Internet DRAFT - draft-ietf-dprive-problem-statement
draft-ietf-dprive-problem-statement
DNS PRIVate Exchange (dprive) Working Group S. Bortzmeyer
Internet-Draft AFNIC
Intended status: Informational June 15, 2015
Expires: December 17, 2015
DNS privacy considerations
draft-ietf-dprive-problem-statement-06
Abstract
This document describes the privacy issues associated with the use of
the DNS by Internet users. It is intended to be an analysis of the
present situation and does not prescribe solutions.
Status of This Memo
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This Internet-Draft will expire on December 17, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. The alleged public nature of DNS data . . . . . . . . . . 5
2.2. Data in the DNS request . . . . . . . . . . . . . . . . . 5
2.3. Cache snooping . . . . . . . . . . . . . . . . . . . . . 6
2.4. On the wire . . . . . . . . . . . . . . . . . . . . . . . 7
2.5. In the servers . . . . . . . . . . . . . . . . . . . . . 8
2.5.1. In the recursive resolvers . . . . . . . . . . . . . 9
2.5.2. In the authoritative name servers . . . . . . . . . . 9
2.5.3. Rogue servers . . . . . . . . . . . . . . . . . . . . 10
2.6. Re-identification and other inferences . . . . . . . . . 11
3. Actual "attacks" . . . . . . . . . . . . . . . . . . . . . . 11
4. Legalities . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Security considerations . . . . . . . . . . . . . . . . . . . 12
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
8.1. Normative References . . . . . . . . . . . . . . . . . . 13
8.2. Informative References . . . . . . . . . . . . . . . . . 13
8.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
This document is an analysis of the DNS privacy issues, in the spirit
of section 8 of [RFC6973].
The Domain Name System is specified in [RFC1034] and [RFC1035] and
many later RFCs, which have never been consolidated. It is one of
the most important infrastructure components of the Internet and
often ignored or misunderstood by Internet users (and even by many
professionals). Almost every activity on the Internet starts with a
DNS query (and often several). Its use has many privacy implications
and this is an attempt at a comprehensive and accurate list.
Let us begin with a simplified reminder of how the DNS works. (See
also [I-D.ietf-dnsop-dns-terminology].) A client, the stub resolver,
issues a DNS query to a server, called the recursive resolver (also
called caching resolver or full resolver or recursive name server).
Let's use the query "What are the AAAA records for www.example.com?"
as an example. AAAA is the QTYPE (Query Type), and www.example.com
is the QNAME (Query Name). (The description which follows assumes a
cold cache, for instance because the server just started.) The
recursive resolver will first query the root nameservers. In most
cases, the root nameservers will send a referral. In this example,
the referral will be to the .com nameservers. The resolver repeats
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the query to one of the .com nameservers. The .com nameservers, in
turn, will refer to the example.com nameservers. The example.com
nameserver will then return the answer. The root name servers, the
name servers of .com and the name servers of example.com are called
authoritative name servers. It is important, when analyzing the
privacy issues, to remember that the question asked to all these name
servers is always the original question, not a derived question. The
question sent to the root name servers is "What are the AAAA records
for www.example.com?", not "What are the name servers of .com?". By
repeating the full question, instead of just the relevant part of the
question to the next in line, the DNS provides more information than
necessary to the nameserver.
Because DNS relies on caching heavily, the algorithm described just
above is actually a bit more complicated, and not all questions are
sent to the authoritative name servers. If a few seconds later the
stub resolver asks to the recursive resolver, "What are the SRV
records of _xmpp-server._tcp.example.com?", the recursive resolver
will remember that it knows the name servers of example.com and will
just query them, bypassing the root and .com. Because there is
typically no caching in the stub resolver, the recursive resolver,
unlike the authoritative servers, sees all the DNS traffic.
(Applications, like Web browsers, may have some form of caching which
do not follow DNS rules, for instance because it may ignore the TTL.
So, the recursive resolver does not see all the name resolution
activity.)
It should be noted that DNS recursive resolvers sometimes forward
requests to other recursive resolvers, typically bigger machines,
with a larger and more shared cache (and the query hierarchy can be
even deeper, with more than two levels of recursive resolvers). From
the point of view of privacy, these forwarders are like resolvers,
except that they do not see all of the requests being made (due to
caching in the first resolver).
Almost all this DNS traffic is currently sent in clear (unencrypted).
