MUD (D)TLS profiles for IoT devices
draft-reddy-opsawg-mud-tls-04

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Last updated 2020-08-05
Replaces draft-reddy-opswg-mud-tls
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OPSWG WG                                                        T. Reddy
Internet-Draft                                                    McAfee
Intended status: Standards Track                                 D. Wing
Expires: February 6, 2021                                         Citrix
                                                             B. Anderson
                                                                   Cisco
                                                          August 5, 2020

                  MUD (D)TLS profiles for IoT devices
                     draft-reddy-opsawg-mud-tls-04

Abstract

   This memo extends Manufacturer Usage Description (MUD) to incorporate
   (D)TLS profile parameters.  This allows a network element to identify
   unexpected (D)TLS usage, which can indicate the presence of
   unauthorized software or malware on an endpoint.

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
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   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 February 6, 2021.

Copyright Notice

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

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Overview of MUD (D)TLS profiles for IoT devices . . . . . . .   5
   4.  (D)TLS 1.3 handshake  . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Full (D)TLS 1.3 handshake inspection  . . . . . . . . . .   6
     4.2.  Encrypted SNI . . . . . . . . . . . . . . . . . . . . . .   6
   5.  (D)TLS profile YANG module  . . . . . . . . . . . . . . . . .   7
     5.1.  Tree Structure  . . . . . . . . . . . . . . . . . . . . .   9
     5.2.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  10
   6.  MUD File Example  . . . . . . . . . . . . . . . . . . . . . .  15
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  16
   8.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  16
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  17
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  17
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  17
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  17
     11.2.  Informative References . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20

1.  Introduction

   Encryption is necessary to protect the privacy of end users using IoT
   devices.  In a network setting, TLS [RFC8446] and DTLS
   [I-D.ietf-tls-dtls13] are the dominant protocols providing encryption
   for IoT device traffic.  Unfortunately, in conjunction with IoT
   applications' rise of encryption, malware is also using encryption
   which thwarts network-based analysis such as deep packet inspection
   (DPI).  Other mechanisms are needed to notice malware is running on
   the IoT device.

   Malware frequently uses its own libraries for its activities, and
   those libraries are re-used much like any other software engineering
   project.  Research [malware] indicates there are observable
   differences in how malware uses encryption compared with how non-
   malware uses encryption.  There are several interesting findings
   specific to DTLS and TLS which were found common to malware:

   o  Older and weaker cryptographic parameters (e.g.,
      TLS_RSA_WITH_RC4_128_SHA).

   o  TLS SNI and server certificates are composed of subjects with
      characteristics of a domain generation algorithm (DGA) (e.g.,
      www.33mhwt2j.net).

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