mirror of
https://github.com/adulau/pdns-qof.git
synced 2024-11-21 09:37:07 +00:00
Compare commits
5 commits
a3875a15b4
...
3c659e9616
| Author | SHA1 | Date | |
|---|---|---|---|
3c659e9616
|
|||
|
a96d6e9f87
|
|||
| de636a7937 | |||
|
b7fdcf4187 | ||
|
|
473ee5c228 |
4 changed files with 464 additions and 363 deletions
1
.gitignore
vendored
1
.gitignore
vendored
|
|
@ -1,2 +1 @@
|
|||
*.swp
|
||||
|
||||
|
|
|
|||
BIN
i-d/pdns-qof.pdf
BIN
i-d/pdns-qof.pdf
Binary file not shown.
512
i-d/pdns-qof.txt
512
i-d/pdns-qof.txt
|
|
@ -5,21 +5,21 @@
|
|||
Domain Name System Operations A. Dulaunoy
|
||||
Internet-Draft CIRCL
|
||||
Intended status: Informational A. Kaplan
|
||||
Expires: 29 October 2024
|
||||
Expires: 28 February 2025
|
||||
P. Vixie
|
||||
H. Stern
|
||||
Farsight Security, Inc.
|
||||
W. Kumari
|
||||
Google
|
||||
27 April 2024
|
||||
27 August 2024
|
||||
|
||||
|
||||
Passive DNS - Common Output Format
|
||||
draft-dulaunoy-dnsop-passive-dns-cof-11
|
||||
draft-dulaunoy-dnsop-passive-dns-cof-12
|
||||
|
||||
Abstract
|
||||
|
||||
This document describes a common output format of Passive DNS Servers
|
||||
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,
|
||||
|
|
@ -41,7 +41,7 @@ Status of This Memo
|
|||
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 29 October 2024.
|
||||
This Internet-Draft will expire on 28 February 2025.
|
||||
|
||||
Copyright Notice
|
||||
|
||||
|
|
@ -53,9 +53,9 @@ Copyright Notice
|
|||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 1]
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 1]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
This document is subject to BCP 78 and the IETF Trust's Legal
|
||||
|
|
@ -70,80 +70,114 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
Table of Contents
|
||||
|
||||
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
|
||||
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
|
||||
2. Limitation . . . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . . 5
|
||||
3.3.2. rrtype . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . 6
|
||||
3.4. Optional Fields . . . . . . . . . . . . . . . . . . . . . 6
|
||||
3.4.1. count . . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . 7
|
||||
3.5.4. origin . . . . . . . . . . . . . . . . . . . . . . . 7
|
||||
3.5.5. time_first_ms . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . . . 8
|
||||
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
|
||||
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 8
|
||||
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
|
||||
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
|
||||
8.1. Normative References . . . . . . . . . . . . . . . . . . 9
|
||||
8.2. References . . . . . . . . . . . . . . . . . . . . . . . 10
|
||||
8.3. Informative References . . . . . . . . . . . . . . . . . 11
|
||||
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 11
|
||||
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
|
||||
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
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 2]
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 2]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
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]. Since then, multiple Passive DNS
|
||||
implementations were created and have evolved over time. Users of
|
||||
these Passive DNS servers may query a server (often via WHOIS
|
||||
[RFC3912] or HTTP REST [REST]), parse the results, and process them
|
||||
in other applications.
|
||||
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.
|
||||
|
||||
There are multiple implementations 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 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 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.
|
||||
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
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 3]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
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
|
||||
|
||||
|
|
@ -151,26 +185,18 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
|
||||
document are to be interpreted as described in RFC 2119 [RFC2119].
|
||||
|
||||
2. Limitation
|
||||
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 [CACHEPOISONING]. 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
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 3]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
|
||||
identical across multiple Passive DNS Servers.
