| Network Working Group | E. Foudil |
| Internet-Draft | |
| Intended status: Informational | Y. Shafranovich |
| Expires: August 13, 2018 | Nightwatch Cybersecurity |
| February 09, 2018 |
A Method for Web Security Policies
draft-foudil-securitytxt-03
When security risks in web services are discovered by independent security researchers who understand the severity of the risk, they often lack the channels to disclose them properly. As a result, security issues may be left unreported. security.txt defines a standard to help organizations describe the process for security researchers to disclose security vulnerabilities securely.
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Many security researchers encounter situations where they are unable to responsibly disclose security issues to companies because there is no course of action laid out. security.txt is designed to help assist in this process by making it easier for companies to designate the preferred steps for researchers to take when trying to reach out.
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 for security issues per domain, and does not provide a way for domain owners to publish information about their security disclosure policies.
In this document, we propose a richer, machine-parsable and more extensible way for companies to communicate information about their security disclosure policies, which is not limited to email and also allows for additional features such as encryption.
In this document, the key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” are to be interpreted as described in [RFC2119].
Development of this draft takes place on Github at: https://github.com/securitytxt/security-txt
security.txt is a text file that SHOULD be located under the /.well-known/ path (“/.well-known/security.txt”) [RFC5785] for web properties. If it is not possible to place the security.txt file in the /.well-known/ path or setup a redirect, web-based services MAY place the file in the top-level path as a fall back option. For web-based services, the instructions MUST be accessible via the Hypertext Transfer Protocol [RFC1945] as a resource of Internet Media Type “text/plain” with the default charset parameter set to “utf-8” per section 4.1.3 of [RFC2046]. For file systems and version control repositories a .security.txt file SHOULD be placed in the root directory.
This text file contains multiple directives with different values. The “directive” is the first part of a field all the way up to the colon (“Contact:”). Directives are case-insensitive. The “value” comes after the directive (“https://example.com/security”). A “field” always consists of a directive 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 you need a separate line for every field. One MUST NOT chain multiple values for a single directive. Everything MUST be in a separate field.
A security.txt file MUST only apply to the domain in the URI used to retrieve it, not to any of its subdomains or parent domains.
# 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. http://192.0.2.0/.well-known/security.txt # This security.txt file applies to IPv6 address of 2001:db8:8:4::2. http://[2001:db8:8:4::2]/.well-known/security.txt
Comments can be added using the # symbol:
# This is a comment.
You MAY use one or more comments as descriptive text immediately before the field. Parsers can then associate the comments with the respective field.
A separate line is required for every new value and field. You MUST NOT chain everything into a single field. Every line MUST end either with a carriage return and line feed characters (CRLF / %x0D %x0A) or just a line feed character (LF / %x0A).
Add an address that researchers MAY use for reporting security issues. The value can be an email address, a phone number and/or a contact page with more information. The “Contact:” directive MUST always be present in a security.txt file. URIs SHOULD be loaded over HTTPS. Security email addresses SHOULD use the conventions defined in section 4 of [RFC2142], but there is no requirement for this directive to be an email address.
The value MUST follow the general syntax described in [RFC3986]. This means that “mailto” and “tel” URI schemes MUST be used when specifying email addresses and telephone numbers.
The precedence is in listed order. The first field is the preferred method of contact. In the example below, the e-mail address is the preferred method of contact.
Contact: mailto:security@example.com Contact: tel:+1-201-555-0123 Contact: https://example.com/security-contact.html
This directive allows you to point to an encryption key that you want security researchers to use for encrypted communication. You MUST NOT directly add your key to the field, instead the value of this field MUST be a URI pointing to a location where the key can be retrieved from. If the key is being retrieved from a website, then the key MUST be loaded over HTTPS.
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 signature file referenced in Section 3.5.
Example of a PGP key available from a web server:
Encryption: https://example.com/pgp-key.txt
Example of a PGP key available from an OPENPGPKEY DNS record under “security@example.com” (as per [RFC7553] and [RFC7929]):
Encryption: dns:5d2d3ceb7abe552344276d47d36._openpgpkey.example.com?type=OPENPGPKEY
In order to ensure the authenticity of the security.txt file one SHOULD use the “Signature:” directive, which allows you to link to an external signature by specifying the full URI where the signature is located as per [RFC3986]. External signature files SHOULD be named “security.txt.sig” and also be placed under the /.well-known/ path. External signature files SHOULD be loaded over HTTPS.
When it comes to verifying the authenticity of the file, it is always the security researcher’s responsibility to make sure the key being specified is indeed one they trust.
Here is an example of an external signature file.
Signature: https://example.com/.well-known/security.txt.sig
With the Policy directive, you can link to where your security policy and/or disclosure policy is located. This can help security researchers understand what you are looking for and how to report security vulnerabilities.
