <https://www.rfc-editor.org/info/rfc6125>.

   [RFC6960]  Santesson, S., Myers, M., Ankney, R., Malpani, A.,
              Galperin, S., and C. Adams, "X.509 Internet Public Key
              Infrastructure Online Certificate Status Protocol - OCSP",
              RFC 6960, DOI 10.17487/RFC6960, June 2013,
              <https://www.rfc-editor.org/info/rfc6960>.

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <https://www.rfc-editor.org/info/rfc7230>.

   [RFC7231]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
              DOI 10.17487/RFC7231, June 2014,
              <https://www.rfc-editor.org/info/rfc7231>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8615]  Nottingham, M., "Well-Known Uniform Resource Identifiers
              (URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019,
              <https://www.rfc-editor.org/info/rfc8615>.

9.2.  Informative References

   [CERT.CVD] Software Engineering Institute, Carnegie Mellon
              University, "The CERT Guide to Coordinated Vulnerability
              Disclosure (CMU/SEI-2017-SR-022)", 2017.

   [ISO.29147.2018]
              International Organization for Standardization (ISO),
              "ISO/IEC 29147:2018, Information technology -- Security
              techniques -- Vulnerability disclosure", 2018.

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   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,
              RFC 793, DOI 10.17487/RFC0793, September 1981,
              <https://www.rfc-editor.org/info/rfc793>.

   [RFC2196]  Fraser, B., "Site Security Handbook", FYI 8, RFC 2196,
              DOI 10.17487/RFC2196, September 1997,
              <https://www.rfc-editor.org/info/rfc2196>.

   [RFC2350]  Brownlee, N. and E. Guttman, "Expectations for Computer
              Security Incident Response", BCP 21, RFC 2350,
              DOI 10.17487/RFC2350, June 1998,
              <https://www.rfc-editor.org/info/rfc2350>.

   [RFC2606]  Eastlake 3rd, D. and A. Panitz, "Reserved Top Level DNS
              Names", BCP 32, RFC 2606, DOI 10.17487/RFC2606, June 1999,
              <https://www.rfc-editor.org/info/rfc2606>.

   [RFC3013]  Killalea, T., "Recommended Internet Service Provider
              Security Services and Procedures", BCP 46, RFC 3013,
              DOI 10.17487/RFC3013, November 2000,
              <https://www.rfc-editor.org/info/rfc3013>.

   [RFC6890]  Cotton, M., Vegoda, L., Bonica, R., Ed., and B. Haberman,
              "Special-Purpose IP Address Registries", BCP 153,
              RFC 6890, DOI 10.17487/RFC6890, April 2013,
              <https://www.rfc-editor.org/info/rfc6890>.

   [RFC7485]  Zhou, L., Kong, N., Shen, S., Sheng, S., and A. Servin,
              "Inventory and Analysis of WHOIS Registration Objects",
              RFC 7485, DOI 10.17487/RFC7485, March 2015,
              <https://www.rfc-editor.org/info/rfc7485>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

Appendix A.  Note to Readers

      *Note to the RFC Editor:* Please remove this section prior to
      publication.

   Development of this draft takes place on Github at
   https://github.com/securitytxt/security-txt

Appendix B.  Document History

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      *Note to the RFC Editor:* Please remove this section prior to
      publication.

B.1.  Since draft-foudil-securitytxt-00

   *  Moved to use IETF's markdown tools for draft updates

   *  Added table of contents and a fuller list of references

   *  Moved file to .well-known URI and added IANA registration (#3)

   *  Added extensibility with an IANA registry for fields (#34)

   *  Added text explaining relationship to RFC 2142 / security@ email
      address (#25)

   *  Scope expanded to include internal hosts, domains, IP addresses
      and file systems

   *  Support for digital signatures added (#19)

   The full list of changes can be viewed via the IETF document tracker:
   https://tools.ietf.org/html/draft-foudil-securitytxt-01

