Passive DNS - Common Output Format
draft-dulaunoy-dnsop-passive-dns-cof-13

Domain Name System Operations                                A. Dulaunoy
Internet-Draft                                                     CIRCL
Intended status: Informational                                 A. Kaplan
Expires: 28 February 2025                                               
                                                                P. Vixie
                                                                H. Stern
                                                 Farsight Security, Inc.
                                                               W. Kumari
                                                                  Google
                                                          27 August 2024

                   Passive DNS - Common Output Format
                draft-dulaunoy-dnsop-passive-dns-cof-13

Abstract

   This document describes a common output format of Passive DNS servers
   that clients can query.  The output format description also includes
   a common semantic for each Passive DNS system.  By having multiple
   Passive DNS Systems adhere to the same output format for queries,
   users of multiple Passive DNS servers will be able to combine result
   sets easily.

Status of This Memo

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   This Internet-Draft will expire on 28 February 2025.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Limitations . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Common Output Format  . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  ABNF grammar  . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  Mandatory Fields  . . . . . . . . . . . . . . . . . . . .   5
       3.3.1.  rrname  . . . . . . . . . . . . . . . . . . . . . . .   6
       3.3.2.  rrtype  . . . . . . . . . . . . . . . . . . . . . . .   6
       3.3.3.  rdata . . . . . . . . . . . . . . . . . . . . . . . .   6
       3.3.4.  time_first  . . . . . . . . . . . . . . . . . . . . .   6
       3.3.5.  time_last . . . . . . . . . . . . . . . . . . . . . .   7
     3.4.  Optional Fields . . . . . . . . . . . . . . . . . . . . .   7
       3.4.1.  count . . . . . . . . . . . . . . . . . . . . . . . .   7
       3.4.2.  bailiwick . . . . . . . . . . . . . . . . . . . . . .   7
     3.5.  Additional Fields . . . . . . . . . . . . . . . . . . . .   7
       3.5.1.  sensor_id . . . . . . . . . . . . . . . . . . . . . .   7
       3.5.2.  zone_time_first . . . . . . . . . . . . . . . . . . .   7
       3.5.3.  zone_time_last  . . . . . . . . . . . . . . . . . . .   8
       3.5.4.  origin  . . . . . . . . . . . . . . . . . . . . . . .   8
       3.5.5.  time_first_ms . . . . . . . . . . . . . . . . . . . .   8
       3.5.6.  time_last_ms  . . . . . . . . . . . . . . . . . . . .   8
     3.6.  Additional Fields Registry  . . . . . . . . . . . . . . .   8
     3.7.  Additional notes  . . . . . . . . . . . . . . . . . . . .   8
     3.8.  Suggested MIME Types  . . . . . . . . . . . . . . . . . .   8
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .   9
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .  10
   9.  Informative References  . . . . . . . . . . . . . . . . . . .  11
   Appendix A.  Examples . . . . . . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

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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 [WEIMERPDNS].  It is a mechanism for logging DNS
   answers in a manner intended to minimize the privacy implications to
   users, and is widely by security researchers to investigate malware
   (for example to discover command and control servers), and other
   security threats.  By capturing only the "cache fill" DNS responses
   (responses from authoritative servers in response to queries
   performed by a recursive resolver when iteratively resolving a name),
   Passive DNS does not have access to the client (users) source IP,
   source port, destination IP, or destination port.

   As these answers are served in response to queries originally
   initiated by user devices, the Passive DNS data can be used to detect
   if devices using the resolver are connecting to known malicious
   domains, without identifying the individual users / devices.  In
   addition, as answers are responses to queries made by the recursive
   server itself, Passive DNS records the answers which are ultimately
   served to users.  This is important as authoritative servers may
   serve different answers to different query addresses, for example to
   increase performance (e.g Client Subnet in DNS Queries [RFC7871]) or
   to hide malicious behavior when queried from addresses known to be
   associated with security researchers.

   Passive DNS is usually implemented either by capturing DNS response
   packets themselves (i.e packets with a destination address of the
   recursive resolver, a source port of 53, and the QR bit set to 1) or
   by having the DNS software itself log these responses.  The latter
   method is likely to become more common as recursive to authoritative
   DNS communication becomes encrypted.

