draft-ietf-6man-stable-privacy-addresses-01.txt   draft-ietf-6man-stable-privacy-addresses-02.txt 
IPv6 maintenance Working Group (6man) F. Gont IPv6 maintenance Working Group (6man) F. Gont
Internet-Draft SI6 Networks / UTN-FRH Internet-Draft SI6 Networks / UTN-FRH
Intended status: Standards Track October 8, 2012 Intended status: Standards Track December 30, 2012
Expires: April 11, 2013 Expires: July 3, 2013
A method for Generating Stable Privacy-Enhanced Addresses with IPv6 A method for Generating Stable Privacy-Enhanced Addresses with IPv6
Stateless Address Autoconfiguration (SLAAC) Stateless Address Autoconfiguration (SLAAC)
draft-ietf-6man-stable-privacy-addresses-01 draft-ietf-6man-stable-privacy-addresses-02
Abstract Abstract
This document specifies a method for generating IPv6 Interface This document specifies a method for generating IPv6 Interface
Identifiers to be used with IPv6 Stateless Address Autoconfiguration Identifiers to be used with IPv6 Stateless Address Autoconfiguration
(SLAAC), such that addresses configured using this method are stable (SLAAC), such that addresses configured using this method are stable
within each subnet, but the Interface Identifier changes when hosts within each subnet, but the Interface Identifier changes when hosts
move from one network to another. The aforementioned method is meant move from one network to another. The aforementioned method is meant
to be an alternative to generating Interface Identifiers based on to be an alternative to generating Interface Identifiers based on
IEEE identifiers, such that the benefits of stable addresses can be IEEE identifiers, such that the benefits of stable addresses can be
skipping to change at page 1, line 38 skipping to change at page 1, line 38
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 11, 2013. This Internet-Draft will expire on July 3, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Design goals . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Design goals . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Algorithm specification . . . . . . . . . . . . . . . . . . . 6 3. Algorithm specification . . . . . . . . . . . . . . . . . . . 7
4. Resolving Duplicate Address Detection (DAD) conflicts . . . . 9 4. Resolving Duplicate Address Detection (DAD) conflicts . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . . 13 8.1. Normative References . . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . . 13 8.2. Informative References . . . . . . . . . . . . . . . . . . 14
Appendix A. Privacy issues still present with RFC 4941 . . . . . 15 Appendix A. Privacy issues still present with RFC 4941 . . . . . 16
A.1. Host tracking . . . . . . . . . . . . . . . . . . . . . . 15 A.1. Host tracking . . . . . . . . . . . . . . . . . . . . . . 16
A.1.1. Tracking hosts across networks #1 . . . . . . . . . . 15 A.1.1. Tracking hosts across networks #1 . . . . . . . . . . 16
A.1.2. Tracking hosts across networks #2 . . . . . . . . . . 15 A.1.2. Tracking hosts across networks #2 . . . . . . . . . . 16
A.1.3. Revealing the identity of devices performing A.1.3. Revealing the identity of devices performing
server-like functions . . . . . . . . . . . . . . . . 16 server-like functions . . . . . . . . . . . . . . . . 17
A.2. Address scanning attacks . . . . . . . . . . . . . . . . . 16 A.2. Address scanning attacks . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 17 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction 1. Introduction
[RFC4862] specifies the Stateless Address Autoconfiguration (SLAAC) [RFC4862] specifies the Stateless Address Autoconfiguration (SLAAC)
for IPv6 [RFC2460], which typically results in hosts configuring one for IPv6 [RFC2460], which typically results in hosts configuring one
or more "stable" addresses composed of a network prefix advertised by or more "stable" addresses composed of a network prefix advertised by
a local router, and an Interface Identifier (IID) that typically a local router, and an Interface Identifier (IID) that typically
embeds a hardware address (e.g., using IEEE identifiers) [RFC4291]. embeds a hardware address (e.g., using IEEE identifiers) [RFC4291].
