Hi Eliot, Scott,
Thanks for this document. Here is my AD review for
draft-ietf-opsawg-sbom-access-12.
Moderate level comments:
(1) p 3, sec 1. Introduction
To enable application-layer discovery, this memo defines a well-known
URI [RFC8615]. Management or orchestration tools can query this
well-known URI to retrieve a system's SBOM or vulnerability
information. Further queries may be necessary based on the content
and structure of the response.
It looks like the .wellknown URI can only be used to retrieve SBOM information
and not vulnerability information (unless I am missing something).
(2) p 15, sec 6. Security Considerations
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
This text looks to be inconsistent with earlier parts of the document,
specifically, I didn't think that the intent was to fetch this information
using NETCONF or RESTCONF, but the early part of this document states that it
contains groupings, which presumably could be used in any YANG model, and hence
security considerations would apply.
I would suggest that you split the security considerations into two separate
sub-sections:
i. The security considerations as this document applies to documenting SBOMs as
part of the MUD file. Which I think is most of the text that you have below.
As per above I think that it is this section that should be updated to comment
on the use of the insecure version of http and coap.
ii. A separate sub-section that only applies if the groupings are being used in
regular YANG modules accessed via NETCONF/RESTCONF and that follows the
standard YANG security template.
Minor level comments:
(3) p 0, sec
Discovering and Retrieving Software Transparency and Vulnerability
Information
draft-ietf-opsawg-sbom-access-12
It wasn't obvious to me why this is called "transparency", is this is a
standard term of art for SBOMs?
(4) p 4, sec 1.1. How This Information Is Retrieved
Note that vulnerability and SBOM information is likely to change at
different rates. MUD's cache-validity node provides a way for
manufacturers to control how often tooling should check for those
changes through the cache-validity node.
Just for my understanding: Is there any mechanism for clients to register for
notification of changes rather than polling?
(5) p 4, sec 2. The well-known transparency endpoint set
Two well known endpoint is defined:
"Two" => "a", and well known => well-known?
(6) p 7, sec 4. The mud-sbom augmentation to the MUD YANG model
identity http {
base mudtx:local-type;
description
"Use http (insecure) to retrieve SBOM information. This
method is NOT RECOMMENDED, but may be unavoidable for
certain classes of deployment, where TLS has not or
cannot be implemented";
}
I'm okay with this and coap (from a pragmatism POV). But I think that the
security section should talk about this: I.e., emphasize that secure versions
MUST be used in preference, if available, and highlight the risks if insecure
protocols are used.
(7) p 7, sec 4. The mud-sbom augmentation to the MUD YANG model
identity coaps {
base mudtx:local-type;
description
"Use COAPS (secure) to retrieve SBOM";
}
Possibly add YANG reference statements to point to the latest http, https,
coap, and coaps specifications?
(8) p 8, sec 4. The mud-sbom augmentation to the MUD YANG model
choice sbom-retrieval-method {
description
"How to find SBOM information";
case cloud {
list sboms {
key "version-info";
description
"A list of SBOMs tied to different software
or hardware versions.";
leaf version-info {
type string;
description
"The version to which this SBOM refers.";
}
leaf sbom-url {
type inet:uri;
description
"A statically located URL.";
}
Should any URI be allowed here, or should it be pattern restricted to http(s)
or coap(s)?
(9) p 8, sec 4. The mud-sbom augmentation to the MUD YANG model
leaf archive-list {
type inet:uri;
description
"This URI returns a JSON list of URLs that consist of
SBOMs that were previously published for this
device. Publication dates can found inside
the SBOMs.";
i. Why not "sbom-archive-list"?
ii. Please also reformat the description.
(10) p 8, sec 4. The mud-sbom augmentation to the MUD YANG model
}
choice vuln-retrieval-method {
description
"How to find vulnerability information";
case cloud {
Is cloud a slightly colloquial term? Would 'remote' or 'online' be more
general?