   Multiple Passive DNS implementations and services exist.  Users of
   these Passive DNS services may query a server (often via WHOIS
   [RFC3912] or HTTP REST [REST]), parse the results, and process them
   in other applications.  Users of Passive DNS query each
   implementation and aggregate the results for their search.  This
   document describes the output format of four Passive DNS Systems
   ([DNSDB], [DNSDBQ] , [PDNSCERTAT], [PDNSCIRCL] and [PDNSCOF]) that
   are in use today and that already share a nearly identical output
   format.  As the format and the meaning of output fields from each
   Passive DNS need to be consistent, this document proposes a solution
   to commonly name each field along with its corresponding
   interpretation.  The format follows 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

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   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.  Each of these are separate topics and deserve their own RFC
   documents.  This document describes the current best practices
   implemented in various Passive DNS server implementations.

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.  Limitations

   As Passive DNS servers 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.  Another limitation that
   clients querying the database need to be aware of is that each query
   simply gets a snapshot-in-time answer at the time of querying.
   Clients MUST NOT rely on existing answers from different Passive DNS
   database.  Nor should they assume that answers will be identical
   across multiple Passive DNS servers.

3.  Common Output Format

3.1.  Overview

   The formatting of the answer follows the JSON [RFC4627] format.  In
   fact, it is a subset of the full JSON language.  Notable differences
   are the modified definition of whitespace ("ws").  The order of the
   fields is not significant for the same resource type.

   The intent of this output format is to be easily parsable by scripts.
   Each JSON object is expressed on a single line to be processed by the
   client line-by-line.  Every implementation MUST support the JSON
   output format.

   Examples of JSON (Appendix A) output are in the appendix.

3.2.  ABNF grammar

   Formal grammar as defined in ABNF [RFC2234]

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   answer          = entries
   entries         = * ( entry newline )
   entry           = ws "{" ws keyvallist ws "}" ws
   keyvallist      = [ member *( value-separator member ) ]
   member          = field name-separator value
   name-separator  = ws %x3A ws            ; : colon
   value-separator = ws %x2C ws            ; , comma
   field           = field-name | futureField
   field-name      = "rrname" | "rrtype" | "rdata" | "time_first" |
                     "time_last" | "count" | "bailiwick" | "sensor_id" |
                     "zone_time_first" | "zone_time_last" | "origin" |
                     "time_first_ms" | "time_last_ms"
   futureField     = string
   newline         = [ CR ] LF
   CR              = %x0D                  ; Carrige return
   LF              = %x0A                  ; Line feed or New line
   qm              = %x22                  ; " Quotation mark
   ws              = *(
                       %x20 |              ; Space
                       %x09                ; Horizontal tab
                       )

                                  Figure 1

   Note that value is defined in JSON [RFC4627] and has the same
   specification as there.  The same goes for the definition of string.
   Note the changed definition of ws does not include CR or LF as those
   are NOT allowed in NDJSON, and thus the definition here MUST be used
   for other ABNF defitions in JSON [RFC4627] .

3.3.  Mandatory Fields

   Implementation MUST support all the mandatory fields.

   Uniqueness property: the tuple (rrname,rrtype,rdata) will always be
   unique within one answer per server.  While rrname and rrtype are
   always individual JSON primitive types (strings, numbers, booleans or
   null), rdata MAY return multiple resource records or a single record.
   When multiple resource records are returned, rdata MUST be a JSON
   array.  In the case of a single resource record is returned, rdata
   MUST be a JSON string or a JSON array containing one JSON string.
   Senders SHOULD send an array for rdata, but receivers MUST be able to
   accept a single-string result for rdata.

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3.3.1.  rrname

   This field returns the name of the queried resource.  Represented as
   a JSON [RFC4627] string.

