Challenges and Changes in the Internet Threat Model
draft-arkko-farrell-arch-model-t-02

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Network Working Group                                           J. Arkko
Internet-Draft                                                  Ericsson
Intended status: Informational                                S. Farrell
Expires: 9 August 2020                            Trinity College Dublin
                                                         6 February 2020

          Challenges and Changes in the Internet Threat Model
                  draft-arkko-farrell-arch-model-t-02

Abstract

   Communications security has been at the center of many security
   improvements in the Internet.  The goal has been to ensure that
   communications are protected against outside observers and attackers.

   This memo suggests that the existing RFC 3552 threat model, while
   important and still valid, is no longer alone sufficient to cater for
   the pressing security and privacy issues seen on the Internet today.
   For instance, it is often also necessary to protect against endpoints
   that are compromised, malicious, or whose interests simply do not
   align with the interests of users.  While such protection is
   difficult, there are some measures that can be taken and we argue
   that investigation of these issues is warranted.

   It is particularly important to ensure that as we continue to develop
   Internet technology, non-communications security related threats, and
   privacy issues, are properly understood.

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
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   This Internet-Draft will expire on 9 August 2020.

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Table of Contents

   1.  Introduction
   2.  Observations
       2.1.  Communications Security Improvements
       2.2.  Beyond Communications Security
       2.3.  Examples
             2.3.1.  Deliberate adversarial behaviour in
                     applications
             2.3.2.  Inadvertent adversarial behaviours
   3.  Analysis
       3.1.  The Role of End-to-end
       3.2.  Trusted networks
             3.2.1.  Even closed networks can have compromised
                     nodes
       3.3.  Balancing Threats
   4.  Areas requiring more study
   5.  Guidelines
   6.  Potential changes in BCP 72/RFC 3552
   7.  Potential Changes in BCP 188/RFC 7258
   8.  Conclusions
   9.  Informative References
   Appendix A.  Acknowledgements
   Authors' Addresses

1.  Introduction

   Communications security has been at the center of many security
   improvements in the Internet.  The goal has been to ensure that
   communications are protected against outside observers and attackers.
   At the IETF, this approach has been formalized in BCP 72 [RFC3552],
   which defined the Internet threat model in 2003.

   The purpose of a threat model is to outline what threats exist in
   order to assist the protocol designer.  But RFC 3552 also ruled some
   threats to be in scope and of primary interest, and some threats out
   of scope [RFC3552]:

      The Internet environment has a fairly well understood threat
      model.  In general, we assume that the end-systems engaging in a
      protocol exchange have not themselves been compromised.
      Protecting against an attack when one of the end-systems has been
      compromised is extraordinarily difficult.  It is, however,
      possible to design protocols which minimize the extent of the
      damage done under these circumstances.

      By contrast, we assume that the attacker has nearly complete
      control of the communications channel over which the end-systems
      communicate.  This means that the attacker can read any PDU
      (Protocol Data Unit) on the network and undetectably remove,
      change, or inject forged packets onto the wire.

   However, the communications-security -only threat model is becoming