There are a few cases where there is some channel encryption, for
instance in an IPsec VPN, at least between the stub resolver and the
resolver.
Today, almost all DNS queries are sent over UDP [thomas-ditl-tcp].
This has practical consequences when considering encryption of the
traffic as a possible privacy technique. Some encryption solutions
are only designed for TCP, not UDP.
Another important point to keep in mind when analyzing the privacy
issues of DNS is the fact that DNS requests received by a server were
triggered by different reasons. Let's assume an eavesdropper wants
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to know which Web page is viewed by a user. For a typical Web page,
there are three sorts of DNS requests being issued:
Primary request: this is the domain name in the URL that the user
typed, selected from a bookmark or chose by clicking on an
hyperlink. Presumably, this is what is of interest for the
eavesdropper.
Secondary requests: these are the additional requests performed by
the user agent (here, the Web browser) without any direct
involvement or knowledge of the user. For the Web, they are
triggered by embedded content, CSS sheets, JavaScript code,
embedded images, etc. In some cases, there can be dozens of
domain names in different contexts on a single Web page.
Tertiary requests: these are the additional requests performed by
the DNS system itself. For instance, if the answer to a query is
a referral to a set of name servers, and the glue records are not
returned, the resolver will have to do additional requests to turn
name servers' names into IP addresses. Similarly, even if glue
records are returned, a careful recursive server will do tertiary
requests to verify the IP addresses of those records.
It can be noted also that, in the case of a typical Web browser, more
DNS requests than stricly necessary are sent, for instance to
prefetch resources that the user may query later, or when
autocompleting the URL in the address bar. Both are a big privacy
concern since they may leak information even about non-explicit
actions. For instance, just reading a local HTML page, even without
selecting the hyperlinks, may trigger DNS requests.
For privacy-related terms, we will use here the terminology of
[RFC6973].
2. Risks
This document focuses mostly on the study of privacy risks for the
end-user (the one performing DNS requests). We consider the risks of
pervasive surveillance ([RFC7258]) as well as risks coming from a
more focused surveillance. Privacy risks for the holder of a zone
(the risk that someone gets the data) are discussed in [RFC5936] and
[RFC5155]. Non-privacy risks (such as cache poisoning) are out of
scope.
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2.1. The alleged public nature of DNS data
It has long been claimed that "the data in the DNS is public". While
this sentence makes sense for an Internet-wide lookup system, there
are multiple facets to the data and metadata involved that deserve a
more detailed look. First, access control lists and private
namespaces nonwithstanding, the DNS operates under the assumption
that public facing authoritative name servers will respond to "usual"
DNS queries for any zone they are authoritative for without further
authentication or authorization of the client (resolver). Due to the
lack of search capabilities, only a given QNAME will reveal the
resource records associated with that name (or that name's non-
existence). In other words: one needs to know what to ask for, in
order to receive a response. The zone transfer QTYPE [RFC5936] is
often blocked or restricted to authenticated/authorized access to
enforce this difference (and maybe for other reasons).
Another differentiation to be considered is between the DNS data
itself and a particular transaction (i.e., a DNS name lookup). DNS
data and the results of a DNS query are public, within the boundaries
described above, and may not have any confidentiality requirements.
However, the same is not true of a single transaction or sequence of
transactions; that transaction is not/should not be public. A
typical example from outside the DNS world is: the Web site of
Alcoholics Anonymous is public; the fact that you visit it should not
be.
2.2. Data in the DNS request
The DNS request includes many fields but two of them seem
particularly relevant for the privacy issues: the QNAME and the
source IP address. "source IP address" is used in a loose sense of
"source IP address + maybe source port", because the port is also in
the request and can be used to differentiate between several users
sharing an IP address (behind a CGN for instance [RFC6269]).
The QNAME is the full name sent by the user. It gives information
about what the user does ("What are the MX records of example.net?"
means he probably wants to send email to someone at example.net,
which may be a domain used by only a few persons and therefore very
revealing about communication relationships). Some QNAMEs are more
sensitive than others. For instance, querying the A record of a
well-known Web statistics domain reveals very little (everybody
visits Web sites which use this analytics service) but querying the A
record of www.verybad.example where verybad.example is the domain of
an organization that some people find offensive or objectionable, may
create more problems for the user. Also, sometimes, the QNAME embeds
the software one uses, which could be a privacy issue. For instance,
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_ldap._tcp.Default-First-Site-Name._sites.gc._msdcs.example.org.
