Re: Attacks on ssh port

From: Willem Jan Withagen (
Date: 09/19/04

  • Next message: Antony Mawer: "Re: Attacks on ssh port"
    Date: Sun, 19 Sep 2004 00:44:33 +0200

    Peter Radcliffe wrote:

    >Willem Jan Withagen <> probably said:
    >>I also have portsentry in a rather sensitive mode doing exactly the same
    >>Trigger one of the "backdoor" ports, and you're out of my game.
    >The general problm with this type of reactive filtering is that if
    >someone can spoof the source addresses effectively or cause a connection
    >from a legitimate host you've just DoSed yourself...
    >Personally I only allow ssh from known legitimate sources and block the
    >rest so the "noise" is in a completely different list.
    I do too, on systems that are completly mine. But I had to "force" this
    customer to refrain from using
    ftp/telnet/... with plain open passwords. And access to this box is
    required from verious remote locations with yet unknown IPs. So I have
    little chances there.

    As far as I know, you need to go thru a lot of trouble to complete a
    spoofed full 3-way handshake just to get my maintenace IP-number blocked.
    Next to the fact that there is a rule before the blocked list which lets
    me in anyways.... :)


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