|
||||
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
|
||||
|
||||
|
|
@ -192,6 +218,14 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
|
||||
Formal grammar as defined in ABNF [RFC2234]
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 4]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
answer = entries
|
||||
entries = * ( entry newline )
|
||||
entry = ws "{" ws keyvallist ws "}" ws
|
||||
|
|
@ -215,16 +249,7 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
)
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 4]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
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.
|
||||
|
|
@ -246,6 +271,17 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
Senders SHOULD send an array for rdata, but receivers MUST be able to
|
||||
accept a single-string result for rdata.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 5]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
3.3.1. rrname
|
||||
|
||||
This field returns the name of the queried resource. Represented as
|
||||
|
|
@ -268,20 +304,6 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
a decimal value (as mentioned above) answer represented as a JSON
|
||||
[RFC4627] number.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 5]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
|
||||
3.3.3. rdata
|
||||
|
||||
This field returns the resource records of the queried resource.
|
||||
|
|
@ -306,6 +328,16 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
timestamp). The time zone MUST be UTC. This field is represented as
|
||||
a JSON [RFC4627] number.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 6]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
3.3.5. time_last
|
||||
|
||||
This field returns the last time that the unique tuple (rrname,
|
||||
|
|
@ -321,23 +353,12 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
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
|
||||
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.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 6]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
|
||||
3.4.2. bailiwick
|
||||
|
||||
The bailiwick is the best estimate of the apex of the zone where this
|
||||
|
|
@ -365,6 +386,14 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
timestamp). The time zone MUST be UTC. This field is represented as
|
||||
a JSON [RFC4627] number.
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 7]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
3.5.3. zone_time_last
|
||||
|
||||
This field returns the last time that the unique tuple (rrname,
|
||||
|
|
@ -385,15 +414,6 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
that the resolution is in milliseconds since 1st of January 1970
|
||||
(UTC).
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 7]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
|
||||
3.5.6. time_last_ms
|
||||
|
||||
Same meaning as the field "time_last", with the only difference, that
|
||||
|
|
@ -408,7 +428,7 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
|
||||
3.7. Additional notes
|
||||
|
||||
An implementer of a passive DNS Server MAY chose to either return
|
||||
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,
|
||||
|
|
@ -419,10 +439,17 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
|
||||
3.8. Suggested MIME Types
|
||||
|
||||
An implementer of a passive DNS Server SHOULD serve a document in
|
||||
An implementer of a passive DNS server SHOULD serve a document in
|
||||
this Common Output Format with a MIME header of "application/
|
||||
x-ndjson".
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 8]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
4. Acknowledgements
|
||||
|
||||
Thanks to the Passive DNS developers who contributed to the document.
|
||||
|
|
@ -433,134 +460,131 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
|
||||
6. Privacy Considerations
|
||||
|
||||
Passive DNS Servers capture DNS answers from multiple collection
|
||||
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 server, the resulting
|
||||
since multiple sensors feed into a passive DNS system, the resulting
|
||||
data gets mixed together, reducing the likelihood that Passive DNS
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 8]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
|
||||
Servers are able to find out much about the actual person querying
|
||||
the DNS records. In this sense, passive DNS Servers are similar to
|
||||
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. bortzmeyer-dnsop-dns-privacy
|
||||
is an excellent starting point for this. Finally, the overall
|
||||
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
|
||||
Directive 95/46/EC), operators of Passive DNS server needs to ensure
|
||||
the legal ground and lawfulness of its operation.
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 9]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
7. Security Considerations
|
||||
|
||||
In some cases, Passive DNS output might contain confidential
|
||||
information and its access might be restricted. When a user is
|
||||
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. References
|
||||
|
||||
8.1. Normative References
|
||||
|
||||
[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>.
|
||||
|
||||
[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>.
|
||||
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>.
|
||||
|
||||
[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>.
|
||||
|
||||
[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>.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 9]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
[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>.
|
||||
|
||||
[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>.
|
||||
|
||||
[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>.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 10]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
[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>.
|
||||
|
||||
8.2. References
|
||||
[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>.