Generally, static addresses are thought to simplify network Generally, stable addresses are thought to simplify network
management, since they simplify Access Control Lists (ACLs) and management, since they simplify Access Control Lists (ACLs) and
logging. However, since IEEE identifiers are typically globally logging. However, since IEEE identifiers are typically globally
unique, the resulting IPv6 addresses can be leveraged to track and unique, the resulting IPv6 addresses can be leveraged to track and
correlate the activity of a node over time and across multiple correlate the activity of a node over time and across multiple
subnets and networks, thus negatively affecting the privacy of users. subnets and networks, thus negatively affecting the privacy of users.
The "Privacy Extensions for Stateless Address Autoconfiguration in The "Privacy Extensions for Stateless Address Autoconfiguration in
IPv6" [RFC4941] were introduced to complicate the task of IPv6" [RFC4941] were introduced to complicate the task of
eavesdroppers and other information collectors to correlate the eavesdroppers and other information collectors to correlate the
activities of a node, and basically result in temporary (and random) activities of a node, and basically result in temporary (and random)
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to negatively affect user privacy, but rather a desire to simplify to negatively affect user privacy, but rather a desire to simplify
operation of the network (simplify the use of ACLs, logging, etc.). operation of the network (simplify the use of ACLs, logging, etc.).
This document specifies a method to generate interface identifiers This document specifies a method to generate interface identifiers
that are stable/constant within each subnet, but that change as hosts that are stable/constant within each subnet, but that change as hosts
move from one network to another, thus keeping the "stability" move from one network to another, thus keeping the "stability"
properties of the interface identifiers specified in [RFC4291], while properties of the interface identifiers specified in [RFC4291], while
still mitigating host-scanning attacks and preventing correlation of still mitigating host-scanning attacks and preventing correlation of
the activities of a node as it moves from one network to another. the activities of a node as it moves from one network to another.
This document does not update or modify IPv6 StateLess Address Auto-
Configuration (SLAAC) [RFC4862] itself, but rather only specifies an
alternative algorithm to generate Interface IDs. Therefore, the
usual address lifetime properties (as specified in the corresponding
Prefix Information Options) apply when IPv6 addresses are generated
as a result of employing the algorithm specified in this document
with SLAAC [RFC4862]. Additionally, from the point of view of
renumbering, we note that these addresses behave like the traditional
IPv6 addresses (that embed a hardware address) resulting from SLAAC
[RFC4862].
For nodes that currently disable "Privacy extensions" [RFC4941] for For nodes that currently disable "Privacy extensions" [RFC4941] for
some of the reasons stated above, this mechanism provides stable some of the reasons stated above, this mechanism provides stable
privacy-enhanced addresses which may already address most of the privacy-enhanced addresses which may already address most of the
privacy concerns related to addresses that embed IEEE identifiers privacy concerns related to addresses that embed IEEE identifiers
[RFC4291]. On the other hand, in scenarios in which "Privacy [RFC4291]. On the other hand, in scenarios in which "Privacy
Extensions" are employed, implementation of the mechanism described Extensions" are employed, implementation of the mechanism described
in this document would mitigate host-scanning attacks and also in this document would mitigate host-scanning attacks and also
mitigate correlation of host activities. mitigate correlation of host activities.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
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(see Appendix A). (see Appendix A).
3. Algorithm specification 3. Algorithm specification
IPv6 implementations conforming to this specification MUST generate IPv6 implementations conforming to this specification MUST generate
interface identifiers using the algorithm specified in this section interface identifiers using the algorithm specified in this section
in replacement of any other algorithms used for generating "stable" in replacement of any other algorithms used for generating "stable"
addresses (such as that specified in [RFC2464]). The aforementioned addresses (such as that specified in [RFC2464]). The aforementioned
algorithm MUST be employed for generating the interface identifiers algorithm MUST be employed for generating the interface identifiers
for all of the IPv6 addresses configured with SLAAC for a given for all of the IPv6 addresses configured with SLAAC for a given
interface, including IPv6 link-local addresses. Implementations interface, including IPv6 link-local addresses.
conforming to this specification SHOULD provide the means for a
system administrator to enable or disable the use of this algorithm This means that this document does not formally obsolete or
for generating Interface Identifiers. Implementations conforming to deprecate any of the existing algorithms to generate Interface IDs
this specification MAY employ the algorithm specified in [RFC4941] to (e.g. such as that specified in [RFC2464]). However, those IPv6
generate temporary addresses in addition to the addresses generated implementations that employ this specification must generate all
with the algorithm specified in this document. of their "stable" addresses as specified in this document.
