pdns-qof/i-d/pdns-qof.txt
Aaron Kaplan 0759138dc8 re-formatted xml
described the three potential output formats
be more specific with field descriptions
minor corrections
2013-02-05 19:28:27 +01:00

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Internet Engineering Task Force Dulaunoy
Internet-Draft CIRCL
Intended status: Informational Kaplan
Expires: July 5, 2013 CERT.at
January 2013
Passive DNS - Common Output Format
draft-ietf-dulaunoy-kaplan-pdns-cof-01
Abstract
This document describes the output format used between Passive DNS
query interface. The output format description includes also a
common meaning per Passive DNS system.
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of 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 5, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Limitation . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Output Format . . . . . . . . . . . . . . . . . . . . . . 4
3.1.1. Whois Human Readable . . . . . . . . . . . . . . . . . 4
3.1.2. JSON . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.3. Bind format . . . . . . . . . . . . . . . . . . . . . 5
4. Mandatory Fields . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. rrname . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. rrtype . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.3. rdata . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.4. time_first . . . . . . . . . . . . . . . . . . . . . . . . 6
4.5. time_last . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Optional Fields . . . . . . . . . . . . . . . . . . . . . . . 6
5.1. sensor_id . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. count . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.3. ttl . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.4. bailiwick . . . . . . . . . . . . . . . . . . . . . . . . 6
5.5. class . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Extended Fields . . . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9. Security Considerations . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . . 7
10.2. Informative References . . . . . . . . . . . . . . . . . . 8
Appendix A. Additional Stuff . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . . . . 10
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1. Introduction
Passive DNS is a technique described by Florian Weimer in 2005 in
Passive DNS replication, F Weimer - 17th Annual FIRST Conference on
Computer Security. Since then multiple Passive DNS implementations
evolved over time. Users of these Passive DNS servers query a server
(often via Whois [Ref: WHOIS]), parse the results and process them in
other applications.
There are multiple implementation of Passive DNS software. Users of
passive DNS query each implementation and aggregate the results for
their search. This document describes the output format of three
Passive DNS Systems which are in use today and which already share a
nearly identical output format. As the format and the meaning of
output fields from each Passive DNS need to be consistent, we propose
in this document a solution to commonly name each field along with
their corresponding interpretation. The format format is following a
simple key-value structure. The benefit of having a consistent
Passive DNS output format is that multiple client implementations can
query different servers without having to have a separate parser for
each individual server.
[http://code.google.com/p/passive-dns-query-tool/] currently
implements multiple parsers due to a lack of standardization. The
document does not describe the protocol (e.g. whois, HTTP REST or
XMPP) used to query the Passive DNS.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Limitation
As a Passive DNS can include protection mechanisms for their
operation, results might be different due to those protection
measures. These mechanisms filter out DNS answers if they fail some
criteria. The bailiwick algorithm (c.f.
http://www.isc.org/files/passive_dns_hardening_handout.pdf) protects
the Passive DNS Database from cache poisoning attacks [ref: Dan
Kaminsky]. Another limitiation that clients querying the database
need to be aware of is that each query simply gets an snapshot-answer
of the time of querying. Clients MUST NOT rely on consistent
answers.
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3. Format
A field is composed a key followed by a value separated by the single
':' character and a space before the value. The format is based on
the initial work done by Florian Weimer and the RIPE whois format
(ref:http://www.enyo.de/fw/software/dnslogger/whois.html). The order
of the fields is not significant for the same resource type. That
measn, the same name tuple plus timing information identifies a
unique answer per server.
A sample output using the common format:
rrname: www.foo.be
rrtype: AAAA
rdata: 2001:6f8:202:2df::2
time_first: 2010-07-26 13:04:01
time_last: 2012-02-06 09:59:00
count: 87
3.1. Output Format
Depending on the clients request, there might be one of three
different answers from the server: Whois (human readable) output
format (key-value), JSON [RFC4627] output and optionally Bind zone
file output format. XXX FIXME: how does the client select which
answer format he wants? XXX
3.1.1. Whois Human Readable
This output format originates with the original design of BFK's
passive DNS server implementation. The intent is to be be human
readable. Every implementation MUST support the Whois human readable
format.
A sample output using the Whois format:
rrname: www.foo.be
rrtype: AAAA
rdata: 2001:6f8:202:2df::2
time_first: 2010-07-26 13:04:01
time_last: 2012-02-06 09:59:00
count: 87
3.1.2. JSON
The intent of this output format is to be easily parseable by
scripts. Every implementation SHOULD support the JSON output format.