3.3.2.  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 represented as a JSON [RFC4627] string.  If the value cannot be
   interpreted, the decimal value is returned, following the principle
   of transparency as described in RFC 3597 [RFC3597].  Then the decimal
   value is represented as a JSON [RFC4627] number.  The resource record
   type can be any values as described by IANA in the DNS parameters
   document in the section 'Resource Record (RR) TYPEs'
   (http://www.iana.org/assignments/dns-parameters).  Supported textual
   descriptions of rrtypes include: A, AAAA, CNAME, etc.  A client MUST
   be able to understand these textual rrtype values represented as a
   JSON [RFC4627] string.  In addition, a client MUST be able to handle
   a decimal value (as mentioned above) answer represented as a JSON
   [RFC4627] number.

3.3.3.  rdata

   This field returns the resource records of the queried resource.
   When multiple resource records are returned, rdata MUST be a JSON
   array containing JSON strings.  In the case of a single resource
   record being returned, rdata MUST be a JSON string or a JSON array
   containing one JSON string.  Each resource record is represented as a
   JSON [RFC4627] string.  Each resource record MUST be escaped as
   defined in section 2.6 of RFC4627 [RFC4627].  Depending on the
   rrtype, 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
   master 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] .

3.3.4.  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 seconds (decimal) since 1st of January 1970 (Unix
   timestamp).  The time zone MUST be UTC.  This field is represented as
   a JSON [RFC4627] number.

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3.3.5.  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) since 1st of January 1970 (Unix
   timestamp).  The time zone MUST be UTC.  This field is represented as
   a JSON [RFC4627] number.

3.4.  Optional Fields

   Implementations SHOULD support one or more fields.

3.4.1.  count

   Specifies how many authoritative DNS answers were received at the
   Passive DNS server's collectors with exactly the given set of values
   as answers (i.e. same data in the answer set - compare with the
   uniqueness property in "Mandatory Fields").  The number of requests
   is expressed as a decimal value.  This field is represented as a JSON
   [RFC4627] number.

3.4.2.  bailiwick

   The bailiwick is the best estimate of the apex of the zone where this
   data is authoritative.  This field is represented as a JSON [RFC4627]
   string.

3.5.  Additional Fields

   Implementations MAY support the following fields:

3.5.1.  sensor_id

   This field returns the sensor information where the record was seen.
   It is represented as a JSON [RFC4627] string.

   If the data originate from sensors or probes which are part of a
   publicly-known gathering or measurement system (e.g.  RIPE Atlas), a
   JSON [RFC4627] string SHOULD be prefixed.

3.5.2.  zone_time_first

   This field returns the first time that the unique tuple (rrname,
   rrtype, rdata) record has been seen via master file import.  The date
   is expressed in seconds (decimal) since 1st of January 1970 (Unix
   timestamp).  The time zone MUST be UTC.  This field is represented as
   a JSON [RFC4627] number.

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3.5.3.  zone_time_last

   This field returns the last time that the unique tuple (rrname,
   rrtype, rdata) record has been seen via master file import.  The date
   is expressed in seconds (decimal) since 1st of January 1970 (Unix
   timestamp).  The time zone MUST be UTC.  This field is represented as
   a JSON [RFC4627] number.

3.5.4.  origin

   Specifies the resource origin of the Passive DNS response.  This
   field is represented as a Uniform Resource Identifier [RFC3986] (URI)
   in the form of a JSON [RFC4627] string.

3.5.5.  time_first_ms

   Same meaning as the field "time_first", with the only difference,
   that the resolution is in milliseconds since 1st of January 1970
   (UTC).

3.5.6.  time_last_ms

   Same meaning as the field "time_last", with the only difference, that
   the resolution is in milliseconds since 1st of January 1970 (UTC).

3.6.  Additional Fields Registry

   In accordance with [RFC6648], designers of new passive DNS
   applications that would need additional fields can request and
   register new field name at https://github.com/adulau/pdns-qof/wiki/
   Additional-Fields.

3.7.  Additional notes

   An implementer of a passive DNS server MAY chose to either return
   time_first and time_last OR return zone_time_first and
   zone_time_last.  In pseudocode: (time_first AND time_last) OR
   (zone_time_first AND zone_time_last).  In this case,
   zone_time_{first,last} replace the time_{first,last} fields.
   However, this is not encouraged since it might be confusing for
   parsers who will expect the mandatory fields time_{first,last}. See:
   [github_issue_17]

3.8.  Suggested MIME Types

   An implementer of a passive DNS server SHOULD serve a document in
   this Common Output Format with a MIME header of "application/
   x-ndjson".

