Internet-Draft | TIGRESS Threat Model | February 2023 |
Lassey | Expires 7 August 2023 | [Page] |
TODO Abstract¶
This note is to be removed before publishing as an RFC.¶
The latest revision of this draft can be found at https://bslassey.github.io/tigress-threat-model/draft-lassey-tigress-threat-model.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-lassey-tigress-threat-model/.¶
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Source for this draft and an issue tracker can be found at https://github.com/bslassey/tigress-threat-model.¶
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The TIGRESS Working Group is chartered to deliver a protocol for transferring copies of digital credentials. The charter specifies certain goals:¶
From these goals we can derive a threat model for the general problem space.¶
## Assets and Data ### Credential The credential or key that is being shared via this protocol. ### Intermediary data Data that is shared over the course of the transaction. ### Share invitation The initial data shared with the reciever which represents an invitation to share a credential. # Users ## Sender The user who initiates the share. ## Receiver The user who is the intended recipient and accepts the invitation to share a credential. # Attackers and Motivations # Threats and mitigations¶
Threat Description | Likelihood | Impact | Mitigations |
---|---|---|---|
An Attacker with physical access to the victim's phone initiates a share of a Credential to the the Attacker's device | MED | HIGH | Implementors SHOULD take sufficient precautions to ensure that the device owner is in possession of the device when initiating a share such as requiring authentication at share time |
Attacker intercepts or eavesdrops on sharing message | HIGH | HIGH | |
Sender mistakenly sends to the wrong Receiver | HIGH | HIGH | Implementors should ensure any initiated shares can be withdrawn or revoked at any time. |
Sender device compromised | MED | HIGH |
Some designs may rely on an intermediary server to facilitate the transfer of material. Below are threats and mitigations assuming that there is an intermediary server hosting encrypted content at an "unguessible" location.¶
Threat Description | Likelihood | Impact | Mitigations |
---|---|---|---|
Attacker brute forces "unguessible" location | LOW | LOW | Limited TTL of storage, rate limiting of requests |
Attacker intercepts encryption key | MED | MED | Seperate transimission of encryption key and unguessible location |
Attacker intercepts encryption key and unguessible location | MED | HIGH | Implementor should warn users about sharing credentials to groups |
Attacker compromises intermediary server | LOW | LOW | Content on the server is encrypted |
Attacker uses intermediary server to store unrelated items (i.e. cat pictures) | HIGH | LOW | intermediary server should have tight size limits and TTLS to discourage misuse |
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
This document has no IANA actions.¶
This document took as inspiration the threat model that was part of Dmitry Vinokurov's sample implementation document.¶