[CentOS] Paranoid Firewalling
t004 at kbocek.com
Wed Sep 7 01:08:28 UTC 2005
No! It's my secret! Bu-Wa-Ha-Ha! (or however that's spelled...)
Okay, you forced it out of me...
Sam Drinkard wrote:
> If you don't mind, could you let me know where that script is? I'm
> seeing the same thing -- kiddies trying to log in. I use something
> similar, but manual entry on my mail server that is in a co-lo site
> running FreeBSD. Here at home, I thought I'd be pretty well protected
> behind the router, but I have to have the ssh port open, and I'm seeing
> hundreds of attempts.
> Kirk Bocek wrote:
>> Good question Alex. However, I've never studied the scripts that
>> 'script kiddies' use and so have no answer.
>> Part of what has prompted this change is the recent surge of
>> brute-force password attacks. From the timing of the password
>> attempts, it's clear that these are script driven.
>> I found a perl script that watches for failed logins. After a
>> configurable number, the script enters the IP address into
>> /etc/hosts.deny. After a configurable number of days, the script then
>> removes the IP address.
>> What I see in /var/log/secure is a whole series of 'Invalid user'
>> messages followed by 'Failed password for invalid user' messages.
>> These will then, because of the script, be terminated by a 'refused
>> connect from' message when the address is entered into hosts.deny.
>> My point in all this is that I only ever see *one* 'refused connect'
>> message. So at least for this script, it gives up when it can't
>> connect anymore.
>> Kirk Bocek
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