|
||||
|
||||
[BAILIWICK]
|
||||
Edmonds, R., "Passive DNS Hardening", 2010,
|
||||
<https://archive.farsightsecurity.com/Passive_DNS/
|
||||
passive_dns_hardening_handout.pdf>.
|
||||
[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>.
|
||||
|
||||
[CACHEPOISONING]
|
||||
Kaminsky, D., "Black ops 2008: It's the end of the cache
|
||||
as we know it.", 2008,
|
||||
<http://kurser.lobner.dk/dDist/DMK_BO2K8.pdf>.
|
||||
|
||||
[DNSDB] Security, F., "DNSDB API", 2013,
|
||||
<https://api.dnsdb.info/>.
|
||||
|
||||
[DNSDBQ] Vixie, P., "DNSDB API Client, C Version", 2018,
|
||||
<https://github.com/dnsdb/dnsdbq>.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 10]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
[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
|
||||
|
|
@ -568,6 +592,39 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
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>.
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 11]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
[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,
|
||||
|
|
@ -578,25 +635,8 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
Luxembourg, C. -. I. R. C., "CIRCL Passive DNS", 2012,
|
||||
<https://www.circl.lu/services/passive-dns/>.
|
||||
|
||||
[PDNSCLIENT]
|
||||
Lee, C., "Queries 5 major Passive DNS databases: BFK,
|
||||
CERTEE, DNSParse, ISC, and VirusTotal.", 2013,
|
||||
<https://github.com/chrislee35/passivedns-client>.
|
||||
|
||||
[PDNSCOF] Dulaunoy, D. P. A., "Passive DNS server interface using
|
||||
the common output format", 2019,
|
||||
<https://github.com/D4-project/analyzer-d4-passivedns/>.
|
||||
|
||||
[REST] Fielding, R. T., "Representational State Transfer (REST)",
|
||||
2000, <http://www.ics.uci.edu/~fielding/pubs/dissertation/
|
||||
rest_arch_style.htm>.
|
||||
|
||||
[WEIMERPDNS]
|
||||
Weimer, F., "Passive DNS Replication", 2005,
|
||||
<http://www.enyo.de/fw/software/dnslogger/
|
||||
first2005-paper.pdf>.
|
||||
|
||||
8.3. Informative References
|
||||
[DNSDBQ] Vixie, P., "DNSDB API Client, C Version", 2018,
|
||||
<https://github.com/dnsdb/dnsdbq>.
|
||||
|
||||
Appendix A. Examples
|
||||
|
||||
|
|
@ -606,18 +646,6 @@ Appendix A. Examples
|
|||
If you query a passive DNS for the rrname www.ietf.org, the passive
|
||||
dns common output format can be:
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 11]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
|
||||
{"count": 102, "time_first": 1298412391, "rrtype": "AAAA",
|
||||
"rrname": "www.ietf.org", "rdata": "2001:1890:1112:1::20",
|
||||
"time_last": 1302506851}
|
||||
|
|
@ -625,9 +653,27 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
"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:
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 12]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
{"count": 109877, "time_first": 1298398002, "rrtype": "NS",
|
||||
"rrname": "ietf.org", "rdata": "ns1.yyz1.afilias-nst.info",
|
||||
"time_last": 1389095375}
|
||||
|
|
@ -638,6 +684,8 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
"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
|
||||
|
|
@ -655,7 +703,7 @@ Authors' Addresses
|
|||
Alexandre Dulaunoy
|
||||
CIRCL
|
||||
122, rue Adolphe Fischer
|
||||
L-1521 Luxembourg
|
||||
L-L-1521 Luxembourg
|
||||
Luxembourg
|
||||
Phone: (+352) 247 88444
|
||||
Email: alexandre.dulaunoy@circl.lu
|
||||
|
|
@ -668,18 +716,20 @@ Authors' Addresses
|
|||
Email: aaron@lo-res.org
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 12]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format April 2024
|
||||
|
||||
|
||||
Paul Vixie
|
||||
Farsight Security, Inc.
