Attack and Threat Model for Certificate Transparency
draft-ietf-trans-threat-analysis-14

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Public Notary Transparency                                       S. Kent
Internet-Draft                                               Independent
Intended status: Informational                              May 29, 2018
Expires: November 30, 2018

          Attack and Threat Model for Certificate Transparency
                  draft-ietf-trans-threat-analysis-14

Abstract

   This document describes an attack model and discusses threats for the
   Web PKI context for which security mechanisms to detect mis-issuance
   of web site certificates are being developed.  The model provides an
   analysis of detection and remediation mechanisms for both syntactic
   and semantic mis-issuance.  The model introduces an outline of
   attacks to organize the discussion.  The model also describes the
   roles played by the elements of the Certificate Transparency (CT)
   system, to establish a context for the model.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on November 30, 2018.

Copyright Notice

   Copyright (c) 2018 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
   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

Kent                    Expires November 30, 2018               [Page 1]
Internet-Draft  Attack Model for Certificate Mis-issuance       May 2018

   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.  Conventions used in this document . . . . . . . . . . . .   8
   2.  Threats . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   3.  Semantic mis-issuance . . . . . . . . . . . . . . . . . . . .  10
     3.1.  Non-malicious Web PKI CA context  . . . . . . . . . . . .  10
       3.1.1.  Certificate logged  . . . . . . . . . . . . . . . . .  10
         3.1.1.1.  Benign log  . . . . . . . . . . . . . . . . . . .  10
         3.1.1.2.  Misbehaving log . . . . . . . . . . . . . . . . .  11
         3.1.1.3.  Misbehaving third party Monitor . . . . . . . . .  12
       3.1.2.  Certificate not logged  . . . . . . . . . . . . . . .  12
         3.1.2.1.  CT-enabled browser  . . . . . . . . . . . . . . .  12
     3.2.  Malicious Web PKI CA context  . . . . . . . . . . . . . .  13
       3.2.1.  Certificate logged  . . . . . . . . . . . . . . . . .  13
         3.2.1.1.  Benign log  . . . . . . . . . . . . . . . . . . .  13
         3.2.1.2.  Misbehaving log . . . . . . . . . . . . . . . . .  14
         3.2.1.3.  Misbehaving third party Monitor . . . . . . . . .  14
       3.2.2.  Certificate not logged  . . . . . . . . . . . . . . .  14
         3.2.2.1.  CT-aware browser  . . . . . . . . . . . . . . . .  15
     3.3.  Undetected Compromise of CAs or Logs  . . . . . . . . . .  15
       3.3.1.  Compromised CA, Benign Log  . . . . . . . . . . . . .  16
       3.3.2.  Benign CA, Compromised Log  . . . . . . . . . . . . .  17
       3.3.3.  Compromised CA, Compromised Log . . . . . . . . . . .  18
     3.4.  Attacks Based on Exploiting Multiple Certificate Chains .  19
     3.5.  Attacks Related to Distribution of Revocation Status  . .  20
   4.  Syntactic mis-issuance  . . . . . . . . . . . . . . . . . . .  21
     4.1.  Non-malicious Web PKI CA context  . . . . . . . . . . . .  22
       4.1.1.  Certificate logged  . . . . . . . . . . . . . . . . .  22
         4.1.1.1.  Benign log  . . . . . . . . . . . . . . . . . . .  22
         4.1.1.2.  Misbehaving log or third party Monitor  . . . . .  23
       4.1.2.  Certificate not logged  . . . . . . . . . . . . . . .  23
         4.1.2.1.  Self-monitoring Subject . . . . . . . . . . . . .  23
       4.1.3.  Situations Independent of Certificate Logging . . . .  24
         4.1.3.1.  Self-monitoring Subject and Benign third party