mikrotik attack?

RouterOS General
1

i open a new terminal. i see a list of critical login failures.
is this some kind of attack? see below

jan/17/2011 08:27:51 system,error,critical login failure for user root from 140.52.115.30 via ssh
jan/17/2011 08:27:55 system,error,critical login failure for user root from 140.52.115.30 via ssh
jan/17/2011 08:28:00 system,error,critical login failure for user root from 140.52.115.30 via ssh
jan/17/2011 08:28:03 system,error,critical login failure for user root from 140.52.115.30 via ssh
jan/17/2011 08:28:12 system,error,critical login failure for user root from 140.52.115.30 via ssh
jan/17/2011 08:28:17 system,error,critical login failure for user root from 140.52.115.30 via ssh
jan/17/2011 08:28:20 system,error,critical login failure for user oracle from 140.52.115.30 via ssh
jan/17/2011 08:28:24 system,error,critical login failure for user test from 140.52.115.30 via ssh

2

ssh bruteforce attack, close ssh port or use firewall or change port number

3

This is a good solution against this attack:
http://wiki.mikrotik.com/wiki/Bruteforce_login_prevention

4

thanks…

thanks…normis