|
||||
11400 La Honda Road
|
||||
Woodside, California 94062
|
||||
United States of America
|
||||
Email: paul@redbarn.org
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 13]
|
||||
|
||||
Internet-Draft Passive DNS - Common Output Format August 2024
|
||||
|
||||
|
||||
URI: https://www.farsightsecurity.com/
|
||||
|
||||
|
||||
|
|
@ -725,4 +775,10 @@ Internet-Draft Passive DNS - Common Output Format April 2024
|
|||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 29 October 2024 [Page 13]
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
Dulaunoy, et al. Expires 28 February 2025 [Page 14]
|
||||
|
|
|
|||
228
i-d/pdns-qof.xml
228
i-d/pdns-qof.xml
|
|
@ -1,30 +1,38 @@
|
|||
<?xml version="1.0" encoding="US-ASCII"?>
|
||||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<?xml-model href="rfc7991bis.rnc"?> <!-- Required for schema validation and schema-aware editing -->
|
||||
<?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?>
|
||||
|
||||
<!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
|
||||
<!DOCTYPE rfc [
|
||||
|
||||
<!ENTITY RFC2119 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml">
|
||||
<!ENTITY RFC2629 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2629.xml">
|
||||
<!ENTITY RFC1035 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.1035.xml">
|
||||
<!ENTITY RFC1034 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.1034.xml">
|
||||
<!ENTITY RFC4627 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4627.xml">
|
||||
<!ENTITY RFC1035 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.1035.xml">
|
||||
<!ENTITY RFC2119 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml">
|
||||
<!ENTITY RFC2234 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2234.xml">
|
||||
<!ENTITY RFC2629 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2629.xml">
|
||||
<!ENTITY RFC3597 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3597.xml">
|
||||
<!ENTITY RFC3912 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3912.xml">
|
||||
<!ENTITY RFC6648 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6648.xml">
|
||||
<!ENTITY RFC2234 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2234.xml">
|
||||
<!ENTITY RFC6973 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6973.xml">
|
||||
<!ENTITY RFC3986 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3986.xml">
|
||||
<!ENTITY RFC4627 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4627.xml">
|
||||
<!ENTITY RFC6648 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6648.xml">
|
||||
<!ENTITY RFC6973 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.6973.xml">
|
||||
<!ENTITY RFC7258 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.7258.xml">
|
||||
<!ENTITY RFC7871 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.7871.xml">
|
||||
<!ENTITY I-D.narten-iana-considerations-rfc2434bis SYSTEM "http://xml.resource.org/public/rfc/bibxml3/reference.I-D.narten-iana-considerations-rfc2434bis.xml">
|
||||
<!ENTITY I-D.draft-bortzmeyer-dnsop-dns-privacy SYSTEM "http://xml.resource.org/public/rfc/bibxml3/reference.I-D.draft-bortzmeyer-dnsop-dns-privacy">
|
||||
]>
|
||||
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt'?>
|
||||
<?rfc strict="yes"?>
|
||||
<?rfc toc="yes"?>
|
||||
<?rfc tocdepth="4"?>
|
||||
<?rfc symrefs="yes"?>
|
||||
<?rfc sortrefs="yes"?>
|
||||
<?rfc compact="yes"?>
|
||||
<?rfc subcompact="no"?>
|
||||
<rfc category="info" docName="draft-dulaunoy-dnsop-passive-dns-cof-12" ipr="trust200902">
|
||||
|
||||
|
||||
<rfc
|
||||
xmlns:xi="http://www.w3.org/2001/XInclude"
|
||||
category="info"
|
||||
docName="draft-dulaunoy-dnsop-passive-dns-cof-12"
|
||||
ipr="trust200902"
|
||||
obsoletes=""
|
||||
updates=""
|
||||
submissionType="IETF"
|
||||
xml:lang="en"
|
||||
version="3">
|
||||
|
||||
<!-- ***** FRONT MATTER ***** -->
|
