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