Webmail?

Fri Jul 6 09:25:48 PDT 2018

*Convergence* was a proposed strategy for replacing SSL
<https://en.m.wikipedia.org/wiki/Secure_Sockets_Layer> certificate
authorities <https://en.m.wikipedia.org/wiki/Certificate_authority>, first
put forth by Moxie Marlinspike
<https://en.m.wikipedia.org/wiki/Moxie_Marlinspike> in August 2011 while
giving a talk titled "SSL and the Future of Authenticity" at the Black Hat
security conference <https://en.m.wikipedia.org/wiki/Black_Hat_Briefings>.
[1] <https://en.m.wikipedia.org/wiki/Convergence_%28SSL%29#cite_note-1> It
was demonstrated with a Firefox addon
<https://en.m.wikipedia.org/wiki/Firefox_addon> and a server-side notary
daemon <https://en.m.wikipedia.org/wiki/Daemon_%28computing%29>.

https://en.m.wikipedia.org/wiki/Convergence_(SSL)

On Wed, Jul 4, 2018, 5:01 PM Zenaan Harkness <zen at freedbms.net> wrote:

> Snake oil to the rescue...
>
>
> ----- Forwarded message from Zenaan Harkness <zenaan at freedbms.net> -----
>
> From: Zenaan Harkness <zenaan at freedbms.net>
> To: debian-user at lists.debian.org
> Date: Mon, 2 Jul 2018 11:11:13 +1000
> Subject: Re: Webmail?
>
> On Sun, Jul 01, 2018 at 10:40:13PM +1200, Richard Hector wrote:
> > On 01/07/18 21:57, Zenaan Harkness wrote:
> > >> Oh, use https:// and make sure any security is activated in conf.pl.
> >
> > > And with your self-issued snake oil certs, make sure you check and
> > > confirm the cert on each device you want to use to access your
> > > webmail server, from your home network, so that if you eventually
> > > tunnel in or otherwise access it 'on the road', you have already
> > > verified your own snake oil cert and a MITM should stand out like
> > > unicorn balls.
> >
> > For any server on the internet, I don't see the point in using
> > self-signed certs any more, now that letsencrypt gives you real ones for
> > free.
>
> Only a -true- Scotsman would self sign and issue his own SSL certs :)
>
> I believe it's degrees of snake oil...
>
>
> > It's a bit more of a pain for a server that's only accessed internally,
> > but still doable, if you can set up a dummy site for verification (there
> > are ways to do it without a web server, but I haven't needed that yet)
>
> It's actually a bit of an open question, but the real question is
> "what level of security do you actually need or want?" … of course.
>
> Consider e.g.:
>
>  - how to conduct an MITM?
>   - get a copy of private key, issue additional cert
>   - get private key, issue intermediate cert
>   - get intermediate cert key, issue other intermediate certs
>
>  - is an MITM of concern to you?
>   - I do/don't care if the govt has open access to my certs,
>     and can/can't MITM my users
>   - I do/don't care if Random J Cracker can MITM my telecommuting
>     co-workers
>
> Most of us by now will have read at least one article about the CIA
> and NSA's cornucopia of network cracking tools, bugs, physical
> network bugs and "rogue" hosts hosted at every host hoster worth his
> hosting salt - google, amazon, your local ISP, etc - oh, and "by
> consent, possibly with $ inducement and implied threat of legal
> sanction for failure to 'co-operate' with said inducement".
>
> But again, what level of security do you need?
>
>  ∙ If you want minimum pain web servers accessible to the public,
>   providing "basic trust level", then LetsEncrypt is likely your
>   best approach.
>
>  ∙ If you don't have "general public access" as a requirement, and
>   you are willing to double check each device accessing your local
>   network to ensure they've each pre-loaded your internal-only web
>   server cert, then your own PKI and self signed certs may give you
>   higher security (barring catastrophic mistakes on your part), and
>   certainly more control.
>
>   In this scenario, if you don't need control over the private keys
>   to your electronic kingdom - by all means, use a commercial or
>   free provider, and LetsEncrypt is perhaps about as good as it
>   gets.
>
>   For those after a higher level of certainty and control however,
>   there is no substitute to offline master key generation and
>   storage, private PKI and total in-house control over all
>   sub-keys/sub-certs, issuances, revocations and per-device key
>   signature double checking.
>
> If you want anything even resembling certainty that is...
>
>
> Here's a true fist hand anecdote:
>
>  A few years ago, I was setting up a VM and some basic web services
>  for a client with a top tier 'reputable' provider - one of the
>  largest in Australia, at least at the time.
>
>  When connecting via ssh for the first time, the usual "This is a new
>  host, here's the sig, do you confirm this is the correct signature"
>  type message came up.
>
>  So I check the time and it's well after peak hour (about 11pm), and
>  quickly dial their 24-hour tech support line, asking for someone to
>  please check the host signature (this was virtual hosting, just
>  before VMs took off), so as to preclude any superficial MITM
>  swankery.
>
>  The tech says to me "Um, I'm not sure about that, I've never been
>  asked that question before," and promptly bumps it up to a deep tech
>  PoC (person of competency), who double checks the host SSH sig hash
>  from their internal network, confirms it's correct, then he too says
>  "you know, as far as I'm aware, in over 15 years, this is the first
>  time, ever, that any client has ever asked us to confirm their end
>  to end encryption/ signature!" I confirmed that he had in fact
>  worked at the company since it began.
>
>
> And most important - if you intend to configure your own PKI for
> "increased security" purposes, note that you really need to make sure
> you use certificate pinning for your own org's certs, or disable the
> other CAs "by default trusted" by your client OS browsers! - The easy
> way is use a Firefox profile for your company/ internal websites/
> VPN/ telecommuters and make sure only your CA is the trusted root in
> that profile! (and make sure that your internal web sites can only be
> accessed from that profile) :
>
>  Are self-signed certificates actually more secure than CA
>  signed certificates now?
>
> https://security.stackexchange.com/questions/42409/are-self-signed-certificates-actually-more-secure-than-ca-signed-certificates-no
>
>
>
> See also:
>
> 4 fatal problems with PKI
>
> https://www.csoonline.com/article/2942072/security/4-fatal-problems-with-pki.html
>
> SSL certificate revocation and how it is broken in practice
>
> https://medium.com/@alexeysamoshkin/how-ssl-certificate-revocation-is-broken-in-practice-af3b63b9cb3
>
> When are self-signed certificates acceptable for businesses?
>
> https://www.techrepublic.com/article/when-are-self-signed-certificates-acceptable-for-businesses/
>
> Good luck :)
>
>
> ----- End forwarded message -----
>
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