Network Working Group E. Foudil
Internet-Draft
Intended status: Informational Y. Shafranovich
Expires: 25 November 2021 Nightwatch Cybersecurity
24 May 2021
A File Format to Aid in Security Vulnerability Disclosure
draft-foudil-securitytxt-12
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 machine-parsable
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 25 November 2021.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
Foudil & Shafranovich Expires 25 November 2021 [Page 1]
Internet-Draft security.txt May 2021
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 . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Comments . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Line Separator . . . . . . . . . . . . . . . . . . . . . 6
3.3. Digital signature . . . . . . . . . . . . . . . . . . . . 6
3.4. Extensibility . . . . . . . . . . . . . . . . . . . . . . 6
3.5. Field Definitions . . . . . . . . . . . . . . . . . . . . 6
3.5.1. Acknowledgments . . . . . . . . . . . . . . . . . . . 6
3.5.2. Canonical . . . . . . . . . . . . . . . . . . . . . . 7
3.5.3. Contact . . . . . . . . . . . . . . . . . . . . . . . 7
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. Scope of the File . . . . . . . . . . . . . . . . . . . . 11
5. File Format Description and ABNF Grammar . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
6.1. Compromised Files and Incident Response . . . . . . . . . 14
6.2. Redirects . . . . . . . . . . . . . . . . . . . . . . . . 14
6.3. Incorrect or Stale Information . . . . . . . . . . . . . 14
6.4. Intentionally Malformed Files, Resources and Reports . . 15
6.5. No Implied Permission for Testing . . . . . . . . . . . . 15
6.6. Multi-user Environments . . . . . . . . . . . . . . . . . 15
6.7. Protecting Data in Transit . . . . . . . . . . . . . . . 16
6.8. Spam and Spurious Reports . . . . . . . . . . . . . . . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
7.1. Well-Known URIs registry . . . . . . . . . . . . . . . . 17
7.2. Registry for security.txt Fields . . . . . . . . . . . . 17
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
Foudil & Shafranovich Expires 25 November 2021 [Page 2]
Internet-Draft security.txt May 2021
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
B.11. Since draft-foudil-securitytxt-10 . . . . . . . . . . . . 26
B.12. Since draft-foudil-securitytxt-11 . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
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 issues. That convention provides only a single,
email-based channel of communication 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
tackle the issue of how security researchers can locate contact
information and vulnerability disclosure practices for organizations
in order to report vulnerabilities.
Foudil & Shafranovich Expires 25 November 2021 [Page 3]
Internet-Draft security.txt May 2021
In this document, we define a richer, machine-parsable 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.
The term "researcher" corresponds to the terms "finder" and
"reporter" in [ISO.29147.2018] and [CERT.CVD]. The term
"organization" corresponds to the term "vendor" in [ISO.29147.2018]
and [CERT.CVD].
The term "implementors" includes all parties involved in the
vulnerability disclosure process.
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
Foudil & Shafranovich Expires 25 November 2021 [Page 4]
Internet-Draft security.txt May 2021
3. The Specification
This document defines a text file to be placed in a known location
that provides information about vulnerability disclosure practices of
a particular organization. The format of this file is machine-
parsable and MUST follow the ABNF grammar defined in Section 5. This
file is intended to help security researchers when disclosing
security vulnerabilities.
By convention, the file is named "security.txt". Location and scope
are described in Section 4.
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 (for example: "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 (for example:
"mailto:[email protected]") 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 (for example:
"Contact: mailto:[email protected]"). A "security.txt" file can
have an unlimited number of fields. 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, a
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. Comments
Any line beginning with the "#" (%x23) 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.
Foudil & Shafranovich Expires 25 November 2021 [Page 5]
Internet-Draft security.txt May 2021
3.2. 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).
3.3. 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 organizations use the "Canonical" field (as per Section 3.5.2),
thus allowing the digital signature to authenticate the location of
the file.
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.
3.4. 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, researchers 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]).
3.5. Field Definitions
Unless otherwise stated, all fields MUST be considered optional.
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
security researchers 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 URI, then it MUST begin with "https://"
(as per section 2.7.2 of [RFC7230]).
Foudil & Shafranovich Expires 25 November 2021 [Page 6]
Internet-Draft security.txt May 2021
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 URI, then it MUST begin with "https://" (as per
section 2.7.2 of [RFC7230]).
While this field indicates that a "security.txt" retrieved from a
given URI is intended to apply to that URI, it MUST NOT be
interpreted to apply to all canonical URIs listed within the file.
Researchers SHOULD use an additional trust mechanism such as a
digital signature (as per Section 3.3) to make the determination that
a particular canonical URI is applicable.
