Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

SSH client audit #10

Open
knweiss opened this issue Oct 14, 2016 · 5 comments
Open

SSH client audit #10

knweiss opened this issue Oct 14, 2016 · 5 comments

Comments

@knweiss
Copy link

knweiss commented Oct 14, 2016

What do you think about the idea of a SSH client audit feature?

Of course, admins can configure a good and up-to-date system-wide client config (/etc/ssh/ssh_config). However, users also have their own (and often ancient!) settings in ~/.ssh/config. AFAIK there is no tool that audits the client settings and gives recommendations.

When I discovered the ssh -G host option (available since OpenSSH 6.8) I thought this may be an interesting and easy way to audit the effective client settings for the respective destination.

Also, it would be possible to not only check the configured algorithms but also insecure or dangerous features (e.g. X11Forwarding, Agent-Forwarding, etc).

It could look like this:

$ ssh-audit -c host
@knweiss
Copy link
Author

knweiss commented Oct 14, 2016

Also, checking the bit sizes of the configured SSH user keys (e.g. RSA >= 2048 bit) would be another useful client-side check.

@knweiss
Copy link
Author

knweiss commented Oct 17, 2016

Or checking the (new) storage format of the private key (bcrypt KDF and number of rounds) or the public key (RFC 4716).

Or warning about the key age and hinting about key rotation if the local private key file has an old timestamp.

@egberts
Copy link

egberts commented Oct 20, 2017

:thumbup:

@jtesta
Copy link

jtesta commented Nov 14, 2019

@knweiss @egberts I implemented SSH client testing in v2.1.0 of my fork: https://github.com/jtesta/ssh-audit/releases/tag/v2.1.0

@egberts
Copy link

egberts commented Nov 19, 2019

Oh, and please do check for those pesky "ControlMaster" settings. It is getting problematic. A minimum warning message there.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

3 participants