Re: [Debian] Re: [Debian] Re: Undesired ssh login attempts
On Mon, Jun 11, 2018 at 08:04:35AM -0400, Jim Popovitch wrote:
> On Mon, 2018-06-11 at 14:51 +0300, Reco wrote:
> > Hi.
> > On Mon, Jun 11, 2018 at 07:12:32AM -0400, Jim Popovitch wrote:
> > > On Sun, 2018-06-10 at 14:27 +0300, Reco wrote:
> > > >
> > > > Ciphers firstname.lastname@example.org,email@example.com
> > >
> > > What's your thoughts on extending that a bit by adding aes256-ctr
> > > to
> > > that list?
> > Don't use it, unless compatibility with certain Windows SSH clients
> > is
> > required.  is a good read on this Cipher.
> > What I can consider is ADEAD variety of AES, but - I'm uncertain
> > whenever it made its way to OpenSSH at all. It's not in Stretch's
> > version of openssh, that's for sure.
> Hmmm. I was reading  earlier and felt that "Don't use it" applied
> to CBC but not CTR. I use ConnectBot (Android SSH client app) and it
> has a limited set of ciphers.
I have two considerations on this then:
1) Abforementioned link says that (and that applies to aes256-ctr):
* nonce reuse is catastrophic, confidentiality is completely lost
* leaks somewhat more information about the size of the plaintext
Second I can live with, but first is a big "no" in my book.
2) ConnectBot is nice, but I prefer Termux with a proper Debian chroot
That way I'm certain that all the deficiencies/vulnerabilities
discovered in a foreseeable future receive a timely update.