Re: kernel.org status: hints on how to check your machine for intrusion

Steven Rostedt
2011-10-01T18:29:30Z

On Sat, 2011-10-01 at 14:13 -0400, David Miller wrote:
> From: Steven Rostedt <rostedt@goodmis.org>
> Date: Sat, 1 Oct 2011 14:06:41 -0400
>
> > For my machine that is connected to the outside world, I have a script
> > that runs every night that checks for attacks. As bots constantly look
> > for port 22 and 80, they find my machine without issue. When my script
> > detects a bunch of ssh login attempts that fail, it will add that ip
> > address to the iptables DROP chain:
>
> By running sshd on a different port, you'll avoid the login attempts
> as well as the overhead of the successful connection attempts.
>
> I haven't allowed sshd to run on port 22 in more than 10 years.

I use to do that a long time ago, but I ran into issues because of it.
Can't remember the exact problem. Maybe it was places I went to that did
not allow outgoing connections to non official ports. Whatever it was,
it was annoying enough to put sshd back to 22.

I probably can go back to a non 22 port without much issue. I have added
a bunch of personal checks to this box that gives a report every day. I
may add more (from what was posted in this thread already). I also have
logwatch and rkhunter running, and just added chkrootkit now.

But moving the ssh port again may be a good idea. But I like stressing
your net filtering code ;)

-- Steve