Folks,

I'm posting this in the awareness that there's probably nothing to be
done about it at this stage, but some forensic advice might help:

My Ubuntu Hardy (8.04) server is hosted by a crowd who cut costs by not
providing remote console access or remote power control. It runs OSSEC
1.6 with the only major configuration tweak being an increase in the
active response window: firewall lockouts last for 24 hours rather than
five minutes because otherwise the barbarian hordes keep my load average
permanently around 3 (on a single-CPU x86). Server has been up for a few
weeks withou incident, no significant outages in >12 months.

This morning I logged in to turn down the level of the Postfix 'multiple
delivery attempts from a blacklisted IP' alert from 10 to 8. I made the
change and restarted ossec.

Almost immediately, the process table began to fill with 'iptables' and
'host-deny' processes, and load shot up over 100 within a few seconds.

I am now completely locked out: ssh connections time out. I can ping the
machine, but that's all. 

To my chagrin, I have used up my free support tickets for the month, so
I will have to pay cash to have my server physically rebooted. I am
hesitating only because I have no way of knowing if this will fix the
problem.

Can anyone suggest what may have just happened? I need to make sure this
can't ever happen again, even if that involves removing ossec: Not even
ossec can be allowed to thrash the machine so hard that ssh connectivity
goes down.

--
Thorne Lawler
Technical Consultant
Managed Services | Infrastructure Services | Server Support Unix | KAZ
Group Pty Ltd
360 Elizabeth Street | Melbourne Victoria 3000
(03) 9631 1747 | 0408 491 552 | Fax: (03) 9654 7334
[EMAIL PROTECTED] | www.kaz-group.com
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