[Ach] openssh recommendataions: overview of algorithms in different versions

Hanno Böck hanno at hboeck.de
Sun Nov 11 12:53:45 CET 2018


On Sun, 11 Nov 2018 12:31:34 +0100
Sebastian <sebix at sebix.at> wrote:

> to update our recommendations for openssh I collected the supported
> and default settings for Ciphers, MACs and KexAlgorithms of various
> openssh versions. Mostly from manpages.(debian.org|ubuntu.com) and a
> few systems accessible to me.

Here's my recommendation for OpenSSH algorithm security:
Don't touch the default settings.

The OpenSSH developers have been busy aggressively deprecating
everything that looks like fragile crypto over the past couple of
versions. They can do that, because the SSH ecosystem is much less
complex and the average users are more technical. (That doesn't mean it
hasn't caused breakage - I had to tell lots of people to update their
filezilla, putty and what else they use to connect to SSH.)

This is kinda an ideal situation. You don't want people to look up
guides on how to best configure their crypto. You want good defaults.
This is difficult in the TLS space, because compatibility
considerations are complex and upstream projects are slow to adopt. But
with OpenSSH this is happening and the defaults are good. Don't tell
people to use anything else as long as they don't have very good
reasons for it.

Hanno Böck

mail/jabber: hanno at hboeck.de
GPG: FE73757FA60E4E21B937579FA5880072BBB51E42
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