Internet DRAFT - draft-richardson-saag-onpath-attacker
draft-richardson-saag-onpath-attacker
Security Area Working Group M. Richardson
Internet-Draft Sandelman Software Works
Updates: 4949 (if approved) J. Hoyland
Intended status: Informational Cloudflare Ltd.
Expires: 26 April 2023 23 October 2022
A taxonomy of eavesdropping attacks
draft-richardson-saag-onpath-attacker-03
Abstract
The terms on-path attacker and Man-in-the-Middle Attack have been
used in a variety of ways, sometimes interchangeably, and sometimes
meaning different things.
This document offers an update on terminology for network attacks. A
consistent set of terminology is important in describing what kinds
of attacks a particular protocol defends against, and which kinds the
protocol does not.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 26 April 2023.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Three kinds of attack . . . . . . . . . . . . . . . . . . . . 3
2.1. First Kind of attack . . . . . . . . . . . . . . . . . . 3
2.2. Second Kind of attack . . . . . . . . . . . . . . . . . . 4
2.3. Second Kind of attack with bypass . . . . . . . . . . . . 4
2.4. Third Kind of attack . . . . . . . . . . . . . . . . . . 5
3. Three proposals on terminology . . . . . . . . . . . . . . . 5
3.1. QUIC terms . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Malory/Man in various places . . . . . . . . . . . . . . 5
3.3. Council of Attackers . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
A number of terms have been used to describe attacks against
networks.
In the [dolevyao] paper, the attacker is assumed to be able to:
* view messages as they are transmitted
* selectively delete messages
* selectively insert or modify messages
Some authors refer to such an attacker as an "on-path" attacker
[reference], or a "Man-in-the-Middle" [reference]. This type of
attack is also refered to as a "monster-in-the-middle" attack.
Despite a broad consensus on what is meant by a MITM attack, there is
less agreement on the how to describe its variants. The term
"passive attacker" has been used in many cases to describe situations
where the attacker can only observe messages, but can not intercept,
modify or delete any messages.
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Another variant is the case where an eavesdropper is not on the
network path between the actual correspondants, and thus cannot drop
messages, they may be able to inject packets faster than the
correspondants, and thus beat legitimate packets in a race.
As summarised, there are three broad variations of the MITM attacker:
1. An on-path attacker that can view, delete and modify messages.
This is the Dolev-Yao attack.
2. An off-path attacker that can view messages and insert new
messages.
3. An off-path attacker that can only view messages.
2. Three kinds of attack
The attacks are numbered in this section as no consensus on naming
the attacks yet. In the diagrams below, the sender is named "Alice",
and the recipient is named "Bob", as is typical in many cryptographic
protocols [alicebob], as first introduced by [digisign].
The attacker is named "Mallory"
.-------. .-----.
| Alice |------------------>| Bob |
'-------' '-----'
Figure 1: Alice communicating with Bob
2.1. First Kind of attack
In this attack, the attacker is involved with the forwarding of the
packets. A firewall or network router is ideally placed for this
attack.
.-------. .=========. .-----.
| Alice |------| Mallory |------>| Bob |
'-------' '=========' '-----'
Figure 2: The first kind of attack
In this case Mallory can:
* view all packets
* selectively forward or drop any packet
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* modify any packets that is forwarded
* insert additional packets
2.2. Second Kind of attack
In this attack, the attacker is not involved with the forwarding of
the packets. The attacker receives a copy of packets that are sent.
This could be from, for instance, a mirror port or SPAN [span].
Alternatively, a copy of traffic may be obtained via passive
(optical) tap [fibertap]. This kind of attack is often associated
with Pervasive Monitoring [RFC7258].
.-------. .-----.
| Alice |---------.------------->| Bob |
'-------' | '-----'
v
.=========.
| Mallory |
'========='
Figure 3: The second kind of attack
In this case Mallory can:
* view all packets
2.3. Second Kind of attack with bypass
In some cases, Mallory may be able to send messages to Bob via
another route which due to some factor will arrive at Bob prior to
the original message from Alice.
