Internet DRAFT - draft-vyncke-opsec-probe-attribution
draft-vyncke-opsec-probe-attribution
Operational Security Capabilities for IP Network InfrastructureE. Vyncke
Internet-Draft Cisco
Intended status: Informational B. Donnet
Expires: 4 September 2022 J. Iurman
Université de Liège
3 March 2022
Attribution of Internet Probes
draft-vyncke-opsec-probe-attribution-01
Abstract
Active measurements at Internet-scale can target either collaborating
parties or non-collaborating ones. This is similar scan and could be
perceived as aggressive. This document proposes a couple of simple
techniques allowing any party or organization to understand what this
unsolicited packet is, what is its purpose, and more importantly who
to contact.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://evyncke.github.io/opsec-probe-attribution/draft-vyncke-opsec-
probe-attribution.html. Status information for this document may be
found at https://datatracker.ietf.org/doc/draft-vyncke-opsec-probe-
attribution/.
Discussion of this document takes place on the Operational Security
Capabilities for IP Network Infrastructure Working Group mailing list
(mailto:opsec@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/opsec/.
Source for this draft and an issue tracker can be found at
https://github.com/evyncke/opsec-probe-attribution.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Probe / Measurement Description . . . . . . . . . . . . . . . 3
2.1. Probe Description URI . . . . . . . . . . . . . . . . . . 3
2.2. Probe Description Text . . . . . . . . . . . . . . . . . 3
3. Out-of-band Probe Attribution . . . . . . . . . . . . . . . . 4
4. In-band Probe Attribution . . . . . . . . . . . . . . . . . . 4
5. Ethical Considerations . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Active measurements at Internet-scale can target either collaborating
parties or non-collaborating ones. Such measurements include
[LARGE_SCALE] and [RFC7872].
Sending unsolicited probes should obviously be done at a rate low
enough to avoid wasting other parties resources. But even at a low
rate, those probes could trigger an alarm that will request some
investigation by either the party receiving the probe (i.e., when the
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probe destination address is one address assigned to the receiving
party) or by a third party having some devices where those probes are
transiting (e.g., an Internet transit router).
This document suggests a couple of simple techniques allowing any
party or organization to understand:
* what this unsolicited packet is,
* what is its purpose,
* and more significantly who to contact for further information or
stop the probing.
Note: it is expected that only good-willing researchers will use
these techniques.
2. Probe / Measurement Description
2.1. Probe Description URI
This document defines a "probe description URI" (see Section 2.2) as
a URI pointing to:
* a "Probe Description", see Section 2.2, e.g.,
"https://example.net/measurement.txt";
* an email address, e.g., "mailto:eric@example.net";
* a phone number to call, e.g., "tel:+1-201-555-0123".
2.2. Probe Description Text
Similarly, as in [I-D.draft-foudil-securitytxt], when a node probes
other nodes over the Internet, it should create a text file following
the syntax described in section 3 of [I-D.draft-foudil-securitytxt]
and should have the following fields:
* contact;
* expires;
* preferred-languages.
Plus, another one "description" which is a URI pointing a document
describing the measurement.
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3. Out-of-band Probe Attribution
When it is not possible to include the "probe description URI" in the
probe packet itself, then a specific URI must be constructed based on
the source address of the probe packet following [RFC8615], e.g., for
a probe source address of 2001:db8::dead, the following URI are
constructed:
* if the reverse DNS record for 2001:db8::dead exists, e.g.,
"example.net", then the URI is "https://example.net/.well-known/
probing.txt" ;
* else (or in addition), the URI is "https://[2001:db8::dead]/.well-
known/probing.txt". Of course, there will be a certificate
verification issue.
The constructed URI must be a reference to the "Probe description
Text" (see Section 2.2).
4. In-band Probe Attribution
When the desired measurement allows for it, one "probe description
URI" should be included in the payload of all probes sent. This
could be:
* for a [RFC4443] ICMPv6 echo request: in the optional data (see
section 4.1 of [RFC4443]);
* for a [RFC792] ICMPv4 echo request: in the optional data;
* for a [RFC768] UDP datagram: in the data part;
* for a [RFC793] TCP packet with the SYN flag: data is allowed in
TCP packets with the SYN flag per section 3.4 of [RFC793] (2nd
paragraph);
* for a [RFC8200] IPv6 packet with either hop-by-hop or destination
options headers, in the PadN option. Note that, per the
informational [RFC4942] section 2.1.9.5, it is suggested that PadN
option should only contain 0x0 and be smaller than 8 octets, so
the proposed insertion of the URI in PadN option could have
influence on the measurement itself;
* etc.
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The URI should start at the first octet of the payload and should be
terminated by an octet of 0x00, i.e., it must be null terminated. If
the URI cannot be placed at the beginning of the payload, then it
should be preceded also by an octet of 0x00.