(11) p 8, sec 4. The mud-sbom augmentation to the MUD YANG model
leaf vuln-url {
type inet:uri;
description
"A statically located URL.";
Perhaps "A statically located URL that references the vulnerability
information"?
(12) p 9, sec 4. The mud-sbom augmentation to the MUD YANG model
}
}
case vuln-contact-info {
leaf contact-uri {
type inet:uri;
description
"This MUST be either a tel, http, https, or
mailto uri schema that customers can use to
contact someone for vulnerability information.";
i. Should this be "vuln-conctact-uri" (since the case statement doesn't appear
in the instance data). The alternative solution would be to introduce "sbom"
and "vuln" containers which would then force those containing identifiers into
the instance data.
ii. Should you not also have the same pattern statement that you also have for
sbom-contact-uri?
(13) p 10, sec 5.1. Without ACLS
This first MUD file demonstrates how to get SBOM and vulnerability
information without ACLs.
{
"ietf-mud:mud": {
"mud-version": 1,
"extensions": [
"ol",
"transparency"
],
"ol": {
"owners": [
"Copyright (c) Example, Inc. 2022. All Rights Reserved"
],
"spdx-tag": "0BSD"
},
Where is the "ol" extension defined. I would have thought that the top node
would need a prefix and name?
(14) p 16, sec 6. Security Considerations
SBOMs provide an inventory of software. If software is available to
an attacker, the attacker may well already be able to derive this
very same software inventory. When this information resides on the
endpoint itself, the endpoint SHOULD NOT provide unrestricted access
by default. Other servers that offer the data MAY restrict access to
SBOM information using appropriate authorization semantics within
HTTP. One way to do this would be to issue a certificate to the
client for this purpose after a registration process has taken place.
Another approach would involve the use of OAUTH in combination with a
In particular, if a system attempts to retrieve an SBOM via HTTP and
the client is not authorized, the server MUST produce an appropriate
error, with instructions on how to register a particular client.
federations of SBOM servers.
Editing error? "with a ... " and "federations of SBOM servers".
Nit level comments:
(15) p 0, sec
To improve cybersecurity posture, automation is necessary to locate
what software is running on a device, whether that software has known
vulnerabilities, and what, if any recommendations suppliers may have.
This memo extends the MUD YANG model to provide the locations of
software bills of materials and to vulnerability information.
I find the last sentence hard to read, e.g., the "to vulnerability ..."
(16) p 7, sec 4. The mud-sbom augmentation to the MUD YANG model
grouping transparency-extension {
description
"This grouping provides a means to describe the location of
software bills of material and vulnerability descriptions.";
container transparency {
description
"container of methods to get an SBOM.";
Please capitalize the first letter. Also, this container holds data other than
just how to get SBOMs, should the description reflect that?
Other grammar warnings generated by an automated tool (some may already be
flagged above):
Grammar Warnings:
Section: 1, draft text:
- on devices themselves - on a web site (e.g., via URI) - through some form of
out-of-band contact with the supplier.
Warning: Nowadays it's more common to write this as one word.
Suggested change: "website"
Section: 2, draft text:
Two well known endpoint is defined:
Warning: Possible agreement error. The noun 'endpoint' seems to be countable,
so consider using: endpoints.
Suggested change: "endpoints"
Section: 6, draft text:
Some of the readable data nodes in this YANG module may be considered sensitive
or vulnerable in some network environments.
Warning: If the text is a generality, 'of the' is not necessary.
Suggested change: "Some"
Section: 6, draft text:
Another approach would involve the use of OAUTH in combination with a In
particular, if a system attempts to retrieve an SBOM via HTTP and the client is
not authorized, the server MUST produce an appropriate error, with instructions
on how to register a particular client.
Warning: Use an instead of 'a' if the following word starts with a vowel
sound, e.g. 'an article', 'an hour'
Suggested change: "an"
Section: 6, draft text:
federations of SBOM servers.
Warning: This sentence does not start with an uppercase letter.
Suggested change: "Federations"
Regards,
Rob
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