--- 1/draft-ietf-6man-ipv6-address-generation-privacy-03.txt 2015-02-23 09:14:55.640352971 -0800 +++ 2/draft-ietf-6man-ipv6-address-generation-privacy-04.txt 2015-02-23 09:14:55.676353848 -0800 @@ -1,93 +1,93 @@ Network Working Group A. Cooper Internet-Draft Cisco Intended status: Informational F. Gont -Expires: July 19, 2015 Huawei Technologies +Expires: August 27, 2015 Huawei Technologies D. Thaler Microsoft - January 15, 2015 + February 23, 2015 Privacy Considerations for IPv6 Address Generation Mechanisms - draft-ietf-6man-ipv6-address-generation-privacy-03.txt + draft-ietf-6man-ipv6-address-generation-privacy-04.txt Abstract This document discusses privacy and security considerations for several IPv6 address generation mechanisms, both standardized and non-standardized. It evaluates how different mechanisms mitigate different threats and the trade-offs that implementors, developers, and users face in choosing different addresses or address generation mechanisms. -Status of this Memo +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 July 19, 2015. + This Internet-Draft will expire on August 27, 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 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 3. Weaknesses in IEEE-identifier-based IIDs . . . . . . . . . . . 6 - 3.1. Correlation of activities over time . . . . . . . . . . . 6 - 3.2. Location tracking . . . . . . . . . . . . . . . . . . . . 7 - 3.3. Address scanning . . . . . . . . . . . . . . . . . . . . . 7 - 3.4. Device-specific vulnerability exploitation . . . . . . . . 8 + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 + 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 + 3. Weaknesses in IEEE-identifier-based IIDs . . . . . . . . . . 4 + 3.1. Correlation of activities over time . . . . . . . . . . . 5 + 3.2. Location tracking . . . . . . . . . . . . . . . . . . . . 6 + 3.3. Address scanning . . . . . . . . . . . . . . . . . . . . 6 + 3.4. Device-specific vulnerability exploitation . . . . . . . 7 4. Privacy and security properties of address generation - mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . 9 - 4.1. IEEE-identifier-based IIDs . . . . . . . . . . . . . . . . 11 - 4.2. Static, manually configured IIDs . . . . . . . . . . . . . 11 - 4.3. Constant, semantically opaque IIDs . . . . . . . . . . . . 11 - 4.4. Cryptographically generated IIDs . . . . . . . . . . . . . 12 - 4.5. Stable, semantically opaque IIDs . . . . . . . . . . . . . 12 - 4.6. Temporary IIDs . . . . . . . . . . . . . . . . . . . . . . 12 - 4.7. DHCPv6 generation of IIDs . . . . . . . . . . . . . . . . 13 - 4.8. Transition/co-existence technologies . . . . . . . . . . . 13 - 5. Miscellaneous Issues with IPv6 addressing . . . . . . . . . . 15 - 5.1. Network Operation . . . . . . . . . . . . . . . . . . . . 15 - 5.2. Compliance . . . . . . . . . . . . . . . . . . . . . . . . 15 - 5.3. Intellectual Property Rights (IPRs) . . . . . . . . . . . 15 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 16 - 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 - 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 - 9.1. Normative References . . . . . . . . . . . . . . . . . . . 19 - 9.2. Informative References . . . . . . . . . . . . . . . . . . 20 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 + mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . 7 + 4.1. IEEE-identifier-based IIDs . . . . . . . . . . . . . . . 9 + 4.2. Static, manually configured IIDs . . . . . . . . . . . . 10 + 4.3. Constant, semantically opaque IIDs . . . . . . . . . . . 10 + 4.4. Cryptographically generated IIDs . . . . . . . . . . . . 10 + 4.5. Stable, semantically opaque IIDs . . . . . . . . . . . . 10 + 4.6. Temporary IIDs . . . . . . . . . . . . . . . . . . . . . 11 + 4.7. DHCPv6 generation of IIDs . . . . . . . . . . . . . . . . 12 + 4.8. Transition/co-existence technologies . . . . . . . . . . 12 + 5. Miscellaneous Issues with IPv6 addressing . . . . . . . . . . 12 + 5.1. Network Operation . . . . . . . . . . . . . . . . . . . . 12 + 5.2. Compliance . . . . . . . . . . . . . . . . . . . . . . . 13 + 5.3. Intellectual Property Rights (IPRs) . . . . . . . . . . . 13 + 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 + 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 + 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 + 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 + 9.1. Normative References . . . . . . . . . . . . . . . . . . 13 + 9.2. Informative References . . . . . . . . . . . . . . . . . 15 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction IPv6 was designed to improve upon IPv4 in many respects, and mechanisms for address assignment were one such area for improvement. In addition to static address assignment and DHCP, stateless autoconfiguration was developed as a less intensive, fate-shared means of performing address assignment. With stateless autoconfiguration, routers advertise on-link prefixes and hosts generate their own interface identifiers (IIDs) to complete their @@ -277,22 +278,22 @@ value (0xff, 0xfe) used to form a Modified EUI-64 Interface Identifier, greatly help to reduce the search space, making it easier for an attacker to scan for individual addresses using widely-known popular OUIs. This erases much of the protection against address scanning that the larger IPv6 address space was supposed to provide as compared to IPv4. 3.4. Device-specific vulnerability exploitation IPv6 addresses that embed IEEE identifiers leak information about the - device (Network Interface Card vendor, or even Operating System - and/or software type), which could be leveraged by an attacker with + device (Network Interface Card vendor, or even Operating System and/ + or software type), which could be leveraged by an attacker with knowledge of device/software-specific vulnerabilities to quickly find possible targets. Attackers can exploit vulnerabilities in hosts whose IIDs they have previously obtained, or scan an address space to find potential targets. 