B.2.  Since draft-foudil-securitytxt-01

   *  Added appendix with pointer to Github and document history

   *  Added external signature file to the well known URI registry (#59)

   *  Added policy field (#53)

   *  Added diagram explaining the location of the file on public vs.
      internal systems

   *  Added recommendation that external signature files should use
      HTTPS (#55)

   *  Added recommendation that organizations should monitor their
      security.txt files (#14)

   The full list of changes can be viewed via the IETF document tracker:
   https://tools.ietf.org/html/draft-foudil-securitytxt-02

B.3.  Since draft-foudil-securitytxt-02

   *  Use "mailto" and "tel" (#62)

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   *  Fix typo in the "Example" section (#64)

   *  Clarified that the root directory is a fallback option (#72)

   *  Defined content-type for the response (#68)

   *  Clarify the scope of the security.txt file (#69)

   *  Cleaning up text based on the NITS tools suggestions (#82)

   *  Added clarification for newline values

   *  Clarified the encryption field language, added examples of DNS-
      stored encryption keys (#28 and #94)

   *  Added "Hiring" field

B.4.  Since draft-foudil-securitytxt-03

   *  Added "Hiring" field to the registry section

   *  Added an encryption example using a PGP fingerprint (#107)

   *  Added reference to the mailing list (#111)

   *  Added a section referencing related work (#113)

   *  Fixes for idnits (#82)

   *  Changing some references to informative instead of normative

   *  Adding "Permission" field (#30)

   *  Fixing remaining ABNF issues (#83)

   *  Additional editorial changes and edits

B.5.  Since draft-foudil-securitytxt-04

   *  Addressing IETF feedback (#118)

   *  Case sensitivity clarification (#127)

   *  Syntax fixes (#133, #135 and #136)

   *  Removed permission field (#30)

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   *  Removed signature field and switched to inline signatures (#93 and
      #128)

   *  Adding canonical field (#100)

   *  Text and ABNF grammar improvements plus ABNF changes for comments
      (#123)

   *  Changed ".security.txt" to "security.txt" to be consistent

B.6.  Since draft-foudil-securitytxt-05

   *  Changing HTTPS to MUST (#55)

   *  Adding language recommending encryption for email reports (#134)

   *  Added language handling redirects (#143)

   *  Expanded security considerations section and fixed typos (#30,
      #73, #103, #112)

B.7.  Since draft-foudil-securitytxt-06

   *  Fixed ABNF grammar for non-chainable fields (#150)

   *  Clarified ABNF grammar (#152)

   *  Clarified redirect logic (#143)

   *  Clarified comments (#158)

   *  Updated references and template for well-known URI to RFC 8615

   *  Fixed nits from the IETF validator

B.8.  Since draft-foudil-securitytxt-07

   *  Addressing AD feedback (#165)

   *  Fix for ABNF grammar in lang-values (#164)

   *  Fixing idnits warnings

   *  Adding guidance for designated experts

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B.9.  Since draft-foudil-securitytxt-08

   *  Added language and example regarding URI encoding (#176)

   *  Add "Expires" field (#181)

   *  Changed language from "directive" to "field" (#182)

   *  Addressing last call feedback (#179, #180 and #183)

   *  Clarifying order of fields (#174)

   *  Revert comment/field association (#158)

B.10.  Since draft-foudil-securitytxt-09

   *  Adjust ABNF to allow blank lines between directives (#191)

   *  Make "Expires" field required (#190)

   *  Adding a warning about the well-known URI namespace (#188)

   *  Adding scope language around products/services (#185)

   *  Addressing last call feedback (#189)

   Full list of changes can be viewed via the IETF document tracker:
   https://tools.ietf.org/html/draft-foudil-securitytxt

Authors' Addresses

   Edwin Foudil

   Email: contact@edoverflow.com

   Yakov Shafranovich
   Nightwatch Cybersecurity

   Email: yakov+ietf@nightwatchcybersecurity.com

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