Policy: https://example.com/security-policy.html
This directive allows you to link to a page where security researchers are recognized for their reports. The page SHOULD list individuals or companies that disclosed security vulnerabilities and worked with you to remediate the issue.
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
The “Hiring” directive is for linking to the vendor’s security-related job positions.
Hiring: https://example.com/jobs.html
# Our security address Contact: mailto:security@example.com # Our PGP 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 # Verify this security.txt file Signature: https://example.com/.well-known/security.txt.sig
External
+----------------------------------------------------------------+
| Default |
| +-----------------------------+ +-----------------+ |
| | | Redirect | | |
| | /.well-known/security.txt <----------+ /security.txt | |
| | | | | |
| +-----------------------------+ +-----------------+ |
| |
+----------------------------------------------------------------+
Internal
+------------------------+
| |
| +------------------+ |
| | | |
| | /.security.txt | |
| | | |
| +------------------+ |
| |
+------------------------+
Web-based services SHOULD place the security.txt file under the /.well-known/ path; e.g. https://example.com/.well-known/security.txt. A security.txt file located under the top-level path SHOULD either redirect to the security.txt file under the /.well-known/ path or be used as a fall back.
File systems SHOULD place the security.txt file under the root directory; e.g., /.security.txt, C:.security.txt.
user:/$ l .security.txt example-directory-1/ example-directory-2/ example-directory-3/ example-file
A .security.txt file SHOULD be placed in the root directory of an internal host to trigger incident response.
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 headers 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.
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 = *line (contact-field eol) *line
line = *1(field / comment) eol
eol = *WSP \[CR\] LF
field = contact-field /
encryption-field /
acknowledgments-field /
ext-field
fs = ":"
comment = "#" *(WSP / VCHAR / %xA0-E007F)
contact-field = "Contact" fs SP (email / uri / phone)
email = <Email address as per {{RFC5322}}>
phone = "+" *1(DIGIT / "-" / "(" / ")" / SP)
uri = <URI as per {{RFC3986}}>
encryption-field = "Encryption" fs SP uri
signature-field = "Signature" fs SP uri
policy-field = "Policy" fs SP uri
acknowledgments-field = "Acknowledgments" fs SP uri
hiring-field = "Hiring" fs SP uri
ext-field = field-name fs SP unstructured
field-name = <as per section 3.6.8 of {{RFC5322}}>
unstructured = <as per section 3.2.5 of {{RFC5322}}>
“ext-field” refers to extension fields, which are discussed in Section 4.4
Organizations creating security.txt files will need to consider several security-related issues. These include exposure to sensitive information and attacks where limited access to a server could grant the ability to modify the contents of the security.txt file or affect how it is served. Organizations SHOULD also monitor their security.txt files regularly to detect tampering.
To ensure the authenticity of the security.txt file, organizations SHOULD sign the file and include the signature using the “Signature:” directive.
As stated in Section 3.4 and Section 3.5, both encryption keys and external signature files SHOULD be loaded over HTTPS.
Websites MUST reserve the security.txt namespace to ensure no third-party can create a page with the “security.txt” name.
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].
The “Well-Known URIs” registry should be updated with the following additional values (using the template from [RFC5785]):
URI suffix: security.txt
URI suffix: security.txt.sig
Change controller: IETF
Specification document(s): this document
IANA is requested to create the “security.txt Header Fields” registry in accordance with [RFC8126]. This registry will contain header fields for use in security.txt files, defined by this specification.
New registrations or updates MUST be published in accordance with the “Specification Required” guidelines as described in section 4.6 of [RFC8126]. Any new field thus registered is considered optional by this specification unless a new version of this specification is published.
New registrations and updates MUST contain the following information:
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: Acknowledgment Description: link to page where security researchers are recognized Multiple Appearances: Yes Published in: this document Status: current Field Name: Contact Description: contact information to use for reporting security issues Multiple Appearances: Yes Published in: this document Status: current Field Name: Encryption Description: link to a key to be used for encrypted communication Multiple Appearances: Yes Published in: this document Status: current Field Name: Signature Description: signature used to verify the authenticity of the file Multiple Appearances: No Published in: this document Status: current Field Name: Policy Description: link to security policy page Multiple Appearances: No Published in: this document Status: current
The editors would like to acknowledge the help provided during the development of this document by Tom Hudson, Joel Margolis, Jobert Abma, Gerben Janssen van Doorn, Austin Heap, Justin Calmus, and Casey Ellis.
| [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. |
Development of this draft takes place on Github at https://github.com/securitytxt/security-txt
The full list of changes can be viewed via the IETF document tracker: https://tools.ietf.org/html/draft-foudil-securitytxt-01
The full list of changes can be viewed via the IETF document tracker: https://tools.ietf.org/html/draft-foudil-securitytxt-02
Full list of changes can be viewed via the IETF document tracker: https://tools.ietf.org/html/draft-foudil-securitytxt-03