Implementations conforming to this specification SHOULD provide the
means for a system administrator to enable or disable the use of this
algorithm for generating Interface Identifiers. Implementations
conforming to this specification MAY employ the algorithm specified
in [RFC4941] to generate temporary addresses in addition to the
addresses generated with the algorithm specified in this document.
Unless otherwise noted, all of the parameters included in the Unless otherwise noted, all of the parameters included in the
expression below MUST be included when generating an Interface ID. expression below MUST be included when generating an Interface ID.
1. Compute a random (but stable) identifier with the expression: 1. Compute a random (but stable) identifier with the expression:
RID = F(Prefix, Interface_Index, Network_ID, DAD_Counter, RID = F(Prefix, Interface_Index, Network_ID, DAD_Counter,
secret_key) secret_key)
Where: Where:
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Some network specific data that identifies the subnet to which Some network specific data that identifies the subnet to which
this interface is attached. For example the IEEE 802.11 this interface is attached. For example the IEEE 802.11
Service Set Identifier (SSID) corresponding to the network to Service Set Identifier (SSID) corresponding to the network to
which this interface is associated. This parameter is which this interface is associated. This parameter is
OPTIONAL. OPTIONAL.
DAD_Counter: DAD_Counter:
A counter that is employed to resolve Duplicate Address A counter that is employed to resolve Duplicate Address
Detection (DAD) conflicts. It MUST be initialized to 0, and Detection (DAD) conflicts. It MUST be initialized to 0, and
incremented by 1 for each new tentative address that is incremented by 1 for each new tentative address that is
configured as a result of a DAD conflict. See Section 4 for configured as a result of a DAD conflict. Implementations
additional details. that record DAD_Counter in non-volatile memory for each
{Prefix, Interface_Index, Network_ID} tuple MUST initialize
DAD_Counter to the recorded value if such an entry exists in
non-volatile memory). See Section 4 for additional details.
secret_key: secret_key:
A secret key that is not known by the attacker. The secret A secret key that is not known by the attacker. The secret
key MUST be initialized at system installation time to a key MUST be initialized at system installation time to a
pseudo-random number (see [RFC4086] for randomness pseudo-random number (see [RFC4086] for randomness
requirements for security). An implementation MAY provide the requirements for security). An implementation MAY provide the
means for the user to change the secret key. means for the user to change the secret key.
2. The Interface Identifier is finally obtained by taking the 2. The Interface Identifier is finally obtained by taking the
leftmost 64 bits of the RID value computed in the previous step, leftmost 64 bits of the RID value computed in the previous step,
and and setting bit 6 (the leftmost bit is numbered 0) to zero. and and setting bit 6 (the leftmost bit is numbered 0) to zero.
This creates an interface identifier with the universal/local bit This creates an interface identifier with the universal/local bit
indicating local significance only. indicating local significance only. The resulting Interface
Identifier should be compared against a list of reserved
interface identifiers and to those already employed in an address
of the same network interface and the same network prefix. In
the event that an unacceptable identifier has been generated,
this situation should be handled in the same way as the case of
duplicate addresses (see Section 4).
This document does not require the use of any specific PRF for the
function F() above, since the choice of such PRF is usually a trade-
off between a number of properties (processing requirements, ease of
implementation, possible intellectual property rights, etc.), and
since the best possible choice for F() might be different for
different types of devices (e.g. embedded systems vs. regular
servers) and might possibly change over time.
Note that the result of F() in the algorithm above is no more secure Note that the result of F() in the algorithm above is no more secure
than the secret key. If an attacker is aware of the PRF that is than the secret key. If an attacker is aware of the PRF that is
being used by the victim (which we should expect), and the attacker being used by the victim (which we should expect), and the attacker
can obtain enough material (i.e. addresses configured by the victim), can obtain enough material (i.e. addresses configured by the victim),
the attacker may simply search the entire secret-key space to find the attacker may simply search the entire secret-key space to find
matches. To protect against this, the secret key should be of a matches. To protect against this, the secret key should be of a
reasonable length. Key lengths of at least 128 bits should be reasonable length. Key lengths of at least 128 bits should be
adequate. The secret key is initialized at system installation time adequate. The secret key is initialized at system installation time
to a pseudo-random number, thus allowing this mechanism to be to a pseudo-random number, thus allowing this mechanism to be
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benefit from predictable Interface IDs (such as host scanning). benefit from predictable Interface IDs (such as host scanning).