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4.  Acknowledgements

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

5.  IANA Considerations

   This memo includes no request to IANA.

6.  Privacy Considerations

   Passive DNS servers capture DNS answers from multiple collection
   points ("sensors") which are located on the Internet-facing side of
   DNS recursors ("post-recursor passive DNS").  In this process, they
   intentionally omit the source IP, source port, destination IP and
   destination port from the captured packets.  Since the data is
   captured "post-recursor", the timing information (who queries what)
   is lost, since the recursor will cache the results.  Furthermore,
   since multiple sensors feed into a passive DNS system, the resulting
   data gets mixed together, reducing the likelihood that Passive DNS
   systems are able to find out much about the actual person querying
   the DNS records.  In this sense, passive DNS systems are similar to
   keeping an archive of all previous phone books - if public DNS
   records can be compared to phone numbers - as they often are.
   Nevertheless, the authors strongly encourage Passive DNS implementors
   to take special care of privacy issues.  Finally, the overall
   recommendations in RFC6973 [RFC6973] should be taken into
   consideration when designing any application which uses Passive DNS
   data.

   Passive DNS attempts to collect information necessary for security
   (such as malware protection) in as privacy protecting a manner as
   possible, and is intended to be used instead of more invasive
   methods.  It does this by only collecting DNS cache-fill answers, and
   not any information associated with who caused the name to be
   resolved, nor why the name was resolved.  Nevertheless, it is
   possible that this may still lead to privacy concerns - for example,
   if Passive DNS records show that a recursive resolver resolved the
   name the-mary-and-john-smith-family.example.com, it may be possible
   to infer that the Smith family is using that resolver.  Operators of
   Passive DNS servers should be aware of this and take appropriate
   steps to limit access to the data.

   Passive DNS operators are encouraged to read and understand RFC7258
   [RFC7258]

   In the scope of the General Data Protection Regulation (GDPR -
   Directive 95/46/EC), operators of Passive DNS server needs to ensure
   the legal ground and lawfulness of its operation.

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7.  Security Considerations

   In some cases, Passive DNS output might contain confidential
   information and its access should be restricted.  When a user is
   querying multiple Passive DNS and aggregating the data, the
   sensitivity of the data must be considered.

8.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC3912]  Daigle, L., "WHOIS Protocol Specification", RFC 3912,
              DOI 10.17487/RFC3912, September 2004,
              <https://www.rfc-editor.org/info/rfc3912>.

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627,
              DOI 10.17487/RFC4627, July 2006,
              <https://www.rfc-editor.org/info/rfc4627>.

   [RFC3597]  Gustafsson, A., "Handling of Unknown DNS Resource Record
              (RR) Types", RFC 3597, DOI 10.17487/RFC3597, September
              2003, <https://www.rfc-editor.org/info/rfc3597>.

   [RFC6648]  Saint-Andre, P., Crocker, D., and M. Nottingham,
              "Deprecating the "X-" Prefix and Similar Constructs in
              Application Protocols", BCP 178, RFC 6648,
              DOI 10.17487/RFC6648, June 2012,
              <https://www.rfc-editor.org/info/rfc6648>.

   [RFC2234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 2234, DOI 10.17487/RFC2234,
              November 1997, <https://www.rfc-editor.org/info/rfc2234>.

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   [RFC6973]  Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
              Morris, J., Hansen, M., and R. Smith, "Privacy
              Considerations for Internet Protocols", RFC 6973,
              DOI 10.17487/RFC6973, July 2013,
              <https://www.rfc-editor.org/info/rfc6973>.

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC7258]  Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
              Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
              2014, <https://www.rfc-editor.org/info/rfc7258>.

   [WEIMERPDNS]
              Weimer, F., "Passive DNS Replication", 2005,
              <http://www.enyo.de/fw/software/dnslogger/
              first2005-paper.pdf>.