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A sample output using the JSON format:
... (list of )...
{ "count": 97167,
"time_first": "2010-06-25 17:07:02",
"rrtype": "A", "rrname": "google-public-dns-a.google.com.",
"rdata": "8.8.8.8",
"time_last": "2013-02-05 17:34:03" }
... (separated by newline)...
3.1.3. Bind format
A sample output using the Bind format:
google-public-dns-a.google.com. IN A 8.8.8.8
4. Mandatory Fields
Implementation MUST support all the mandatory fields.
The tuple (rrtype,rrname,rdata) will always be unique within one
answer per server.
4.1. rrname
This field returns the name of the queried resource.
4.2. rrtype
This field returns the resource record type as seen by the passive
DNS. The key is rrtype and the value is in the interpreted record
type. If the value cannot be interpreted the decimal value is
returned. The resource record type can be any values as described by
IANA in the DNS parameters document in the section 'DNS Label types'
(http://www.iana.org/assignments/dns-parameters). Currently known
and supported textual descritptions of rrtypes are: A, AAAA, CNAME,
PTR, SOA, TXT, DNAME, NS, SRV, RP, NAPTR, HINFO, A6 A client MUST be
able to understand these textual rtype values. In addition, a client
MUST be able to handle a decimal value (as mentioned above) as
answer.
4.3. rdata
This field returns the data of the queried resource. In general,
this is to be interpreted as string. Depending on the rtype, this
can be an IPv4 or IPv6 address, a domain name (as in the case of
CNAMEs), an SPF record, etc. A client MUST be able to interpret any
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value which is legal as the right hand side in a DNS zone file RFC
1035 [RFC1035] and RFC 1034 [RFC1034].
4.4. time_first
This field returns the first time that the record / unique tuple
(rrname, rrtype, rdata) has been seen by the passive DNS. The date
is expressed in ISO 8601 and UTC.
4.5. time_last
This field returns the last time that the unique tuple (rrname,
rrtype, rdata) record has been seen by the passive DNS. The date is
expressed in ISO 8601 and UTC.
5. Optional Fields
Implementation SHOULD support one or more field.
5.1. sensor_id
This field returns the sensor information where the record was seen.
The sensor_id is expressed in a decimal value.
5.2. count
Specifies how many authoritative answers were received with the set
of answers (i.e. same data) over all sensors. The number of requests
is expressed as a decimal value.
5.3. ttl
the TTL as specified in RFC 1035 [RFC1035] as a decimal value.
5.4. bailiwick
XXX FIXME: input from ISC needed
5.5. class
the class as specified in RFC 1035 [RFC1035]. Valid values are IN,
HS (for HESIOD), CH (for CHAOS). May be omitted, the default
assumption that a client should make is IN.
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6. Extended Fields
An x- prefixed key means that is an extension and a non-standard
field defined by the implementation of the passive DNS.
7. Acknowledgements
Thanks to the Passive DNS developers who contributed to the document.
8. IANA Considerations
This memo includes no request to IANA.
9. Security Considerations
In some cases, Passive DNS output might contain confidential
information and its access might be restricted. When an user is
querying multiple Passive DNS and aggregating the data, the
sensitivity of the data must be considered.
Authentication and signing of the output MAY be implemented on the
server via an extended field, namely x-signature-sha265 which
contains a SHA256 signature of the output text, signed with the ssh-
key of the server sending the answer.
All drafts are required to have a security considerations section.
See RFC 3552 [RFC3552] for a guide.
10. References
10.1. 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.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006.
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[min_ref] authSurName, authInitials., "Minimal Reference", 2006.
10.2. Informative References
[DOMINATION]
Mad Dominators, Inc., "Ultimate Plan for Taking Over the
World", 1984, <http://www.example.com/dominator.html>.
[I-D.narten-iana-considerations-rfc2434bis]
Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs",
draft-narten-iana-considerations-rfc2434bis-09 (work in
progress), March 2008.
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552,
July 2003.
Appendix A. Additional Stuff
This becomes an Appendix.
Authors' Addresses
Alexandre Dulaunoy
CIRCL
41, avenue de la gare
Luxembourg, L-1611
LU
Phone: (+352) 247 88444
Email: alexandre.dulaunoy@circl.lu
URI: http://www.circl.lu/
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Leon Aaron Kaplan
CERT.at
Karlsplatz 1/2/9
Vienna, A-1010
AT
Phone: +43 1 5056416 78
Email: kaplan@cert.at
URI: http://www.cert.at/
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