From owner-freebsd-stable Thu Jun 24 17:41:17 1999 Delivered-To: freebsd-stable@freebsd.org Received: from pop.uniserve.com (pop.uniserve.com [204.244.156.3]) by hub.freebsd.org (Postfix) with SMTP id AA4B314EA7 for ; Thu, 24 Jun 1999 17:41:14 -0700 (PDT) (envelope-from tom@uniserve.com) Received: from shell.uniserve.ca [204.244.186.218] by pop.uniserve.com with smtp (Exim 1.82 #4) id 10xK2n-0004el-00; Thu, 24 Jun 1999 17:40:37 -0700 Date: Thu, 24 Jun 1999 17:40:34 -0700 (PDT) From: Tom X-Sender: tom@shell.uniserve.ca To: Chris Costello Cc: # rm -rf /* , Seth , stable@FreeBSD.ORG Subject: Re: DoS?? In-Reply-To: <19990624190910.C42754@holly.dyndns.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Thu, 24 Jun 1999, Chris Costello wrote: > On Thu, Jun 24, 1999, # rm -rf /* wrote: > > All I can really say is that in the netstat -a.. it was like a syn flood > > except all the connections were established on the ssh port.. we have > > figured out that it just overloads the cpu, bringing the load averages to > > over 500 until it ends.. since ssh has to generate a key, etc.. it takes > > very little to get the load like that.. > > This is already known. Thousands or tens of thousands of ssh > processes are opened up, seriously overloading the CPU. > > It should be deemed classic, and I think there's a way to > limit the maximum amount of connections on that port in > inetd.conf. Using sshd from inetd is just a bad idea. sshd as a daemon is much better, because the key is generated every hour. I belive sshd as a daemon has a max connections settings that you should definitely use. If you must use anything from inetd, use xinetd. xinet can limit connections per service. > -- > Chris Costello > Justify my text? I'm sorry but it has no excuse. > Tom To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message