There are also some BitTorrent clients that query a SRV record for
_bittorrent-tracker._tcp.domain.example.
Another important thing about the privacy of the QNAME is the future
usages. Today, the lack of privacy is an obstacle to putting
potentially sensitive or personally identifiable data in the DNS. At
the moment your DNS traffic might reveal that you are doing email but
not with whom. If your MUA starts looking up PGP keys in the DNS
[I-D.wouters-dane-openpgp] then privacy becomes a lot more important.
And email is just an example; there would be other really interesting
uses for a more privacy-friendly DNS.
For the communication between the stub resolver and the recursive
resolver, the source IP address is the address of the user's machine.
Therefore, all the issues and warnings about collection of IP
addresses apply here. For the communication between the recursive
resolver and the authoritative name servers, the source IP address
has a different meaning; it does not have the same status as the
source address in a HTTP connection. It is now the IP address of the
recursive resolver which, in a way "hides" the real user. However,
hiding does not always work. Sometimes
[I-D.ietf-dnsop-edns-client-subnet] is used (see its privacy analysis
in [denis-edns-client-subnet]). Sometimes the end user has a
personal recursive resolver on her machine. In both cases, the IP
address is as sensitive as it is for HTTP [sidn-entrada].
A note about IP addresses: there is currently no IETF document which
describes in detail all the privacy issues around IP addressing. In
the meantime, the discussion here is intended to include both IPv4
and IPv6 source addresses. For a number of reasons their assignment
and utilization characteristics are different, which may have
implications for details of information leakage associated with the
collection of source addresses. (For example, a specific IPv6 source
address seen on the public Internet is less likely than an IPv4
address to originate behind a CGN or other NAT.) However, for both
IPv4 and IPv6 addresses, it's important to note that source addresses
are propagated with queries and comprise metadata about the host,
user, or application that originated them.
2.3. Cache snooping
The content of recursive resolvers' caches can reveal data about the
clients using it (the privacy risks depend on the number of clients).
This information can sometimes be examined by sending DNS queries
with RD=0 to inspect cache content, particularly looking at the DNS
TTLs [grangeia.snooping]. Since this also is a reconnaissance
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technique for subsequent cache poisoning attacks, some counter
measures have already been developed and deployed.
2.4. On the wire
DNS traffic can be seen by an eavesdropper like any other traffic.
It is typically not encrypted. (DNSSEC, specified in [RFC4033]
explicitly excludes confidentiality from its goals.) So, if an
initiator starts a HTTPS communication with a recipient, while the
HTTP traffic will be encrypted, the DNS exchange prior to it will not
be. When other protocols will become more and more privacy-aware and
secured against surveillance, the DNS may become "the weakest link"
in privacy.
An important specificity of the DNS traffic is that it may take a
different path than the communication between the initiator and the
recipient. For instance, an eavesdropper may be unable to tap the
wire between the initiator and the recipient but may have access to
the wire going to the recursive resolver, or to the authoritative
name servers.
The best place to tap, from an eavesdropper's point of view, is
clearly between the stub resolvers and the recursive resolvers,
because traffic is not limited by DNS caching.
The attack surface between the stub resolver and the rest of the
world can vary widely depending upon how the end user's computer is
configured. By order of increasing attack surface:
The recursive resolver can be on the end user's computer. In
(currently) a small number of cases, individuals may choose to
operate their own DNS resolver on their local machine. In this
case the attack surface for the connection between the stub
resolver and the caching resolver is limited to that single
machine.
The recursive resolver may be at the local network edge. For
many/most enterprise networks and for some residential users the
caching resolver may exist on a server at the edge of the local
network. In this case the attack surface is the local network.
Note that in large enterprise networks the DNS resolver may not be
located at the edge of the local network but rather at the edge of
the overall enterprise network. In this case the enterprise
network could be thought of as similar to the IAP (Internet Access
Provider) network referenced below.
The recursive resolver can be in the IAP (Internet Access
Provider) premises. For most residential users and potentially
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other networks the typical case is for the end user's computer to
be configured (typically automatically through DHCP) with the
addresses of the DNS recursive resolvers at the IAP. The attack
surface for on-the-wire attacks is therefore from the end user
system across the local network and across the IAP network to the
IAP's recursive resolvers.
