[CentOS] SSH attacks from china
Miguel Medalha
miguelmedalha at sapo.pt
Fri Jul 24 16:07:29 UTC 2009
>> Using a non default port is not the solution, because history has learned
>> that security by obscurity never worked.....
>>
>
> It's not "security by obscurity", moving the default port is just to not
> see all that garbage in the log files - as the automated scripts don't
> check for ssh on different ports than 22.
>
People get those fixed ideas and it is difficult to get rid of them. Of
course you should not rely ONLY on obscurity to secure your server. But
using a non-standard port effectively defeats *the vast majority* of
attacks, which never try other than the standard port. I went from
thousands of entries in the logs to NONE.
> And save cpu cycles by not having to answer to those requests.
>
>
YES!
>> 1: Use Iptables or other firewall in front of server, to only allow a
>> selected group of "trusted" Ip's to access the server trough SSH.
>>
>
> Well, that is not always possible or wanted.
>
>
Of course! In my case it is not even possible.
>> 2: Enforce Public / Private key Authentication, so that only the users with
>> a valid key can access the server.
>>
>
> And yes, you shouldn't be using ssh with password authentication, true.
>
>
Yes! Use only authentication with an encrypted key, e.g. a
public/private key pair.
More information about the CentOS
mailing list