Including the optional Network_ID parameter when computing the RID Including the optional Network_ID parameter when computing the RID
value above would cause the algorithm to produce a different value above would cause the algorithm to produce a different
Interface Identifier when connecting to different networks, even when Interface Identifier when connecting to different networks, even when
configuring addresses belonging to the same prefix. This means that configuring addresses belonging to the same prefix. This means that
a host would employ a different Interface ID as it moves from one a host would employ a different Interface ID as it moves from one
network to another even for IPv6 link-local addresses or Unique Local network to another even for IPv6 link-local addresses or Unique Local
Addresses (ULAs). Addresses (ULAs).
Note that there are a number of ways in which these addresses
might leak out. For example, an attacker could use ICMPv6 Node
Information queries [RFC4620] to obtain such addresses.
4. Resolving Duplicate Address Detection (DAD) conflicts 4. Resolving Duplicate Address Detection (DAD) conflicts
If as a result of performing Duplicate Address Detection (DAD) If as a result of performing Duplicate Address Detection (DAD)
[RFC4862] a host finds that the tentative address generated with the [RFC4862] a host finds that the tentative address generated with the
algorithm specified in Section 3 is a duplicate address, it MAY algorithm specified in Section 3 is a duplicate address, it SHOULD
resolve the address conflict by trying a new tentative address as resolve the address conflict by trying a new tentative address as
follows: follows:
o DAD_Counter is incremented by 1. o DAD_Counter is incremented by 1.
o A new Interface ID is generated with the algorithm specified in o A new Interface ID is generated with the algorithm specified in
Section 3, using the incremented DAD_Counter value. Section 3, using the incremented DAD_Counter value.
This procedure may be repeated a number of times until the address This procedure may be repeated a number of times until the address
conflict is resolved. However, hosts MUST limit the number of conflict is resolved. We RECOMMEND hosts to try at least
tentative addresses that are tried (rather than indefinitely try a IDGEN_RETRIES (hereby specified as "3") tentative addresses if DAD
fails for successive generated addresses, in the hopes of resolving
the address conflict. We also note that hosts MUST limit the number
of tentative addresses that are tried (rather than indefinitely try a
new tentative address until the conflict is resolved). new tentative address until the conflict is resolved).
In those (unlikely) scenarios in which duplicate addresses are In those (unlikely) scenarios in which duplicate addresses are
detected and in which the order in which the conflicting nodes detected and in which the order in which the conflicting nodes
configure their addresses may vary (e.g., because they may be configure their addresses may vary (e.g., because they may be
bootstrapped in different order), the algorithm specified in this bootstrapped in different order), the algorithm specified in this
section for resolving DAD conflicts could lead to addresses that are section for resolving DAD conflicts could lead to addresses that are
not stable within the same subnet. In order to mitigate this not stable within the same subnet. In order to mitigate this
potential problem, nodes MAY record the DAD_Counter value employed potential problem, nodes MAY record the DAD_Counter value employed
for a specific {Prefix, Interface_Index, Network_ID} tuple in non- for a specific {Prefix, Interface_Index, Network_ID} tuple in non-
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5. IANA Considerations 5. IANA Considerations
There are no IANA registries within this document. The RFC-Editor There are no IANA registries within this document. The RFC-Editor
can remove this section before publication of this document as an can remove this section before publication of this document as an
RFC. RFC.