Note: using the above technique produces a valid and legit packet for
all the nodes forwarding the probe. The node receiving the probe may
or may not process the received packet, but this should cause no harm
if the probing rate is very low as compared to the network bandwidth
and to the processing capacity of all the nodes. As the insertion of
the URI in the packet may not respect the syntax of the protocol,
responses may not be received (such a TCP SYN+ACK) and perhaps an
ICMP should be expected or more probably an absence of reply.
5. Ethical Considerations
Executing some measurement experiences over the global Internet
obviously require some ethical considerations when transit/
destination non-solicited parties are involved.
This document proposes a common way to identity the source and the
purpose of active probing in order to reduce the potential burden on
the non-solicited parties.
But there are other considerations to be taken into account: from the
payload content (e.g., is the encoding valid ?) to the transmission
rate (see also [IPV6_TOPOLOGY] and [IPV4_TOPOLOGY] for some probing
speed impacts). Those considerations are out of scope of this
document.
6. Security Considerations
While it is expected that only good-willing researchers will use
these techniques, they will simplify and shorten the time to identify
a probing across the Internet.
This information is provided to identify the source and intent of
specific probes, but there is no authentication possible for the
inline information. As a result, a malevolent actor could provide
false information while conducting the probes, so that the action was
attributed to a third party. The recipient of this information
cannot, as a result, rely on this information without confirmation.
If a recipient cannot confirm the information or does not wish to do
so, they should treat the flows as if there were no attribution.
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7. IANA Considerations
The "Well-Known URIs" registry should be updated with the following:
* additional values (using the template from [RFC8615]):
* URI suffix: probing.txt
* Change controller: IETF
* Specification document(s): this document
* Status: permanent
8. References
8.1. Normative References
[I-D.draft-foudil-securitytxt]
Foudil, E. and Y. Shafranovich, "A File Format to Aid in
Security Vulnerability Disclosure", Work in Progress,
Internet-Draft, draft-foudil-securitytxt-12, 24 May 2021,
<https://datatracker.ietf.org/doc/html/draft-foudil-
securitytxt-12>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", STD 89,
RFC 4443, DOI 10.17487/RFC4443, March 2006,
<https://www.rfc-editor.org/rfc/rfc4443>.
[RFC768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/rfc/rfc768>.
[RFC792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, DOI 10.17487/RFC0792, September 1981,
<https://www.rfc-editor.org/rfc/rfc792>.
[RFC793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, DOI 10.17487/RFC0793, September 1981,
<https://www.rfc-editor.org/rfc/rfc793>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/rfc/rfc8200>.
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[RFC8615] Nottingham, M., "Well-Known Uniform Resource Identifiers
(URIs)", RFC 8615, DOI 10.17487/RFC8615, May 2019,
<https://www.rfc-editor.org/rfc/rfc8615>.
8.2. Informative References
[IPV4_TOPOLOGY]
Beverly, R., "Yarrp’ing the Internet Randomized High-Speed
Active Topology Discovery", DOI 10.1145/2987443.2987479,
2016, <http://www.cmand.org/papers/yarrp-imc16.pdf>.
[IPV6_TOPOLOGY]
Beverly, R., Durairajan, R., Plonka, D., and J.P. Rohrer,
"In the IP of the Beholder Strategies for Active IPv6
Topology Discovery", DOI 10.1145/3278532.3278559, 2018,
<http://www.cmand.org/papers/beholder-imc18.pdf>.
[LARGE_SCALE]
Donnet, B., Raoult, P., Friedman, T., and M. Crovella,
"Efficient Algorithms for Large-Scale Topology Discovery",
DOI 10.1145/1071690.1064256, 2005,
<https://dl.acm.org/doi/pdf/10.1145/1071690.1064256>.
[RFC4942] Davies, E., Krishnan, S., and P. Savola, "IPv6 Transition/
Co-existence Security Considerations", RFC 4942,
DOI 10.17487/RFC4942, September 2007,
<https://www.rfc-editor.org/rfc/rfc4942>.
[RFC7872] Gont, F., Linkova, J., Chown, T., and W. Liu,
"Observations on the Dropping of Packets with IPv6
Extension Headers in the Real World", RFC 7872,
DOI 10.17487/RFC7872, June 2016,
<https://www.rfc-editor.org/rfc/rfc7872>.
Acknowledgments
The authors would like to thank Alain Fiocco, Fernando Gont, Ted
Hardie, Mehdi Kouhen, and Mark Townsley for helpful discussions as
well as Raphael Leas for an early implementation.
Authors' Addresses
Éric Vyncke
Cisco
De Kleetlaan 64
1831 Diegem
Belgium
Email: evyncke@cisco.com
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Benoît Donnet
Université de Liège
Belgium
Email: benoit.donnet@uliege.be
Justin Iurman
Université de Liège
Belgium
Email: justin.iurman@uliege.be
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