||||
<front>
|
||||
<title abbrev="Passive DNS - Common Output Format">Passive DNS - Common Output Format</title>
|
||||
|
|
@ -97,12 +105,12 @@
|
|||
</address>
|
||||
</author>
|
||||
|
||||
<date day="5" month="June" year="2024" />
|
||||
<date day="27" month="August" year="2024" />
|
||||
<area>General</area>
|
||||
<workgroup>Domain Name System Operations</workgroup>
|
||||
<keyword>dns</keyword>
|
||||
<abstract>
|
||||
<t>This document describes a common output format of Passive DNS Servers that clients can
|
||||
<t>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.</t>
|
||||
|
|
@ -111,29 +119,63 @@
|
|||
<middle>
|
||||
<section title="Introduction">
|
||||
<t>Passive DNS is a technique described by Florian Weimer in 2005 in <xref target="WEIMERPDNS">Passive
|
||||
DNS replication, F Weimer - 17th Annual FIRST Conference on Computer Security</xref>. Since
|
||||
then, multiple Passive DNS implementations were created and have evolved over time. Users of
|
||||
these Passive DNS servers may query a server (often via <xref target="RFC3912">WHOIS</xref>
|
||||
or HTTP <xref target="REST">REST</xref>), parse the results, and process them in other
|
||||
applications.</t>
|
||||
DNS replication, F Weimer - 17th Annual FIRST Conference on Computer Security</xref>.
|
||||
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.</t>
|
||||
|
||||
<t> There are multiple implementations 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 four Passive DNS Systems (<xref target="DNSDB" />, <xref target="DNSDBQ" />
|
||||
, <xref target="PDNSCERTAT" />, <xref target="PDNSCIRCL" /> and <xref target="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 <xref target="RFC4627">JSON</xref>
|
||||
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. <xref target="PDNSCLIENT">passivedns-client</xref> currently
|
||||
implements multiple parsers due to a lack of standardization. The document does not describe
|
||||
the protocol (e.g. <xref target="RFC3912">WHOIS</xref>, HTTP <xref target="REST">REST</xref>)
|
||||
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. </t>
|
||||
<t>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 <xref
|
||||
target="RFC7871">Client Subnet in DNS Queries</xref>) or to hide
|
||||
malicious behavior when queried from addresses known to be associated
|
||||
with security researchers.</t>
|
||||
|
||||
<t>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.
|
||||
</t>
|
||||
|
||||
<t>Multiple Passive DNS implementations and services exist. Users of
|
||||
these Passive DNS services may query a server (often via <xref
|
||||
target="RFC3912">WHOIS</xref>
|
||||
or HTTP <xref target="REST">REST</xref>), 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 (<xref
|
||||
target="DNSDB" />, <xref target="DNSDBQ" /> , <xref target="PDNSCERTAT"
|
||||
/>, <xref target="PDNSCIRCL" /> and <xref target="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 <xref target="RFC4627">JSON</xref>
|
||||
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.
|
||||
<xref target="PDNSCLIENT">passivedns-client</xref> currently implements
|
||||
multiple parsers due to a lack of standardization. The document does
|
||||
not describe the protocol (e.g. <xref target="RFC3912">WHOIS</xref>,
|
||||
HTTP <xref target="REST">REST</xref>) 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. </t>
|
||||
|
||||
<section title="Requirements Language">
|
||||
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD
|
||||
|
|
@ -142,15 +184,15 @@
|
|||
</section>
|
||||
</section>
|
||||
|
||||
<section title="Limitation">
|
||||
<section title="Limitations">
|
||||
<t> 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 <xref target="BAILIWICK">bailiwick algorithm</xref> protects
|
||||
the Passive DNS Database from <xref target="CACHEPOISONING">cache poisoning attacks</xref>.