6. Security Considerations 6. Security Considerations
This document specifies an algorithm for generating interface This document specifies an algorithm for generating interface
identifiers to be used with IPv6 Stateless Address Autoconfiguration identifiers to be used with IPv6 Stateless Address Autoconfiguration
(SLAAC), in replacement of e.g. interface identifiers that embed IEEE (SLAAC), as an alternative to e.g. interface identifiers that embed
identifiers (such as those specified in [RFC2464]). When compared to IEEE identifiers (such as those specified in [RFC2464]). When
such identifiers, the identifiers specified in this document have a compared to such identifiers, the identifiers specified in this
number of advantages: document have a number of advantages:
o They prevent trivial host-tracking, since when a host moves from o They prevent trivial host-tracking, since when a host moves from
one network to another the network prefix used for one network to another the network prefix used for
autoconfiguration and/or the Network ID (e.g., IEEE 802.11 SSID) autoconfiguration and/or the Network ID (e.g., IEEE 802.11 SSID)
will typically change, and hence the resulting interface will typically change, and hence the resulting interface
identifier will also change (see Appendix A. identifier will also change (see Appendix A.
o They mitigate host-scanning techniques which leverage predictable o They mitigate address-scanning techniques which leverage
interface identifiers (e.g., known Organizational Unique predictable interface identifiers (e.g., known Organizational
Identifiers). Unique Identifiers) [I-D.ietf-opsec-ipv6-host-scanning].
o They result in IPv6 addresses that are independent of the o They result in IPv6 addresses that are independent of the
underlying hardware (i.e. the resulting IPv6 addresses do not underlying hardware (i.e. the resulting IPv6 addresses do not
change if a network interface card is replaced). change if a network interface card is replaced).
We note that this algorithm is meant to replace interface identifiers We note that this algorithm is meant to be an alternative to
such as those specified in [RFC2464], but not the temporary-addresses interface identifiers such as those specified in [RFC2464], but is
such as those specified in [RFC4941]. Clearly, temporary addresses not meant as an alternative to temporary Interface IDs (such as those
may help to mitigate the correlation of activities of a node within specified in [RFC4941]). Clearly, temporary addresses may help to
the same network, and may also reduce the attack exposure window mitigate the correlation of activities of a node within the same
(since the lifetime of privacy/temporary IPv6 address is reduced when network, and may also reduce the attack exposure window (since
compared to that of addresses generated with the method specified in privacy/temporary addresses are short-lived when compared to the
this document). We note that implementation of this algorithm would addresses generated with the method specified in this document). We
still benefit those hosts employing "Privacy Addresses", since it note that implementation of this algorithm would still benefit those
would mitigate host-tracking vectors still present when privacy hosts employing "Privacy Addresses", since it would mitigate host-
addresses are used (Appendix A, and would also mitigate host-scanning tracking vectors still present when privacy addresses are used
techniques that leverage patterns in IPv6 addresses that embed IEEE (Appendix A, and would also mitigate host-scanning techniques that
identifiers. leverage patterns in IPv6 addresses that embed IEEE identifiers.
Finally, we note that the method described in this document may Finally, we note that the method described in this document may
mitigate most of the privacy concerns arising from the use of IPv6 mitigate most of the privacy concerns arising from the use of IPv6
addresses that embed IEEE identifiers, without the use of temporary addresses that embed IEEE identifiers, without the use of temporary
addresses, thus possibly offering an interesting trade-off for those addresses, thus possibly offering an interesting trade-off for those
scenarios in which the use of temporary addresses is not feasible. scenarios in which the use of temporary addresses is not feasible.
7. Acknowledgements 7. Acknowledgements
The algorithm specified in this document has been inspired by Steven
Bellovin's work [RFC1948] in the area of TCP sequence numbers.
The author would like to thank (in alphabetical order) Karl Auer, The author would like to thank (in alphabetical order) Karl Auer,
Steven Bellovin, Matthias Bethke, Dominik Elsbroek, Bob Hinden, Steven Bellovin, Matthias Bethke, Brian Carpenter, Dominik Elsbroek,
Christian Huitema, Ray Hunter, Jong-Hyouk Lee, and Michael Bob Hinden, Christian Huitema, Ray Hunter, Jong-Hyouk Lee, Michael
Richardson, for providing valuable comments on earlier versions of Richardson, and Ole Troan, for providing valuable comments on earlier
this document. versions of this document.
This document is based on the technical report "Security Assessment This document is based on the technical report "Security Assessment
of the Internet Protocol version 6 (IPv6)" [CPNI-IPv6] authored by of the Internet Protocol version 6 (IPv6)" [CPNI-IPv6] authored by
Fernando Gont on behalf of the UK Centre for the Protection of Fernando Gont on behalf of the UK Centre for the Protection of
National Infrastructure (CPNI). National Infrastructure (CPNI).
