Scott Harney wrote:

pardon my incredibly sloppy english.  trying to do too many things at once.

> Some of you running ssh on externally reachable have probably noticed 
> numerous attempts in the past few months to log in to various accounts 
> via ssh.  This is apparently a brute force automated attack trying 
> well-known account names, weak passwords, etc.  One way to mitigate this 
> is to make sure you're using strong passwords and changing them with 
> some regularity.  But can you be sure all your users are doing the same?
> 
> If you can, you probably should limited ssh access to specific hosts, 
> but this is often impossible and might not stop determined spoofing 
> attacks.  If you can, you should probably limit ssh authentication to 
> using RSA/DSA keys instead of password-based login.   See 
> http://marc.theaimsgroup.com/?l=openbsd-misc&m=110367957829708&w=2 for 
> info.
> 
> You may still want to block attack attempts, though, and convince 
> automated attack scripts to stop trying.  Some OpenBSD folks posted 
> scripts to check /var/log/authlog for attacks and add those IPs to a pf 
> firewall filter table dynamically.  Not all of my machines with a 
> reachable ssh are OpenBSD but they all run tcp wrappers. So I modified 
> those same scripts to dynamically add attack source IPs to 
> /etc/hosts.deny .  You can find more my script at
> http://www.scottharney.com/blog/2005/01/03#ssh_blocker_wrap-sh
> 
> 


-- 
Scott Harney <[EMAIL PROTECTED]>
"Asking the wrong questions is the leading cause of wrong answers"
gpg key fingerprint=7125 0BD3 8EC4 08D7 321D CEE9 F024 7DA6 0BC7 94E5

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