If this field appears within a "security.txt" file, and the URI used
to retrieve that file is not listed within any canonical fields, then
the contents of the file SHOULD NOT be trusted.
Canonical: https://www.example.com/.well-known/security.txt
Canonical: https://someserver.example.com/.well-known/security.txt
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 URI, 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 section 3 of
[RFC3986]. This means that "mailto" and "tel" URI schemes must be
used when specifying email addresses and telephone numbers, as
Foudil & Shafranovich Expires 25 November 2021 [Page 7]
Internet-Draft security.txt May 2021
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 occurrence is
the preferred method of contact. In the example below, the first
email address ("[email protected]") is the preferred method of
contact.
Contact: mailto:[email protected]
Contact: mailto:security%2Buri%[email protected]
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 URI, 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 3.3.
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
Example of an OpenPGP key being referenced by its fingerprint:
Encryption: openpgp4fpr:5f2de5521c63a801ab59ccb603d49de44b29100f
Foudil & Shafranovich Expires 25 November 2021 [Page 8]
Internet-Draft security.txt May 2021
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 is formatted according
to the Internet profile of [ISO.8601] as defined in [RFC3339]. 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: 2021-12-31T18:37:07z
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 URI, 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 URI, 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]).
The order in which they appear is not an indication of priority; the
listed languages are intended to have equal priority.
This field MUST NOT appear more than once.
Foudil & Shafranovich Expires 25 November 2021 [Page 9]
Internet-Draft security.txt May 2021
Example (English, Spanish and French):
Preferred-Languages: en, es, fr
3.6. Example of an unsigned "security.txt" file
# Our security address
Contact: mailto:[email protected]
# 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
Expires: 2021-12-31T18:37:07z
3.7. Example of a signed "security.txt" file
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
# Canonical URI
Canonical: https://example.com/.well-known/security.txt
# Our security address
Contact: mailto:[email protected]
# 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
Expires: 2021-12-31T18:37:07z
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.2
[signature]
-----END PGP SIGNATURE-----
Foudil & Shafranovich Expires 25 November 2021 [Page 10]
Internet-Draft security.txt May 2021
4. Location of the security.txt file
For web-based services, organizations MUST place the "security.txt"
file under the "/.well-known/" path; e.g. https://example.com/.well-
known/security.txt as per [RFC8615] of a domain name or IP address.
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.
The file MUST be accessed via HTTP 1.0 or a higher version and the
file access MUST use "https" scheme (as per 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]).
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 analysis (as per Section 6.2)
to make sure these redirects are not malicious or pointing to
resources controlled by an attacker.
4.1. Scope of the File
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 MAY also apply to products and
services provided by the organization publishing the file.
As per Section 1.1, this specification is intended for vulnerability
response. If implementors want to use this for incident response,
they should be aware of additional security considerations discussed
in Section 6.1.
Organizations 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:
Foudil & Shafranovich Expires 25 November 2021 [Page 11]
Internet-Draft security.txt May 2021
# 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
5. File Format Description and ABNF Grammar
The file format of the "security.txt" file MUST be plain text (MIME
type "text/plain") as defined in section 4.1.3 of [RFC2046] and MUST
be encoded using UTF-8 [RFC3629] in Net-Unicode form [RFC5198].
The format of this file MUST follow the ABNF definition below (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) ; one or more required
*line (expires-field eol) ; exactly one required
*line [lang-field eol] *line ; exactly one optional
; order of fields within the file is not important
; except that if contact-field appears more
; than once the order of those indicates
; priority (see Section 3.5.3)
line = [ (field / comment) ] eol
eol = *WSP [CR] LF
field = ; optional fields
ack-field /
can-field /
contact-field / ; optional repeated instances
encryption-field /
hiring-field /
policy-field /
Foudil & Shafranovich Expires 25 November 2021 [Page 12]
Internet-Draft security.txt May 2021
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
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 5.6 of [RFC3339] >
lang-tag = < Language-Tag from section 2.1 of [RFC5646] >
lang-values = lang-tag *(*WSP "," *WSP lang-tag)
uri = < URI as per section 3 of [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 3.4
6. Security Considerations
Because of the use of URIs and well-known resources, security
considerations of [RFC3986] and [RFC8615] apply here, in addition to
the considerations outlined below.
Foudil & Shafranovich Expires 25 November 2021 [Page 13]
Internet-Draft security.txt May 2021
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 3.3), and
regularly monitor the file and the referenced resources to detect
tampering.
Security researchers should validate 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.
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. Researchers should use additional methods to verify such
data including out of band verification of the PGP signature, DNSSEC-
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.