Fernando Gont would like to thank CPNI (http://www.cpni.gov.uk) for Fernando Gont would like to thank CPNI (http://www.cpni.gov.uk) for
their continued support. their continued support.
8. References 8. References
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[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007. Address Autoconfiguration", RFC 4862, September 2007.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007. IPv6", RFC 4941, September 2007.
8.2. Informative References 8.2. Informative References
[RFC1948] Bellovin, S., "Defending Against Sequence Number Attacks",
RFC 1948, May 1996.
[RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet
Networks", RFC 2464, December 1998. Networks", RFC 2464, December 1998.
[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W. [RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
Stevens, "Basic Socket Interface Extensions for IPv6", Stevens, "Basic Socket Interface Extensions for IPv6",
RFC 3493, February 2003. RFC 3493, February 2003.
[RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei, [RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei,
"Advanced Sockets Application Program Interface (API) for "Advanced Sockets Application Program Interface (API) for
IPv6", RFC 3542, May 2003. IPv6", RFC 3542, May 2003.
[RFC4620] Crawford, M. and B. Haberman, "IPv6 Node Information [I-D.ietf-opsec-ipv6-host-scanning]
Queries", RFC 4620, August 2006. Gont, F. and T. Chown, "Network Reconnaissance in IPv6
Networks", draft-ietf-opsec-ipv6-host-scanning-00 (work in
[I-D.gont-opsec-ipv6-host-scanning] progress), December 2012.
Gont, F., "Network Reconnaissance in IPv6 Networks",
draft-gont-opsec-ipv6-host-scanning-01 (work in progress),
July 2012.
[Gont-DEEPSEC2011] [Gont-DEEPSEC2011]
Gont, "Results of a Security Assessment of the Internet Gont, "Results of a Security Assessment of the Internet
Protocol version 6 (IPv6)", DEEPSEC 2011 Conference, Protocol version 6 (IPv6)", DEEPSEC 2011 Conference,
Vienna, Austria, November 2011, <http:// Vienna, Austria, November 2011, <http://
www.si6networks.com/presentations/deepsec2011/ www.si6networks.com/presentations/deepsec2011/
fgont-deepsec2011-ipv6-security.pdf>. fgont-deepsec2011-ipv6-security.pdf>.
[Gont-BRUCON2012] [Gont-BRUCON2012]
Gont, "Recent Advances in IPv6 Security", BRUCON 2012 Gont, "Recent Advances in IPv6 Security", BRUCON 2012
skipping to change at page 16, line 41 skipping to change at page 17, line 41
The scheme proposed in this document prevents such information The scheme proposed in this document prevents such information
leakage by causing nodes to generate different Interface-IDs when leakage by causing nodes to generate different Interface-IDs when
moving to one network to another, thus mitigating this kind of moving to one network to another, thus mitigating this kind of
privacy attack. privacy attack.
A.2. Address scanning attacks A.2. Address scanning attacks
While it is usually assumed that address-scanning attacks are While it is usually assumed that address-scanning attacks are
unfeasible, an attacker could leverage patterns in IPv6 addresses to unfeasible, an attacker could leverage patterns in IPv6 addresses to
greatly reduce the search space [I-D.gont-opsec-ipv6-host-scanning] greatly reduce the search space [I-D.ietf-opsec-ipv6-host-scanning]
[Gont-BRUCON2012]. [Gont-BRUCON2012].
As noted earlier in this document, privacy/temporary addresses do not As noted earlier in this document, privacy/temporary addresses do not
eliminate the use of IPv6 addresses that embed IEEE identifiers, and eliminate the use of IPv6 addresses that embed IEEE identifiers, and
hence such hosts would still be vulnerable to address-scanning hence such hosts would still be vulnerable to address-scanning
attacks. The method specified in this document eliminates such attacks. The method specified in this document eliminates such
patterns and would thus mitigate the aforementioned address-scanning patterns and would thus mitigate the aforementioned address-scanning
attacks. attacks.
Author's Address Author's Address
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