Ubuntu server remote file access

[Kent Borg]

On 09/27/2013 11:07 AM, Colin Law wrote:
> I thought that if you used keys for authentication and have disabled 
> password access (as the OP has done), then ssh is effectively unbreakable.

Yes, but now you have shifted the risk to a new location: your private 
ssh key.

How do you protect it?  I hope you have it encrypted, but what if 
someone gets ahold of the encrypted key?  Unlike the sshd which will 
limit how fast one can make attempts, an encrypted file can be put one 
one or more very fast machines and broked far easier.  You had better 
have a lot better passphrase for that encryption, one which it difficult 
to remember and difficult to type blind.

Where do you keep this key file?  How many copies exist?  Have you 
deleted a copy of it?  Can deleted file be un-deleted?

If you have a traditional ssh password the only way to break it is to 
try it against the sshd and it will only let you try so many times a 
second, so much less entropy is needed in your key.


-kb