Messages in this thread | | | Date | Sat, 1 Oct 2011 14:06:41 -0400 | From | Steven Rostedt <> | Subject | Re: kernel.org status: hints on how to check your machine for intrusion |
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On Sat, Oct 01, 2011 at 09:35:33AM +0200, Willy Tarreau wrote: > > - last considerations to keep in mind is that machines which receive > incoming connections from outside should never be able to go out, and > should be isolated in their own LAN. It's not hard to do at all, and > it massively limits the ability to bounce between systems and to steal > information. It also makes firewall logs much more meaningful, provided > they are stored on a support with limited access, of course :-)
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:
# iptables -L -n | grep DROP | wc -l 2656
I've picked up quite a few ;)
This script only runs and scans once at night. Probably better to have it run more often.
If any one is interested in this simple script, I can send it to them. I'd have to audit it to make sure that it doesn't expose anything else that may be of security to me (other machine IPs that I don't want public, etc).
-- Steve
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