| Internet-Draft | RATS Security Considerations | October 2025 |
| Sardar | Expires 23 April 2026 | [Page] |
This document aims to provide guidelines and best practices for writing security considerations for technical specifications for RATS targeting the needs of implementers, researchers, and protocol designers.¶
This note is to be removed before publishing as an RFC.¶
The latest revision of this draft can be found at https://muhammad-usama-sardar.github.io/rats-sec-cons/draft-rats-sardar-sec-cons.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-rats-sardar-sec-cons/.¶
Source for this draft and an issue tracker can be found at https://github.com/muhammad-usama-sardar/rats-sec-cons.¶
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While [I-D.irtf-cfrg-cryptography-specification] provides excellent guidelines, remote attestation [RFC9334] has several distinguishing features which necessitate a separate document. One specific example of such feature is architectural complexity.¶
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.¶
[Gen-Approach] proposes general hierarchy of one-way authentication, which can help precisely state the intended level of authentication (in decreasing order):¶
Recentness can be added to each of these levels of authentication.¶
Security considerations in RATS specifications need to clarify how the following attacks are avoided or mitigated:¶
Diversion attacks [Meeting-122-TLS-Slides]¶
Relay attacks¶
Replay attacks¶
Section 7.4 of [RFC9334] has:¶
A conveyance protocol that provides authentication and integrity protection can be used to convey Evidence that is otherwise unprotected (e.g., not signed).¶
Using a conveyance protocol that provides authentication and integrity protection, such as TLS 1.3 [RFC8446], to convey Evidence that is otherwise unprotected (e.g., not signed) undermines all security of remote attestation. Essentially, this breaks the chain up to the trust anchor (such as hardware manufacturer) for remote attestation. Hence, remote attestation effectively provides no protection in this case and the security guarantees are limited to those of the conveyance protocol only. In order to benefit from remote attestation, Evidence MUST be protected using dedicated keys chaining back to the trust anchor for remote attestation.¶
Identity Supplier and its corresponding conceptual message Identity are missing and need to be added to the architecture [Tech-Concepts].¶
Attestation Challenge as conceptual message needs to be added to the architecture [Tech-Concepts].¶
We believe that the following drafts are detrimental for the RATS ecosystem:¶
Multi-Verifiers [I-D.deshpande-rats-multi-verifier]: the design of multi-verifiers not only increase security risks in terms of increasing the Trusted Computing Base (TCB), but also increases the privacy risks, as potentially sensitive information is sent to multiple verifiers.¶
Aggregator-based design [I-D.ietf-rats-coserv]: Aggregator is an explicit trust anchor and the addition of new trust anchor needs to have a strong justification.¶
All of this document is about security considerations.¶
This document has no IANA actions.¶
The author wishes to thank Ira McDonald for insightful discussion. The author also gratefully acknowledges the authors of [I-D.irtf-cfrg-cryptography-specification], which serves as the inspiration of this work.¶