Network Reconnaissance in IPv6 Networks
draft-ietf-opsec-ipv6-host-scanning-06

The information below is for an old version of the document
Document Type Active Internet-Draft (opsec WG)
Authors Fernando Gont  , Tim Chown 
Last updated 2015-02-05
Replaces draft-gont-opsec-ipv6-host-scanning
Stream IETF
Intended RFC status Informational
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Document shepherd Gunter Van de Velde
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opsec                                                            F. Gont
Internet-Draft                                       Huawei Technologies
Obsoletes: 5157 (if approved)                                   T. Chown
Intended status: Informational                 University of Southampton
Expires: August 9, 2015                                 February 5, 2015

                Network Reconnaissance in IPv6 Networks
                 draft-ietf-opsec-ipv6-host-scanning-06

Abstract

   IPv6 offers a much larger address space than that of its IPv4
   counterpart.  An IPv6 subnet of size /64 can (in theory) accommodate
   approximately 1.844 * 10^19 hosts, thus resulting in a much lower
   host density (#hosts/#addresses) than is typical in IPv4 networks,
   where a site typically has 65,000 or less unique addresses.  As a
   result, it is widely assumed that it would take a tremendous effort
   to perform address scanning attacks against IPv6 networks, and
   therefore brute-force IPv6 address scanning attacks have been
   considered unfeasible.  This document updates RFC 5157, which first
   discussed this assumption, by providing further analysis on how
   traditional address scanning techniques apply to IPv6 networks, and
   exploring some additional techniques that can be employed for IPv6
   network reconnaissance.  In doing so, this document formally
   obsoletes RFC 5157.

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 August 9, 2015.

Gont & Chown             Expires August 9, 2015                 [Page 1]
Internet-Draft             IPv6 Reconnaissance             February 2015

Copyright Notice

   Copyright (c) 2015 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
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   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
   2.  Requirements for the Applicability of Network Reconnaissance
       Techniques  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  IPv6 Address Scanning . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Address Configuration in IPv6 . . . . . . . . . . . . . .   6
       3.1.1.  StateLess Address Auto-Configuration (SLAAC)  . . . .   6
       3.1.2.  Dynamic Host Configuration Protocol version 6
               (DHCPv6)  . . . . . . . . . . . . . . . . . . . . . .  10
       3.1.3.  Manually-configured Addresses . . . . . . . . . . . .  10
       3.1.4.  IPv6 Addresses Corresponding to Transition/Co-
               existence Technologies  . . . . . . . . . . . . . . .  12
       3.1.5.  IPv6 Address Assignment in Real-world Network
               Scenarios . . . . . . . . . . . . . . . . . . . . . .  13
     3.2.  IPv6 Address Scanning of Remote Networks  . . . . . . . .  16
       3.2.1.  Reducing the subnet ID search space . . . . . . . . .  16
     3.3.  IPv6 Address Scanning of Local Networks . . . . . . . . .  17
     3.4.  Existing IPv6 Address Scanning Tools  . . . . . . . . . .  18
       3.4.1.  Remote IPv6 Network Scanners  . . . . . . . . . . . .  18
       3.4.2.  Local IPv6 Network Scanners . . . . . . . . . . . . .  19
     3.5.  Mitigations . . . . . . . . . . . . . . . . . . . . . . .  19
   4.  Leveraging the Domain Name System (DNS) for Network
       Reconnaissance  . . . . . . . . . . . . . . . . . . . . . . .  20
     4.1.  DNS Advertised Hosts  . . . . . . . . . . . . . . . . . .  20
     4.2.  DNS Zone Transfers  . . . . . . . . . . . . . . . . . . .  21
     4.3.  DNS Brute Forcing . . . . . . . . . . . . . . . . . . . .  21
     4.4.  DNS Reverse Mappings  . . . . . . . . . . . . . . . . . .  21
   5.  Leveraging Local Name Resolution and Service Discovery
       Services  . . . . . . . . . . . . . . . . . . . . . . . . . .  21
   6.  Public Archives . . . . . . . . . . . . . . . . . . . . . . .  22
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