Foudil & Shafranovich Expires 25 November 2021 [Page 14]
Internet-Draft security.txt May 2021
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. Researchers
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.
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
the domain or IP address where it is published, or products and
services provided by the organization publishing the file. 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, researchers 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 3.4).
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.
Foudil & Shafranovich Expires 25 November 2021 [Page 15]
Internet-Draft security.txt May 2021
6.7. Protecting Data in Transit
To protect a "security.txt" file from being tampered with in transit,
implementors MUST use HTTPS (as per section 2.7.2 of [RFC7230]) when
serving the file itself and for retrieval of any web URIs referenced
in it (except when otherwise noted in this specification). As part
of the TLS handshake, researchers 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.
In cases where the "security.txt" file cannot be served via HTTPS
(such as localhost) or is being served with an invalid certificate,
additional human validation 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 3.3). 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 analysis. Attackers can also use this
file as a way to spam unrelated third parties by listing their
resources and/or contact information.
Foudil & Shafranovich Expires 25 November 2021 [Page 16]
Internet-Draft security.txt May 2021
Organizations need to weigh the advantages of publishing this file
versus the possible disadvantages and increased resources required to
analyze 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
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]).
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
Foudil & Shafranovich Expires 25 November 2021 [Page 17]
Internet-Draft security.txt May 2021
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 has been in use, but new usage is
discouraged
* 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: IETF
Field Name: Canonical
Description: canonical URI for this file
Multiple Appearances: Yes
Published in: this document
Status: current
Change controller: IETF
Field Name: Contact
Description: contact information to use for reporting vulnerabilities
Multiple Appearances: Yes
Published in: this document
Status: current
Change controller: IETF
Field Name: Expires
Description: date and time after which this file is considered stale
Multiple Appearances: No
Published in: this document
Foudil & Shafranovich Expires 25 November 2021 [Page 18]
Internet-Draft security.txt May 2021
Status: current
Change controller: IETF
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: IETF
Field Name: Hiring
Description: link to the vendor's security-related job positions
Multiple Appearances: Yes
Published in: this document
Status: current
Change controller: IETF
Field Name: Policy
Description: link to security policy page
Multiple Appearances: Yes
Published in: this document
Status: current
Change controller: IETF
Field Name: Preferred-Languages
Description: list of preferred languages for security reports
Multiple Appearances: No
Published in: this document
Status: current
Change controller: IETF
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
Foudil & Shafranovich Expires 25 November 2021 [Page 19]
Internet-Draft security.txt May 2021
[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>.
[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>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[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>.
Foudil & Shafranovich Expires 25 November 2021 [Page 20]
Internet-Draft security.txt May 2021
[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>.
[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.
Foudil & Shafranovich Expires 25 November 2021 [Page 21]
Internet-Draft security.txt May 2021
[ISO.29147.2018]
International Organization for Standardization (ISO),
"ISO/IEC 29147:2018, Information technology - Security
techniques - Vulnerability disclosure", 2018.
[ISO.8601] International Organization for Standardization (ISO),
"ISO/IEC 8601, Date and time - Representations for
information interchange - Parts 1 and 2", 2019.
[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>.
[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>.
[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
Foudil & Shafranovich Expires 25 November 2021 [Page 22]
Internet-Draft security.txt May 2021
*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)
Foudil & Shafranovich Expires 25 November 2021 [Page 23]
Internet-Draft security.txt May 2021
* 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)
Foudil & Shafranovich Expires 25 November 2021 [Page 24]
Internet-Draft security.txt May 2021
* 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
Foudil & Shafranovich Expires 25 November 2021 [Page 25]
Internet-Draft security.txt May 2021
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)
B.11. Since draft-foudil-securitytxt-10
* Changes addressing IESG feedback
* Removed language regarding file systems (#201)
* Adding language to explain alignment with the CERT CVD guide
(#202)
B.12. Since draft-foudil-securitytxt-11
* Changed date format from RFC 5322 to RFC 3339 / ISO 8601 (#208)
* Added clarification in "canonical" field regarding the URI used to
retrieve the file
* Added language about machine-parsability
* Added quotes around "security.txt" for consistency
Full list of changes can be viewed via the IETF document tracker:
https://tools.ietf.org/html/draft-foudil-securitytxt
Foudil & Shafranovich Expires 25 November 2021 [Page 26]
Internet-Draft security.txt May 2021
Authors' Addresses
Edwin Foudil
Email: [email protected]
Yakov Shafranovich
Nightwatch Cybersecurity
Email: [email protected]
Foudil & Shafranovich Expires 25 November 2021 [Page 27]