The recursive resolver can be a public DNS service. Some machines
may be configured to use public DNS resolvers such as those
operated today by Google Public DNS or OpenDNS. The end user may
have configured their machine to use these DNS recursive resolvers
themselves - or their IAP may have chosen to use the public DNS
resolvers rather than operating their own resolvers. In this case
the attack surface is the entire public Internet between the end
user's connection and the public DNS service.
2.5. In the servers
Using the terminology of [RFC6973], the DNS servers (recursive
resolvers and authoritative servers) are enablers: they facilitate
communication between an initiator and a recipient without being
directly in the communications path. As a result, they are often
forgotten in risk analysis. But, to quote again [RFC6973], "Although
[...] enablers may not generally be considered as attackers, they may
all pose privacy threats (depending on the context) because they are
able to observe, collect, process, and transfer privacy-relevant
data." In [RFC6973] parlance, enablers become observers when they
start collecting data.
Many programs exist to collect and analyze DNS data at the servers.
From the "query log" of some programs like BIND, to tcpdump and more
sophisticated programs like PacketQ [packetq] and DNSmezzo
[dnsmezzo]. The organization managing the DNS server can use these
data itself or it can be part of a surveillance program like PRISM
[prism] and pass data to an outside observer.
Sometimes, these data are kept for a long time and/or distributed to
third parties, for research purposes [ditl] [day-at-root], for
security analysis, or for surveillance tasks. These uses are
sometimes under some sort of contract, with various limitations, for
instance on redistribution, giving the sensitive nature of the data.
Also, there are observation points in the network which gather DNS
data and then make it accessible to third-parties for research or
security purposes ("passive DNS [passive-dns]").
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2.5.1. In the recursive resolvers
Recursive Resolvers see all the traffic since there is typically no
caching before them. To summarize: your recursive resolver knows a
lot about you. The resolver of a large IAP, or a large public
resolver can collect data from many users. You may get an idea of
the data collected by reading the privacy policy of a big public
resolver [1].
2.5.2. In the authoritative name servers
Unlike what happens for recursive resolvers, observation capabilities
of authoritative name servers are limited by caching; they see only
the requests for which the answer was not in the cache. For
aggregated statistics ("What is the percentage of LOC queries?"),
this is sufficient; but it prevents an observer from seeing
everything. Still, the authoritative name servers see a part of the
traffic, and this subset may be sufficient to violate some privacy
expectations.
Also, the end user has typically some legal/contractual link with the
recursive resolver (he has chosen the IAP, or he has chosen to use a
given public resolver), while having no control and perhaps no
awareness of the role of the authoritative name servers and their
observation abilities.
As noted before, using a local resolver or a resolver close to the
machine decreases the attack surface for an on-the-wire eavesdropper.
But it may decrease privacy against an observer located on an
authoritative name server. This authoritative name server will see
the IP address of the end client, instead of the address of a big
recursive resolver shared by many users.
This "protection", when using a large resolver with many clients, is
no longer present if [I-D.ietf-dnsop-edns-client-subnet] is used
because, in this case, the authoritative name server sees the
original IP address (or prefix, depending on the setup).
As of today, all the instances of one root name server, L-root,
receive together around 50,000 queries per second. While most of it
is "junk" (errors on the TLD name), it gives an idea of the amount of
big data which pours into name servers. (And even "junk" can leak
information, for instance if there is a typing error in the TLD, the
user will send data to a TLD which is not the usual one.)
Many domains, including TLDs, are partially hosted by third-party
servers, sometimes in a different country. The contracts between the
domain manager and these servers may or may not take privacy into
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account. Whatever the contract, the third-party hoster may be honest
or not but, in any case, it will have to follow its local laws. So,
requests to a given ccTLD may go to servers managed by organizations
outside of the ccTLD's country. End-users may not anticipate that,
when doing a security analysis.
Also, it seems [aeris-dns] that there is a strong concentration of
authoritative name servers among "popular" domains (such as the Alexa
Top N list). For instance, among the Alexa Top 100k, one DNS
provider hosts today 10 % of the domains. The ten most important DNS
providers host together one third of the domains. With the control
(or the ability to sniff the traffic) of a few name servers, you can
gather a lot of information.
