Hi Victor,

(please keep the ospawg list in the reply as not all WG participants are in 
this list)

The document will point to rfc9525#section-7.1 for a discussion of the wildcard 
risks. 

> Even if wildcards are supported, they should at least be
> discouraged.

The proposed text adheres to the restrictions set in rfc9525. Is there any 
reason tacacs+ has to deviate from the guards/restrictions in 
rfc9525#section-6.3? 

Thank you. 

Cheers,
Med

> -----Message d'origine-----
> De : Viktor Dukhovni <[email protected]>
> Envoyé : mardi 29 avril 2025 16:05
> À : [email protected]
> Objet : [Last-Call] Re: Change to draft-ietf-opsawg-tacacs-tls13
> 
> 
> On Tue, Apr 29, 2025 at 01:48:21PM +0000, Douglas Gash (dcmgash)
> wrote:
> 
> > PROPOSED NEW TEXT:
> >
> >    For the client-side validation of presented TLS TACACS+ server
> >    identities, implementations MUST follow [RFC9525] validation
> >    techniques.  Identifier types DNS-ID, IP-ID, or SRV-ID are
> applicable
> >    for use with the TLS TACACS+ protocol, selected by operators
> >    depending upon the deployment design.  TLS TACACS+ does not
> use URI-
> >    IDs for TLS TACACS+ server identity verification.
> >
> >    Wildcards in TLS TACACS+ server identities simplify
> certificate
> >    management by allowing a single certificate to secure multiple
> >    servers in a deployment.  However, this introduces security
> risks, as
> >    compromising the private key of a wildcard certificate impacts
> all
> >    servers using it.  To address these risks, the guidelines in
> >    Section 6.3 of [RFC9525] MUST be followed, and the wildcard
> >    SHOULD be confined to a subdomain dedicated solely to
> >    TLS TACACS+ servers.
> 
> Shared private key compromise isn't the only risk of wildcard
> certificates, it is also possible for active MiTM attacks or DNS
> cache poisoning to transparently redirect connections between the
> various devices that share a wildcard certificate, an operator or
> automated script might then make configuration changes to the wrong
> device.
> 
> Also replacement of wildcard certificates is often performed in
> concert across all the devices that share the certificate, creating
> a potential single point of failure.
> 
> Even if wildcards are supported, they should at least be
> discouraged.
> How common is use of wildcard certificates in this context?  Are
> they really needed?  Or is this "convenience" a marginal behaviour
> to avoid?
> 
> --
>     Viktor.
> 
> --
> last-call mailing list -- [email protected] To unsubscribe send an
> email to [email protected]
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