Skip to main content

Explicit Forged Answer Signal
draft-pan-dnsop-explicit-forged-answer-signal-01

Document Type Active Internet-Draft (individual)
Authors Pan Lanlan , Yu Fu , Cuicui Wang
Last updated 2024-08-20
RFC stream (None)
Intended RFC status (None)
Formats
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date (None)
Responsible AD (None)
Send notices to (None)
draft-pan-dnsop-explicit-forged-answer-signal-01
dnsop                                                             L. Pan
Internet-Draft                                                          
Intended status: Best Current Practice                             Y. Fu
Expires: 21 February 2025                                        C. Wang
                                                            China Unicom
                                                          20 August 2024

                     Explicit Forged Answer Signal
            draft-pan-dnsop-explicit-forged-answer-signal-01

Abstract

   This document describes about the forged answer provided by recursive
   resolver.

   Client could protect user on security and privacy more efficiently if
   recursive resolver gives explict signal in the forged answer.

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 21 February 2025.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Pan, et al.             Expires 21 February 2025                [Page 1]
Internet-Draft                    EFAS                       August 2024

   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 Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  HTTP Cookies Leakage  . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Explicit Forged Answer Signal . . . . . . . . . . . . . . . .   3
     3.1.  Recursive Resolver  . . . . . . . . . . . . . . . . . . .   3
     3.2.  Client  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Background

   Recursive resolver may make a forged answer for a dns query in some
   specific scenarios, such as NXDOMAIN, phishing, fraud, malware,
   ransomware, botnet DDoS attack, and legal requirement, etc.  See also
   [NXRedierct] [ISPRedirect] [DNSFirewall] [LegalRedirect].

   The RCODE of faked answer is NOERROR, which make client hard to
   distinguish it with honest answer, if client doesn't make iterative
   dns query by itself, or make DNSSEC validation.

   Faked answer can avoid user to visit malicious website, however, it
   may also increase the security and privacy risk.

1.1.  HTTP Cookies Leakage

   The HTTP cookies risk has been well discussed in [NXDamageControl]
   and [NXDNSLies].  Furthermore, the risk is not only occured on
   NXDOMAIN scenario, but also on other faked answer scenarios.

   Imagine that user visits "abc.example.com" in browser.

   Recursive resolver return a faked answer to browser.

Pan, et al.             Expires 21 February 2025                [Page 2]
Internet-Draft                    EFAS                       August 2024

   Browser will visit the faked server, and leak the HTTP cookies in
   "example.com" of the user to it.

   With the leaked HTTP cookies, the faked server may pretend as the
   user to visit "abc.example.com", result in user's security issue and
   privacy leakage.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

   Basic terms used in this specification are defined in the documents
   [RFC1034], [RFC1035], [RFC8499].

   *  Authoritative Server: Described in [RFC8499].

   *  Recursive Resolver: Described in [RFC8499].

3.  Explicit Forged Answer Signal

   To avoid the HTTP cookies leakage, the recursive resolver is
   responsible for giving explict forged answer signal to client, and
   client could make its own reaction when it received an explict forged
   answer signal from recursive resolver.

3.1.  Recursive Resolver

   Recursive resolver could give the explict forged answer signal by
   including an additional Extended DNS Errors (EDE) information in DNS
   response, which is defined in [RFC8914].

   Alternatively, recursive resolver could include an TXT RR in DNS
   answer section, such as:

   abc.example.com  300 IN  A  1.2.3.4
   abc.example.com  300 IN  TXT  "faked=malware"

3.2.  Client

   Client could implement its own policy to deal with the forged answer:

   *  Use DNSSEC: Client could make DNSSEC query by itself.  If the
      domain has deployed DNSSEC, the client could validate the honest
      answer from authoritative server.

Pan, et al.             Expires 21 February 2025                [Page 3]
Internet-Draft                    EFAS                       August 2024

   *  Change Recursive Resolver: Client could change to another
      recursive resolver which is not lying.

   *  Stop Visit: Client could stop to visit on the website, since it
      knows that the answer is faked.

   *  Limited Visit: Client could make limited visit on the website,
      prevent HTTP cookies from being send to the faked server.  For
      example, browser should not send user's HTTP cookies to the faked
      server, if it gets an explict faked answer signal in the DoH
      response [RFC8484].

4.  Security Considerations

   Faked answer is unauthenticated by authoritative server, just offered
   by recursive resolver on some specific scenarios.  With the DNSSEC
   deployed on second level domain, client would not trust any faked
   answer if it makes all RRSIG validation by itself.  Ideally,
   recursive resolver should be honest to client, give the explicit
   faked answer signal in DNS response.  Explict faked answer signal
   could help browser to mitigate the http cookies leaked to faked
   server, protect user security and privacy in conditional limited
   environment.

5.  Acknowledgements

   Thanks to all in the DNSOP mailing list.

6.  References

6.1.  Normative References

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

   [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>.

   [RFC8484]  Hoffman, P. and P. McManus, "DNS Queries over HTTPS
              (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
              <https://www.rfc-editor.org/info/rfc8484>.

Pan, et al.             Expires 21 February 2025                [Page 4]
Internet-Draft                    EFAS                       August 2024

   [RFC8499]  Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
              Terminology", RFC 8499, DOI 10.17487/RFC8499, January
              2019, <https://www.rfc-editor.org/info/rfc8499>.

   [RFC8914]  Kumari, W., Hunt, E., Arends, R., Hardaker, W., and D.
              Lawrence, "Extended DNS Errors", RFC 8914,
              DOI 10.17487/RFC8914, October 2020,
              <https://www.rfc-editor.org/info/rfc8914>.

6.2.  Informative References

   [DNSFirewall]
              ISC, "Response Policy Zones (RPZ)", n.d.,
              <https://www.isc.org/rpz/>.

   [ISPRedirect]
              Weber, J. L. R., "DNS Redirect Use by Service Providers",
              n.d., <https://datatracker.ietf.org/doc/draft-livingood-
              dns-redirect/>.

   [LegalRedirect]
              York, D., "Oups! French Government Mistakenly Blocks
              Telegram Access for Millions", n.d.,
              <https://pulse.internetsociety.org/blog/oups-french-
              government-mistakenly-blocks-telegram-access-for-
              millions>.

   [NXDamageControl]
              Vixie, P., "What DNS Is Not", n.d.,
              <https://queue.acm.org/detail.cfm?id=1647302>.

   [NXDNSLies]
              Huston, G., "NXDOMAIN?", n.d.,
              <https://www.potaroo.net/ispcol/2009-12/nxdomain.pdf>.

   [NXRedierct]
              ISC, "NXDOMAIN Redirection Using DLZ in BIND 9.10 and
              later", n.d., <https://kb.isc.org/docs/aa-01150>.

Authors' Addresses

   Lanlan Pan
   Guangdong
   China
   Email: abbypan@gmail.com

Pan, et al.             Expires 21 February 2025                [Page 5]
Internet-Draft                    EFAS                       August 2024

   Yu Fu
   China Unicom
   Beijing
   China
   Email: fuy186@chinaunicom.cn

   Cuicui Wang
   China Unicom
   Beijing
   China
   Email: wangcc107@chinaunicom.cn

Pan, et al.             Expires 21 February 2025                [Page 6]