2.5.3. Rogue servers
The previous paragraphs discussed DNS privacy, assuming that all the
traffic was directed to the intended servers, and that the potential
attacker was purely passive. But, in reality, we can have active
attackers, redirecting the traffic, not for changing it but just to
observe it.
For instance, a rogue DHCP server, or a trusted DHCP server that has
had its configuration altered by malicious parties, can direct you to
a rogue recursive resolver. Most of the time, it seems to be done to
divert traffic, by providing lies for some domain names. But it
could be used just to capture the traffic and gather information
about you. Other attacks, besides using DHCP, are possible. The
traffic from a DNS client to a DNS server can be intercepted along
its way from originator to intended source; for instance by
transparent DNS proxies in the network that will divert the traffic
intended for a legitimate DNS server. This rogue server can
masquerade as the intended server and respond with data to the
client. (Rogue servers that inject malicious data are possible, but
is a separate problem not relevant to privacy.) A rogue server may
respond correctly for a long period of time, thereby foregoing
detection. This may be done for what could be claimed to be good
reasons, such as optimization or caching, but it leads to a reduction
of privacy compared to if there were no attacker present. Also,
malware like DNSchanger [dnschanger] can change the recursive
resolver in the machine's configuration, or the routing itself can be
subverted (for instance [turkey-googledns]).
A practical consequence of this section is that solutions for DNS
privacy may have to address authentication of the server, not just
passive sniffing.
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2.6. Re-identification and other inferences
An observer has access not only to the data he/she directly collects
but also to the results of various inferences about these data.
For instance, a user can be re-identified via DNS queries. If the
adversary knows a user's identity and can watch their DNS queries for
a period, then that same adversary may be able to re-identify the
user solely based on their pattern of DNS queries later on regardless
of the location from which the user makes those queries. For
example, one study [herrmann-reidentification] found that such re-
identification is possible so that "73.1% of all day-to-day links
were correctly established, i.e. user u was either re-identified
unambiguously (1) or the classifier correctly reported that u was not
present on day t+1 any more (2)". While that study related to web
browsing behaviour, equally characteristic patterns may be produced
even in machine-to-machine communications or without a user taking
specific actions, e.g. at reboot time if a characteristic set of
services are accessed by the device.
For instance, one could imagine, for an intelligence agency to
identify people going to a site by putting in a very long DNS name
and looking for queries of a specific length. Such traffic analysis
could weaken some privacy solutions.
The IAB privacy and security programme also have a work in progress
[I-D.iab-privsec-confidentiality-threat] that considers such
inference based attacks in a more general framework.
3. Actual "attacks"
A very quick examination of DNS traffic may lead to the false
conclusion that extracting the needle from the haystack is difficult.
"Interesting" primary DNS requests are mixed with useless (for the
eavesdropper) secondary and tertiary requests (see the terminology in
Section 1). But, in this time of "big data" processing, powerful
techniques now exist to get from the raw data to what the
eavesdropper is actually interested in.
Many research papers about malware detection use DNS traffic to
detect "abnormal" behaviour that can be traced back to the activity
of malware on infected machines. Yes, this research was done for the
good; but, technically, it is a privacy attack and it demonstrates
the power of the observation of DNS traffic. See [dns-footprint],
[dagon-malware] and [darkreading-dns].
Passive DNS systems [passive-dns] allow reconstruction of the data of
sometimes an entire zone. They are used for many reasons, some good,
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some bad. Well-known passive DNS systems keep only the DNS
responses, and not the source IP address of the client, precisely for
privacy reasons. Other passive DNS systems may not be so careful.
And there is still the potential problems with revealing QNAMEs.
The revelations (from the Edward Snowden documents, leaked from the
NSA) of the MORECOWBELL surveillance program [morecowbell], which
uses the DNS, both passively and actively, to surreptitiously gather
information about the users, is another good example showing that the
lack of privacy protections in the DNS is actively exploited.
4. Legalities
To our knowledge, there are no specific privacy laws for DNS data, in
any country. Interpreting general privacy laws like
[data-protection-directive] (European Union) in the context of DNS
traffic data is not an easy task and we do not know a court precedent
here. An interesting analysis is [sidn-entrada].
5. Security considerations
This document is entirely about security, more precisely privacy. It
just lays out the problem, it does not try to set requirements (with
the choices and compromises they imply), much less to define
solutions. Possible solutions to the issues described here are
discussed in other documents (currently too many to all be
mentioned), see for instance [I-D.ietf-dnsop-qname-minimisation] for
the minimisation of data, or [I-D.ietf-dprive-start-tls-for-dns]
about encryption.