4. Privacy and security properties of address generation mechanisms Analysis of the extent to which a particular host is protected against the threats described in Section 3 depends on how each of a host's addresses is generated and used. In some scenarios, a host @@ -448,27 +449,32 @@ public key and the chosen modifier block, since it is possible to rotate modifier blocks without generating new public keys. Because the cryptographic hash of the host's public key uses the subnet prefix as an input, even if the host does not generate a new public key or modifier block when it moves to a different network, its location cannot be tracked via the IID. CGAs do not allow device- specific exploitation or address scanning attacks. 4.5. Stable, semantically opaque IIDs - [RFC7217] specifies a mechanism that generates a unique random IID - for each network. A host that stays connected to the same network - could therefore be tracked at length, whereas a mobile host's - activities could only be correlated for the duration of each network - connection. Location tracking is not possible with these addresses. - They also do not allow device-specific exploitation or address - scanning attacks. + [RFC7217] specifies an algorithm that generates, for each network + interface, a unique random IID per network. The aforementioned + algorithm is employed not only for global unicast addresses, but also + for unique local unicast addresses and link-local unicast addresses, + since these addresses may leak out via application protocols (e.g., + IPv6 addresses embedded in email headers). + + A host that stays connected to the same network could therefore be + tracked at length, whereas a mobile host's activities could only be + correlated for the duration of each network connection. Location + tracking is not possible with these addresses. They also do not + allow device-specific exploitation or address scanning attacks. 4.6. Temporary IIDs A host that uses only a temporary address mitigates all four threats. Its activities may only be correlated for the lifetime a single temporary address. A host that configures both an IEEE-identifier-based IID and temporary addresses makes the host vulnerable to the same attacks as if temporary addresses were not in use, although the viability of @@ -596,39 +602,39 @@ Autoconfiguration", RFC 2462, December 1998. [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet Networks", RFC 2464, December 1998. [RFC3041] Narten, T. and R. Draves, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 3041, January 2001. [RFC3314] Wasserman, M., "Recommendations for IPv6 in Third - Generation Partnership Project (3GPP) Standards", - RFC 3314, September 2002. + Generation Partnership Project (3GPP) Standards", RFC + 3314, September 2002. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [RFC3484] Draves, R., "Default Address Selection for Internet Protocol version 6 (IPv6)", RFC 3484, February 2003. [RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure Neighbor Discovery (SEND)", RFC 3971, March 2005. [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", RFC 3972, March 2005. [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through - Network Address Translations (NATs)", RFC 4380, - February 2006. + Network Address Translations (NATs)", RFC 4380, February + 2006. [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 4941, September 2007. [RFC5991] Thaler, D., Krishnan, S., and J. Hoagland, "Teredo Security Updates", RFC 5991, September 2010. [RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265, April 2011. @@ -640,57 +646,58 @@ [RFC7136] Carpenter, B. and S. Jiang, "Significance of IPv6 Interface Identifiers", RFC 7136, February 2014. [RFC7217] Gont, F., "A Method for Generating Semantically Opaque Interface Identifiers with IPv6 Stateless Address Autoconfiguration (SLAAC)", RFC 7217, April 2014. 9.2. Informative References [Broersma] - Broersma, R., "IPv6 Everywhere: Living with a Fully IPv6- - enabled environment", Australian IPv6 Summit 2010, - Melbourne, VIC Australia, October 2010, October 2010, . + Broersma, R., "IPv6 Everywhere: Living with a Fully + IPv6-enabled environment", Australian IPv6 Summit 2010, + Melbourne, VIC Australia, October 2010, October 2010, + . [CGA-IPR] IETF, "Intellectual Property Rights on RFC 3972", 2005. [I-D.ietf-dhc-stable-privacy-addresses] Gont, F. and W. Will, "A Method for Generating Semantically Opaque Interface Identifiers with Dynamic - Host Configuration Protocol for IPv6 (DHCPv6)", - draft-ietf-dhc-stable-privacy-addresses-00 (work in - progress), October 2014. + Host Configuration Protocol for IPv6 (DHCPv6)", draft- + ietf-dhc-stable-privacy-addresses-01 (work in progress), + February 2015. [I-D.ietf-opsec-ipv6-host-scanning] Gont, F. and T. Chown, "Network Reconnaissance in IPv6 - Networks", draft-ietf-opsec-ipv6-host-scanning-04 (work in - progress), June 2014. + Networks", draft-ietf-opsec-ipv6-host-scanning-06 (work in + progress), February 2015. [KAME-CGA] KAME, "The KAME IPR policy and concerns of some technologies which have IPR claims", 2005, . [Microsoft] Microsoft, "IPv6 interface identifiers", 2013, . [Panopticlick] Electronic Frontier Foundation, "Panopticlick", 2011, . [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., Morris, J., Hansen, M., and R. Smith, "Privacy - Considerations for Internet Protocols", RFC 6973, - July 2013. + Considerations for Internet Protocols", RFC 6973, July + 2013. [RFC7421] Carpenter, B., Chown, T., Gont, F., Jiang, S., Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit Boundary in IPv6 Addressing", RFC 7421, January 2015. Authors' Addresses Alissa Cooper Cisco 707 Tasman Drive