.-------. .->--. .-----.
| Alice |---------------| | | .>| Bob |
'-------' | | | | | '-----'
| | | v | ^
| | | | | |
v '--> '->| |
.=========. |
|Mallory |---------------------'
'=========.
Figure 4: The second kind of attack with bypass
In that case Mallory can:
* view all packets
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* insert additional/copied packets into the stream
But Mallory will be unable to drop or modify the original packets.
Bob however, may be unable to distinguish packets from Alice vs
packets sent from Mallory that purport to be from Alice.
2.4. Third Kind of attack
The third kind of attack is one in which Mallory can not see any
packets from Alice. This is usually what is meant by an "off-path"
attack. Mallory can usually forge packets purporting to be from
Alice, but can never see Alice's actual packets.
.-------. .-----.
| Alice |--------------------------->| Bob |
'-------' '-----'
^
|
|
*********** |
* Mallory *---------------------'
***********
Figure 5: The third kind of attack
In this case Mallory can:
* insert additional packets
3. Three proposals on terminology
This document aspires to pick a single set of terms and explain them.
3.1. QUIC terms
[quic] ended up with a different taxonomy:
* on-path [Dolev-Yao]
* Limited on-path (cannot delete)
* Off-path
3.2. Malory/Man in various places
[malory] proposes:
* man-in-the-middle [Dolev-Yao]
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* man-on-the-side
* man-in-the-rough
Alternatively:
* Malory-in-the-middle [Dolev-Yao]
* Malory-on-the-side
* Malory-in-the-rough
3.3. Council of Attackers
[alliteration] proposes the "the council of attackers"
* malicious messenger [Dolev-Yao: who rewrites messages sent]
* oppressive observer [who uses your information against you]
* off-path attacker
4. Security Considerations
This document introduces a set of terminology that will be used in
many Security Considerations sections.
5. IANA Considerations
This document makes no IANA requests.
6. Acknowledgements
The SAAG mailing list.
7. Changelog
8. References
8.1. Normative References
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2",
FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007,
<https://www.rfc-editor.org/info/rfc4949>.
8.2. Informative References
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[alicebob] "Alice and Bob", 2020,
<https://en.wikipedia.org/wiki/Alice_and_Bob>.
[alliteration]
"Council of Attackers", 2020,
<https://mailarchive.ietf.org/arch/msg/saag/
R0uevzT0Vz9uqqaxiu98GtK1rks/>.
[digisign] Rivest, R. L., Shamir, A., and L. Adleman, "A method for
obtaining digital signatures and public-key
cryptosystems", February 1978,
<https://doi.org/10.1145/359340.359342>.
[dolevyao] "On the Security of Public Key Protocols", 1983,
<https://www.cs.huji.ac.il/~dolev/pubs/dolev-yao-ieee-
01056650.pdf>.
[fibertap] "Fiber Tap", 2020,
<https://en.wikipedia.org/wiki/Room_641A>.
[malory] "Man-in-the-Middle", 2020,
<https://mailarchive.ietf.org/arch/msg/saag/b26jvEz4NRHSm-
Xva6Lv5-L8QIA/>.
[quic] "QUIC terms for attacks", 2020,
<https://mailarchive.ietf.org/arch/msg/saag/
wTtDYlRAADMmgqd6Vhm8rFybr_g/>.
[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>.
[span] "Port Mirroring", 2020,
<https://en.wikipedia.org/wiki/Port_mirroring>.
Contributors
Eric Rescola
Email: ekr@rtfm.com
Lou Berger
Email: lberger@labn.net
Alan DeKok
Email: aland@deployingradius.com
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Christian Huitema
Email: huitema@huitema.net
Authors' Addresses
Michael Richardson
Sandelman Software Works
Email: mcr+ietf@sandelman.ca
Jonathan Hoyland
Cloudflare Ltd.
Email: jhoyland@cloudflare.com
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