Hi Mohamed,

I was about to write an email regarding OPSWAG recharter and how the WG will 
continue to address the operational issues with TACACS+ (which will remain even 
after the publication of tacacs-tls draft). The discussion you started on the 
expected level of work of the WG ("minor") and the proposal to clarify it make 
me feel this is the right time to do it.

TACACS+ is widely deployed for Authentication and Authorization on equipments 
in a lot of networks (large companies, telcos, etc.). Being supported by most 
vendors, having various functional benefits, and this large deployment base, it 
seems it is here to stay. As already discussed in [1], the protocol is old and 
suffers from two major security issues:

 1/ weak protection of traffic;
 2/ total reliance on passwords.

Bit flipping and other issues (which currently allow for trivial access to 
equipments) associated with 1/ will be addressed by what has been specified in 
tacacs-tls draft. This effort is a good step forward but does not address 2/, 
which is the fundamental problem of TACACS+. Even after equipments ship with 
tacacs-tls, administrators (or supervision tools, etc.) on networks with 
TACACS+ deployed will still disseminate their (usually unique full power) 
password, which will be available in cleartext on all the equipments under 
TACACS+ control. A TACACS+ domain is one where an attacker just has to 
compromise a single weaker equipment and wait for a cleartext password to 
arrive to then have valid credentials to access ALL the equipments.

My questions would be:
 - is the problem described above a subject to be addressed by the WG?
 - if it is, what is the expected way forward? Specifying support for pushing 
SSH public-keys (draft-dahm-opsawg-tacacs-security-01?)? or X.509 certificate 
anchors? Other options?
 - if it is not, where can it be addressed? What would be the way forward?

Cheers,

Arnaud

[1]: https://mailarchive.ietf.org/arch/msg/opsawg/vdhi_wqIOLTOA7CN42WYk__d2-g/

-----Message d'origine-----
De : mohamed.boucad...@orange.com <mohamed.boucad...@orange.com>
Envoyé : lundi 14 avril 2025 09:55
À : Gunter Van de Velde <gunter.van_de_ve...@nokia.com>; The IESG 
<i...@ietf.org>
Cc : opsawg-cha...@ietf.org; opsawg@ietf.org
Objet : [OPSAWG]Re: Gunter Van de Velde's No Objection on 
charter-ietf-opsawg-04-04: (with COMMENT)

Hi Gunter,

There are many OPS-related protocols out there for which we don't have a home 
(IPFIX, DIAMETER, etc.). OPSAWG should not be the place to develop major 
changes (e.g. new versions) of these protocols.

For example, we used to have opsawg be tagged as maintenance group for RADIUS 
(https://mailarchive.ietf.org/arch/msg/radext/ygSshqCzKe0uN5aPiN08U_k-gx8/). I 
wasn't personally happy with that at the time for the reasons mentioned in that 
thread. Happily, RADEXT was resurrected since then and has its own WG (which is 
the right thing to do).

I suggest we keep "minor" to make the scope clear. We can characterize it if 
needed, though.

Thank you.

Cheers,
Med

> -----Message d'origine-----
> De : Gunter Van de Velde via Datatracker <nore...@ietf.org> Envoyé :
> lundi 14 avril 2025 09:25 À : The IESG <i...@ietf.org> Cc :
> opsawg-cha...@ietf.org; opsawg@ietf.org Objet : Gunter Van de Velde's
> No Objection on charter-ietf-opsawg-
> 04-04: (with COMMENT)
>
>
> Gunter Van de Velde has entered the following ballot position for
> charter-ietf-opsawg-04-04: No Objection
>
> When responding, please keep the subject line intact and reply to all
> email addresses included in the To and CC lines. (Feel free to cut
> this introductory paragraph, however.)
>
> -------------------------------------------------------------------
> COMMENT:
> -------------------------------------------------------------------
>
> This charter is refreshingly short, clear in its objective, and keeps
> things nice and simple. Just a small comment on the text:
>
> "
> Examples include the advancement of documents on the standards track,
> application statements, maintenance, and minor extensions of documents
> that were developed in working groups that have concluded, e.g.,
> IPFIX, network or service level YANG modules, and tools for the
> Operations and Management Area. "
>
> The word "minor" caught my attention. It might be open to
> interpretation and could lead to debates later on about what qualifies
> as "minor" versus something more substantial. Would it make sense to
> drop that word to avoid any unnecessary restrictions or ambiguity down
> the line?
>
>

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