   [PDNSCOF]  Dulaunoy, D. P. A., "Passive DNS server interface using
              the common output format", 2019,
              <https://github.com/D4-project/analyzer-d4-passivedns/>.

   [github_issue_17]
              et.al, P. V. W. A. K., "Discussion on the existing
              implementations of returning either zone_time{first,last}
              OR time_{first,last}", 2020,
              <https://github.com/adulau/pdns-qof/issues/17>.

9.  Informative References

   [RFC7871]  Contavalli, C., van der Gaast, W., Lawrence, D., and W.
              Kumari, "Client Subnet in DNS Queries", RFC 7871,
              DOI 10.17487/RFC7871, May 2016,
              <https://www.rfc-editor.org/info/rfc7871>.

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

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

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

   [DNSDB]    Security, F., "DNSDB API", 2013,
              <https://api.dnsdb.info/>.

   [PDNSCERTAT]
              CERT.at, "pDNS presentation at 4th Centr R&D workshop
              Frankfurt Jun 5th 2012", 2012,
              <http://www.centr.org/system/files/agenda/attachment/d4-
              papst-passive_dns.pdf>.

   [PDNSCIRCL]
              Luxembourg, C. -. I. R. C., "CIRCL Passive DNS", 2012,
              <https://www.circl.lu/services/passive-dns/>.

   [DNSDBQ]   Vixie, P., "DNSDB API Client, C Version", 2018,
              <https://github.com/dnsdb/dnsdbq>.

Appendix A.  Examples

   The JSON output are represented on multiple lines for readability but
   each JSON object should be on a single line.

   If you query a passive DNS for the rrname www.ietf.org, the passive
   dns common output format can be:

   {"count": 102, "time_first": 1298412391, "rrtype": "AAAA",
   "rrname": "www.ietf.org", "rdata": "2001:1890:1112:1::20",
   "time_last": 1302506851}
   {"count": 59, "time_first": 1384865833, "rrtype": "A",
   "rrname": "www.ietf.org", "rdata": "4.31.198.44",
   "time_last": 1389022219}

                                  Figure 2

   If you query a passive DNS for the rrname ietf.org, the passive dns
   common output format can be:

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   {"count": 109877, "time_first": 1298398002, "rrtype": "NS",
   "rrname": "ietf.org", "rdata": "ns1.yyz1.afilias-nst.info",
   "time_last": 1389095375}
   {"count": 4, "time_first": 1298495035, "rrtype": "A",
   "rrname": "ietf.org", "rdata": "64.170.98.32",
   "time_last": 1298495035}
   {"count": 9, "time_first": 1317037550, "rrtype": "AAAA",
   "rrname": "ietf.org", "rdata": "2001:1890:123a::1:1e",
   "time_last": 1330209752}

                                  Figure 3

   Please note that the examples imply that a single query returns a
   single set of JSON objects.  For example, two queries were made; one
   query returned a set of two JSON objects and the other query returned
   a set of three JSON objects.  This specification requires each JSON
   object individually MUST conform to the common output format, but
   this specification does not require that a query will return a set of
   JSON objects.

   Please note that in the examples above, any backslashes "\" can be
   ignored and are an artifact of the tools which produced this
   document.

Authors' Addresses

   Alexandre Dulaunoy
   CIRCL
   122, rue Adolphe Fischer
   L-L-1521 Luxembourg
   Luxembourg
   Phone: (+352) 247 88444
   Email: alexandre.dulaunoy@circl.lu
   URI:   http://www.circl.lu/

   L. Aaron Kaplan
   A-1170 Vienna
   Austria
   Email: aaron@lo-res.org

   Paul Vixie
   Farsight Security, Inc.
   11400 La Honda Road
   Woodside, California 94062
   United States of America
   Email: paul@redbarn.org

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   URI:   https://www.farsightsecurity.com/

   Henry Stern
   Farsight Security, Inc.
   11400 La Honda Road
   Woodside, California 94062
   United States of America
   Phone: +1 650 542-7836
   Email: henry@stern.ca
   URI:   https://www.farsightsecurity.com/

   Warren Kumari
   Google
   Email: warren@kumari.net

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