|
||||
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. </t>
|
||||
will be identical across multiple Passive DNS servers. </t>
|
||||
</section>
|
||||
|
||||
<section title="Common Output Format">
|
||||
|
|
@ -168,8 +210,9 @@
|
|||
</section>
|
||||
|
||||
<section title="ABNF grammar">
|
||||
<!-- "preamble" is deprecated in V3 -->
|
||||
<t>Formal grammar as defined in <xref target="RFC2234">ABNF</xref></t>
|
||||
<figure>
|
||||
<preamble>Formal grammar as defined in <xref target="RFC2234">ABNF</xref></preamble>
|
||||
<artwork><![CDATA[
|
||||
answer = entries
|
||||
entries = * ( entry newline )
|
||||
|
|
@ -266,7 +309,7 @@ ws = *(
|
|||
<section title="Optional Fields">
|
||||
<t>Implementations SHOULD support one or more fields.</t>
|
||||
<section title="count">
|
||||
<t>Specifies how many authoritative DNS answers were received at the Passive DNS Server's
|
||||
<t>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 <xref
|
||||
|
|
@ -328,7 +371,7 @@ ws = *(
|
|||
</section>
|
||||
|
||||
<section title="Additional notes">
|
||||
<t>An implementer of a passive DNS Server MAY chose to either return time_first and
|
||||
<t>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
|
||||
|
|
@ -337,13 +380,12 @@ ws = *(
|
|||
</section>
|
||||
|
||||
<section title="Suggested MIME Types">
|
||||
<t>An implementer of a passive DNS Server SHOULD serve a document in this Common Output
|
||||
<t>An implementer of a passive DNS server SHOULD serve a document in this Common Output
|
||||
Format with a MIME header of "application/x-ndjson".</t>
|
||||
</section>
|
||||
</section>
|
||||
|
||||
|
||||
|
||||
<!-- This PI places the pagebreak correctly (before the section title) in the text output. -->
|
||||
<?rfc needLines="8"?>
|
||||
<section anchor="Acknowledgements" title="Acknowledgements">
|
||||
|
|
@ -355,39 +397,53 @@ ws = *(
|
|||
</section>
|
||||
|
||||
<section anchor="Privacy" title="Privacy Considerations">
|
||||
<t>Passive DNS Servers capture DNS answers from multiple collection points ("sensors") which
|
||||
<t>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 server, the resulting data gets
|
||||
mixed together, reducing the likelihood that Passive DNS Servers are able to find out much
|
||||
about the actual person querying the DNS records. In this sense, passive DNS Servers are
|
||||
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.
|
||||
bortzmeyer-dnsop-dns-privacy is an excellent starting point for this. Finally, the overall
|
||||
Passive DNS implementors to take special care of privacy issues. Finally, the overall
|
||||
recommendations in <xref target="RFC6973">RFC6973</xref> should be taken into consideration
|
||||
when designing any application which uses Passive DNS data.</t>
|
||||
|
||||
<t>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.</t>
|
||||
|
||||
<t>Passive DNS operators are encouraged to read and understand
|
||||
<xref target="RFC7258">RFC7258</xref> </t>
|
||||
|
||||
|
||||
<t>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
|
||||
operators of Passive DNS server needs to ensure the legal ground and lawfulness of its
|
||||
operation.</t>
|
||||
</section>
|
||||
|
||||
<section anchor="Security" title="Security Considerations">
|
||||
<t>In some cases, Passive DNS output might contain confidential information and its access
|
||||
might be restricted. When a user is querying multiple Passive DNS and aggregating the data,
|
||||
should be restricted. When a user is querying multiple Passive DNS and aggregating the data,
