pdns-qof/i-d/pdns-qof.txt

Internet Engineering Task Force                                 Dulaunoy
Internet-Draft                                                     CIRCL
Intended status: Informational                                    Kaplan
Expires: June 28, 2014                                           CERT.at
                                                                   Vixie
                                                 Farsight Security, Inc.
                                                               hs. Stern
                                                                   Cisco
                                                       December 25, 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

   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
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   This Internet-Draft will expire on June 28, 2014.

Copyright Notice

   Copyright (c) 2013 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
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   to this document.  Code Components extracted from this document must



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Limitation  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Common Output Format  . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Overview and Example  . . . . . . . . . . . . . . . . . .   3
     3.2.  Mandatory Fields  . . . . . . . . . . . . . . . . . . . .   4
       3.2.1.  rrname  . . . . . . . . . . . . . . . . . . . . . . .   4
       3.2.2.  rrtype  . . . . . . . . . . . . . . . . . . . . . . .   4
       3.2.3.  rdata . . . . . . . . . . . . . . . . . . . . . . . .   4
       3.2.4.  time_first  . . . . . . . . . . . . . . . . . . . . .   4
       3.2.5.  time_last . . . . . . . . . . . . . . . . . . . . . .   5
     3.3.  Optional Fields . . . . . . . . . . . . . . . . . . . . .   5
       3.3.1.  count . . . . . . . . . . . . . . . . . . . . . . . .   5
       3.3.2.  bailiwick . . . . . . . . . . . . . . . . . . . . . .   5
     3.4.  Additional Fields . . . . . . . . . . . . . . . . . . . .   5
       3.4.1.  sensor_id . . . . . . . . . . . . . . . . . . . . . .   5
       3.4.2.  zone_time_first . . . . . . . . . . . . . . . . . . .   5
       3.4.3.  zone_time_last  . . . . . . . . . . . . . . . . . . .   6
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  References  . . . . . . . . . . . . . . . . . . . . . . .   7
     7.3.  Informative References  . . . . . . . . . . . . . . . . .   7
   Appendix A.  Appendix . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

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 [RFC3912] or HTTP REST [REST]), 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



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   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 in JSON [RFC4627] format.  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. passivedns-client
   [PDNSCLIENT]currently implements multiple parsers due to a lack of
   standardization.  The document does not describe the protocol (e.g.
   WHOIS [RFC3912], HTTP REST [REST]) nor the query format used to query
   the Passive DNS.  Neither does this document describe "pre-recursor"
   Passive DNS Systems.

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 [BAILIWICK] protects the Passive
   DNS Database from cache poisoning attacks [CACHEPOISONING].  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.

3.  Common Output Format

   The formatting of the answer follows the JSON [RFC4627] format.  The
   order of the fields is not significant for the same resource type.
   That means, the same name tuple plus timing information identifies a
   unique answer per server.

3.1.  Overview and Example

   The intent of this output format is to be easily parseable by
   scripts.  Every implementation MUST support the JSON output format.

   A sample output using the JSON format:








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   ... (list of )...
   { "count": 97167,
   "time_first": "1277353744",
   "rrtype": "A", "rrname": "google-public-dns-a.google.com.",
   "rdata": "8.8.8.8",
   "time_last": "1386405372" }
   ... (separated by newline)...

3.2.  Mandatory Fields

   Implementation MUST support all the mandatory fields.

   The tuple (rrtype,rrname,rdata) will always be unique within one
   answer per server.

3.2.1.  rrname

   This field returns the name of the queried resource.

3.2.2.  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 following the principle of transparency as described in RFC
   3597 [RFC3597].  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.

3.2.3.  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
   value which is legal as the right hand side in a DNS zone file RFC
   1035 [RFC1035] and RFC 1034 [RFC1034].  If the rdata came from an
   unknown DNS resource records, the server must follow the transparency
   principle as described in RFC 3597 [RFC3597].

3.2.4.  time_first





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   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 seconds (decimal ascii) since 1st of January 1970
   (unix timestamp).  The time zone MUST be UTC.

3.2.5.  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 seconds (decimal ascii) since 1st of January 1970 (unix
   timestamp).  The time zone MUST be UTC.

3.3.  Optional Fields

   Implementation SHOULD support one or more field.

3.3.1.  count

   Specifies how many answers were received with the set of answers
   (i.e. same data).  The number of requests is expressed as a decimal
   value.

   Specifies the number of times this particular event denoted by the
   other type fields has been seen in the given time interval (between
   time_last and time_first).  Decimal number.

3.3.2.  bailiwick

   The bailiwick is the best estimate of the apex of the zone where this
   data is authoritative.  String.

3.4.  Additional Fields

   Implementations MAY support the following fields:

3.4.1.  sensor_id

   This field returns the sensor information where the record was seen.
   The sensor_id is an opaque byte string as defined by RFC 5001 in
   section 2.3 [RFC5001].

3.4.2.  zone_time_first

   This field returns the first time that the unique tuple (rrname,
   rrtype, rdata) record has been seen via zone file import.  The date
   is expressed in seconds (decimal ascii) since 1st of January 1970
   (unix timestamp).  The time zone MUST be UTC.




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3.4.3.  zone_time_last

   This field returns the last time that the unique tuple (rrname,
   rrtype, rdata) record has been seen via zone file import.  The date
   is expressed in seconds (decimal ascii) since 1st of January 1970
   (unix timestamp).  The time zone MUST be UTC.

4.  Acknowledgements

   Thanks to the Passive DNS developers who contributed to the document.

5.  IANA Considerations

   This memo includes no request to IANA.

6.  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.

7.  References

7.1.  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.

   [RFC3597]  Gustafsson, A., "Handling of Unknown DNS Resource Record
              (RR) Types", RFC 3597, September 2003.

   [RFC3912]  Daigle, L., "WHOIS Protocol Specification", RFC 3912,
              September 2004.

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627, July 2006.

   [RFC5001]  Austein, R., "DNS Name Server Identifier (NSID) Option",
              RFC 5001, August 2007.





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7.2.  References

   [BAILIWICK]
              "Passive DNS Hardening", 2010, <https://
              archive.farsightsecurity.com/Passive_DNS/
              passive_dns_hardening_handout.pdf>.

   [CACHEPOISONING]
              "Black ops 2008: It's the end of the cache as we know
              it.", 2008, <http://kurser.lobner.dk/dDist/DMK_BO2K8.pdf>.

   [PDNSCLIENT]
              "Queries 5 major Passive DNS databases: BFK, CERTEE,
              DNSParse, ISC, and VirusTotal.", 2013, <https://github.com
              /chrislee35/passivedns-client>.

   [REST]     "Representational State Transfer (REST)", 2000,
              <http://www.ics.uci.edu/~fielding/pubs/dissertation/
              rest_arch_style.htm>.

7.3.  Informative References

   [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.

   [RFC3912]  Daigle, L., "WHOIS Protocol Specification", RFC 3912,
              September 2004.

Appendix A.  Appendix

Authors' Addresses










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   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/


   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/


   Paul Vixie
   Farsight Security, Inc.

   Email: paul@redbarn.org
   URI:   /


   Henry Stern
   Cisco
   1741 Brunswick Street, Suite 500
   Halifax, Nova Scotia  B3J 3X8
   Canada

   Phone: +1 408 922 4555
   Email: hestern@cisco.com
   URI:   http://www.cisco.com/security













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