6. Acknowledgments
Thanks to Nathalie Boulvard and to the CENTR members for the original
work which leaded to this document. Thanks to Ondrej Sury for the
interesting discussions. Thanks to Mohsen Souissi and John Heidemann
for proofreading, to Paul Hoffman, Matthijs Mekking, Marcos Sanz, Tim
Wicinski, Francis Dupont, Allison Mankin and Warren Kumari for
proofreading, technical remarks, and many readability improvements.
Thanks to Dan York, Suzanne Woolf, Tony Finch, Stephen Farrell, Peter
Koch, Simon Josefsson and Frank Denis for good written contributions.
And thanks to the IESG members for the last remarks.
7. IANA considerations
This document has no actions for IANA.
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8. References
8.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[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.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, May 2014.
8.2. Informative References
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements", RFC
4033, March 2005.
[RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
Security (DNSSEC) Hashed Authenticated Denial of
Existence", RFC 5155, March 2008.
[RFC5936] Lewis, E. and A. Hoenes, "DNS Zone Transfer Protocol
(AXFR)", RFC 5936, June 2010.
[RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
Roberts, "Issues with IP Address Sharing", RFC 6269, June
2011.
[I-D.ietf-dnsop-edns-client-subnet]
Contavalli, C., Gaast, W., Lawrence, D., and W. Kumari,
"Client Subnet in DNS Querys", draft-ietf-dnsop-edns-
client-subnet-01 (work in progress), May 2015.
[I-D.iab-privsec-confidentiality-threat]
Barnes, R., Schneier, B., Jennings, C., Hardie, T.,
Trammell, B., Huitema, C., and D. Borkmann,
"Confidentiality in the Face of Pervasive Surveillance: A
Threat Model and Problem Statement", draft-iab-privsec-
confidentiality-threat-07 (work in progress), May 2015.
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[I-D.wouters-dane-openpgp]
Wouters, P., "Using DANE to Associate OpenPGP public keys
with email addresses", draft-wouters-dane-openpgp-02 (work
in progress), February 2014.
[I-D.ietf-dprive-start-tls-for-dns]
Zi, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
and P. Hoffman, "TLS for DNS: Initiation and Performance
Considerations", draft-ietf-dprive-start-tls-for-dns-00
(work in progress), May 2015.
[I-D.ietf-dnsop-qname-minimisation]
Bortzmeyer, S., "DNS query name minimisation to improve
privacy", draft-ietf-dnsop-qname-minimisation-03 (work in
progress), June 2015.
[I-D.ietf-dnsop-dns-terminology]
Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", draft-ietf-dnsop-dns-terminology-02 (work in
progress), May 2015.
[denis-edns-client-subnet]
Denis, F., "Security and privacy issues of edns-client-
subnet", August 2013, <https://00f.net/2013/08/07/edns-
client-subnet/>.
[dagon-malware]
Dagon, D., "Corrupted DNS Resolution Paths: The Rise of a
Malicious Resolution Authority", 2007, <https://www.dns-
oarc.net/files/workshop-2007/Dagon-Resolution-
corruption.pdf>.
[dns-footprint]
Stoner, E., "DNS footprint of malware", October 2010,
<https://www.dns-oarc.net/files/workshop-201010/OARC-ers-
20101012.pdf>.
[morecowbell]
Grothoff, C., Wachs, M., Ermert, M., and J. Appelbaum,
"NSA's MORECOWBELL: Knell for DNS", January 2015,
<https://gnunet.org/morecowbell>.
[darkreading-dns]
Lemos, R., "Got Malware? Three Signs Revealed In DNS
Traffic", May 2013,
<http://www.darkreading.com/monitoring/
got-malware-three-signs-revealed-in-dns/240154181>.
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[dnschanger]
Wikipedia, , "DNSchanger", November 2011,
<http://en.wikipedia.org/wiki/DNSChanger>.
[packetq] Dot SE, , "PacketQ, a simple tool to make SQL-queries
against PCAP-files", 2011,
<https://github.com/dotse/packetq/wiki>.
[dnsmezzo]
Bortzmeyer, S., "DNSmezzo", 2009,
<http://www.dnsmezzo.net/>.
