Network Reconnaissance in IPv6 Networks
RFC 7707
| Document | Type |
RFC - Informational
(March 2016; No errata)
Obsoletes RFC 5157
|
|
|---|---|---|---|
| Last updated | 2016-03-09 | ||
| Replaces | draft-gont-opsec-ipv6-host-scanning | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Gunter Van de Velde | ||
| Shepherd write-up | Show (last changed 2015-05-30) | ||
| IESG | IESG state | RFC 7707 (Informational) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Joel Jaeggli | ||
| Send notices to | (None) | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | No IC | ||
Internet Engineering Task Force (IETF) F. Gont
Request for Comments: 7707 Huawei Technologies
Obsoletes: 5157 T. Chown
Category: Informational Jisc
ISSN: 2070-1721 March 2016
Network Reconnaissance in IPv6 Networks
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 fewer unique addresses. As a
result, it is widely assumed that it would take a tremendous effort
to perform address-scanning attacks against IPv6 networks; therefore,
IPv6 address-scanning attacks have been considered unfeasible. This
document formally obsoletes 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.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7707.
Gont & Chown Informational [Page 1]
RFC 7707 IPv6 Reconnaissance March 2016
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
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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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Requirements for the Applicability of Network Reconnaissance
Techniques . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. IPv6 Address Scanning . . . . . . . . . . . . . . . . . . . . 6
4.1. Address Configuration in IPv6 . . . . . . . . . . . . . . 6
4.1.1. Stateless Address Autoconfiguration (SLAAC) . . . . . 6
4.1.2. Dynamic Host Configuration Protocol for IPv6 (DHCPv6) 11
4.1.3. Manually Configured Addresses . . . . . . . . . . . . 12
4.1.4. IPv6 Addresses Corresponding to
Transition/Coexistence Technologies . . . . . . . . . 14
4.1.5. IPv6 Address Assignment in Real-World Network
Scenarios . . . . . . . . . . . . . . . . . . . . . . 14
4.2. IPv6 Address Scanning of Remote Networks . . . . . . . . 17
4.2.1. Reducing the Subnet ID Search Space . . . . . . . . . 18
4.3. IPv6 Address Scanning of Local Networks . . . . . . . . . 19
4.4. Existing IPv6 Address-Scanning Tools . . . . . . . . . . 20
4.4.1. Remote IPv6 Network Address Scanners . . . . . . . . 20
4.4.2. Local IPv6 Network Address Scanners . . . . . . . . . 21
4.5. Mitigations . . . . . . . . . . . . . . . . . . . . . . . 21
4.6. Conclusions . . . . . . . . . . . . . . . . . . . . . . . 22
5. Alternative Methods to Glean IPv6 Addresses . . . . . . . . . 23
5.1. Leveraging the Domain Name System (DNS) for Network
Reconnaissance . . . . . . . . . . . . . . . . . . . . . 23
5.1.1. DNS Advertised Hosts . . . . . . . . . . . . . . . . 23
5.1.2. DNS Zone Transfers . . . . . . . . . . . . . . . . . 23
5.1.3. DNS Brute Forcing . . . . . . . . . . . . . . . . . . 23
5.1.4. DNS Reverse Mappings . . . . . . . . . . . . . . . . 24
5.2. Leveraging Local Name Resolution and Service Discovery
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