Attack and Threat Model for Certificate Transparency
draft-ietf-trans-threat-analysis-11
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Active Internet-Draft (trans WG)
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2017-04-17
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IETF
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(None)
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plain text
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bibtex
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WG state
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In WG Last Call
(wg milestone:
Jul 2016 - Threat analysis to w...
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Revised I-D Needed - Issue raised by WGLC
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Document shepherd |
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Melinda Shore
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I-D Exists
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Unknown
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Send notices to |
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"Melinda Shore" <melinda.shore@gmail.com>
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Public Notary Transparency S. Kent
Internet-Draft BBN Technologies
Intended status: Informational April 17, 2017
Expires: October 17, 2017
Attack and Threat Model for Certificate Transparency
draft-ietf-trans-threat-analysis-11
Abstract
This document describes an attack model and discusses threats for the
Web PKI context in 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
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 http://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 April 21, 2017.
Copyright Notice
Copyright (c) 2016 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
Provisions Relating to IETF Documents
(http://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 April 21, 2017 [Page 1]
Internet-Draft Attack Model for Certificate Mis-issuance April 2017
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 . . . . . . . . . . . . 7
2. Threats . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3. Semantic mis-issuance . . . . . . . . . . . . . . . . . . . . 9
3.1. Non-malicious Web PKI CA context . . . . . . . . . . . . 9
3.1.1. Certificate logged . . . . . . . . . . . . . . . . . 9
3.1.2. Certificate not logged . . . . . . . . . . . . . . . 11
3.2. Malicious Web PKI CA context . . . . . . . . . . . . . . 12
3.2.1. Certificate logged . . . . . . . . . . . . . . . . . 12
3.2.2. Certificate not logged . . . . . . . . . . . . . . . 14
3.3. Undetected Compromise of CAs or Logs . . . . . . . . . . 15
3.3.1. Compromised CA, Benign Log . . . . . . . . . . . . . 15
3.3.2. Benign CA, Compromised Log . . . . . . . . . . . . . 17
3.3.3. Compromised CA, Compromised Log . . . . . . . . . . . 17
3.4. Attacks Based on Exploiting Multiple Certificate Chains . 18
3.5. Attacks Related to Distribution of Revocation Status . . 20
4. Syntactic mis-issuance . . . . . . . . . . . . . . . . . . . 21
4.1. Non-malicious Web PKI CA context . . . . . . . . . . . . 21
4.1.1. Certificate logged . . . . . . . . . . . . . . . . . 21
4.1.2. Certificate not logged . . . . . . . . . . . . . . . 23
4.2. Malicious Web PKI CA context . . . . . . . . . . . . . . 23
4.2.1. Certificate logged . . . . . . . . . . . . . . . . . 24
4.2.2. Certificate is not logged . . . . . . . . . . . . . . 25
5. Issues Applicable to Sections 3 and 4 . . . . . . . . . . . . 25
5.1. How does a Subject know which Monitor(s) to use? . . . . 25
5.2. How does a Monitor discover new logs? . . . . . . . . . . 25
5.3. CA response to report of a bogus or erroneous certificate 26
5.4. Browser behavior . . . . . . . . . . . . . . . . . . . . 26
5.5. Remediation for a malicious CA . . . . . . . . . . . . . 26
5.6. Auditing - detecting misbehaving logs . . . . . . . . . . 27
6. Security Considerations . . . . . . . . . . . . . . . . . . . 28
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29
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