[prism] NSA, , "PRISM", 2007, <http://en.wikipedia.org/wiki/
PRISM_%28surveillance_program%29>.
[grangeia.snooping]
Grangeia, L., "DNS Cache Snooping or Snooping the Cache
for Fun and Profit", 2004,
<http://www.msit2005.mut.ac.th/msit_media/1_2551/nete4630/
materials/20080718130017Hc.pdf>.
[ditl] CAIDA, , "A Day in the Life of the Internet (DITL)", 2002,
<http://www.caida.org/projects/ditl/>.
[day-at-root]
Castro, S., Wessels, D., Fomenkov, M., and K. Claffy, "A
Day at the Root of the Internet", 2008,
<http://www.sigcomm.org/sites/default/files/ccr/
papers/2008/October/1452335-1452341.pdf>.
[turkey-googledns]
Bortzmeyer, S., "Hijacking of public DNS servers in
Turkey, through routing", 2014,
<http://www.bortzmeyer.org/
dns-routing-hijack-turkey.html>.
[data-protection-directive]
Europe, , "European directive 95/46/EC on the protection
of individuals with regard to the processing of personal
data and on the free movement of such data", November
1995, <http://eur-lex.europa.eu/LexUriServ/
LexUriServ.do?uri=CELEX:31995L0046:EN:HTML>.
[passive-dns]
Weimer, F., "Passive DNS Replication", April 2005,
<http://www.enyo.de/fw/software/dnslogger/#2>.
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[tor-leak]
Tor, , "DNS leaks in Tor", 2013,
<https://trac.torproject.org/projects/tor/wiki/doc/TorFAQ#
IkeepseeingthesewarningsaboutSOCKSandDNSandinformationleak
s.ShouldIworry>.
[yanbin-tsudik]
Yanbin, L. and G. Tsudik, "Towards Plugging Privacy Leaks
in the Domain Name System", 2009,
<http://arxiv.org/abs/0910.2472>.
[castillo-garcia]
Castillo-Perez, S. and J. Garcia-Alfaro, "Anonymous
Resolution of DNS Queries", 2008,
<http://deic.uab.es/~joaquin/papers/is08.pdf>.
[fangming-hori-sakurai]
Fangming, , Hori, Y., and K. Sakurai, "Analysis of Privacy
Disclosure in DNS Query", 2007,
<http://dl.acm.org/citation.cfm?id=1262690.1262986>.
[thomas-ditl-tcp]
Thomas, M. and D. Wessels, "An Analysis of TCP Traffic in
Root Server DITL Data"", 2014, <https://indico.dns-
oarc.net/event/20/session/2/contribution/15/material/
slides/1.pdf>.
[federrath-fuchs-herrmann-piosecny]
Federrath, H., Fuchs, K., Herrmann, D., and C. Piosecny,
"Privacy-Preserving DNS: Analysis of Broadcast, Range
Queries and Mix-Based Protection Methods", 2011,
<https://svs.informatik.uni-hamburg.de/publications/2011/2
011-09-14_FFHP_PrivacyPreservingDNS_ESORICS2011.pdf>.
[aeris-dns]
Vinot, N., "[In French] Vie privee : et le DNS alors ?",
2015, <https://blog.imirhil.fr/vie-privee-et-le-dns-
alors.html>.
[herrmann-reidentification]
Herrmann, D., Gerber, C., Banse, C., and H. Federrath,
"Analyzing characteristic host access patterns for re-
identification of web user sessions", 2012,
<http://epub.uni-regensburg.de/21103/1/
Paper_PUL_nordsec_published.pdf>.
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[sidn-entrada]
Hesselman, C., Jansen, J., Wullink, M., Vink, K., and M.
Simon, "A privacy framework for 'DNS big data'
applications", 2014,
<https://www.sidnlabs.nl/uploads/tx_sidnpublications/
SIDN_Labs_Privacyraamwerk_Position_Paper_V1.4_ENG.pdf>.
8.3. URIs
[1] https://developers.google.com/speed/public-dns/privacy
Author's Address
Stephane Bortzmeyer
AFNIC
1, rue Stephenson
Montigny-le-Bretonneux 78180
France
Phone: +33 1 39 30 83 46
Email: bortzmeyer+ietf@nic.fr
URI: http://www.afnic.fr/
Bortzmeyer Expires December 17, 2015 [Page 17]