|
||||
the sensitivity of the data must be considered.</t>
|
||||
</section>
|
||||
</middle>
|
||||
<!-- *****BACK MATTER ***** -->
|
||||
<back>
|
||||
|
||||
<references title="Normative References"><!--?rfc
|
||||
include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml"?--> &RFC2119; &RFC1035; &RFC1034; &RFC3912; &RFC4627;
|
||||
&RFC3597; &RFC6648; &RFC2234; &RFC6973; &RFC3986; </references>
|
||||
|
||||
<references>
|
||||
<name>Normative References</name>
|
||||
&RFC2119; &RFC1035; &RFC1034; &RFC3912; &RFC4627;
|
||||
&RFC3597; &RFC6648; &RFC2234; &RFC6973; &RFC3986;
|
||||
&RFC7258;
|
||||
|
||||
<reference anchor="WEIMERPDNS"
|
||||
target="http://www.enyo.de/fw/software/dnslogger/first2005-paper.pdf">
|
||||
<front>
|
||||
|
|
@ -397,14 +453,28 @@ ws = *(
|
|||
</front>
|
||||
</reference>
|
||||
|
||||
<reference anchor="CACHEPOISONING" target="http://kurser.lobner.dk/dDist/DMK_BO2K8.pdf">
|
||||
<reference anchor="PDNSCOF" target="https://github.com/D4-project/analyzer-d4-passivedns/">
|
||||
<front>
|
||||
<title>Black ops 2008: It's the end of the cache as we know it.</title>
|
||||
<author fullname="Dan Kaminsky" />
|
||||
<date year="2008" />
|
||||
<title>Passive DNS server interface using the common output format</title>
|
||||
<author fullname="D4 Project, Alexandre Dulaunoy" />
|
||||
<date year="2019" />
|
||||
</front>
|
||||
</reference>
|
||||
|
||||
<reference anchor="github_issue_17" target="https://github.com/adulau/pdns-qof/issues/17">
|
||||
<front>
|
||||
<title>Discussion on the existing implementations of returning either
|
||||
zone_time{first,last} OR time_{first,last}</title>
|
||||
<author fullname="Paul Vixie, Weizman, April, Kaplan, et.al" />
|
||||
<date year="2020" />
|
||||
</front>
|
||||
</reference>
|
||||
</references>
|
||||
|
||||
<references>
|
||||
<name>Informative References</name>
|
||||
&RFC7871;
|
||||
|
||||
<reference anchor="BAILIWICK"
|
||||
target="https://archive.farsightsecurity.com/Passive_DNS/passive_dns_hardening_handout.pdf">
|
||||
<front>
|
||||
|
|
@ -456,14 +526,6 @@ ws = *(
|
|||
</front>
|
||||
</reference>
|
||||
|
||||
<reference anchor="PDNSCOF" target="https://github.com/D4-project/analyzer-d4-passivedns/">
|
||||
<front>
|
||||
<title>Passive DNS server interface using the common output format</title>
|
||||
<author fullname="D4 Project, Alexandre Dulaunoy" />
|
||||
<date year="2019" />
|
||||
</front>
|
||||
</reference>
|
||||
|
||||
<reference anchor="DNSDBQ" target="https://github.com/dnsdb/dnsdbq">
|
||||
<front>
|
||||
<title>DNSDB API Client, C Version</title>
|
||||
|
|
@ -471,22 +533,6 @@ ws = *(
|
|||
<date year="2018" />
|
||||
</front>
|
||||
</reference>
|
||||
|
||||
<reference anchor="github_issue_17" target="https://github.com/adulau/pdns-qof/issues/17">
|
||||
<front>
|
||||
<title>Discussion on the existing implementations of returning either
|
||||
zone_time{first,last} OR time_{first,last}</title>
|
||||
<author fullname="Paul Vixie, Weizman, April, Kaplan, et.al" />
|
||||
<date year="2020" />
|
||||
</front>
|
||||
</reference>
|
||||
</references>
|
||||
|
||||
|
||||
<references title="Informative References">
|
||||
<!-- Here we use entities that we defined at the beginning. -->
|
||||
<!-- &I-D.narten-iana-considerations-rfc2434bis; -->
|
||||
<!-- &I-D.draft-bortzmeyer-dnsop-dns-privacy; -->
|
||||
</references>
|
||||
|
||||
<section anchor="app-additional" title="Examples">
|
||||
|
|
|
|||
Loading…
Reference in a new issue