Here is what a ssh bruteforce attack looks like from a cisco router log
uthentication Failed] at 01:13:18 UTC Sun Sep 30 2012
*Sep 30 01:13:18.463: %SEC_LOGIN-1-QUIET_MODE_ON: Still timeleft for watching failures is 0 secs, [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] [ACL: 100] at 01:13:18 UTC Sun Sep 30 2012
*Sep 30 01:13:24.967: %SEC_LOGIN-4-LOGIN_FAILED: Login failed [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] at 01:13:24 UTC Sun Sep 30 2012
*Sep 30 01:13:24.967: %SEC_LOGIN-1-QUIET_MODE_ON: Still timeleft for watching failures is 0 secs, [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] [ACL: 100] at 01:13:24 UTC Sun Sep 30 2012
*Sep 30 01:13:31.447: %SEC_LOGIN-4-LOGIN_FAILED: Login failed [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] at 01:13:31 UTC Sun Sep 30 2012
*Sep 30 01:13:31.447: %SEC_LOGIN-1-QUIET_MODE_ON: Still timeleft for watching failures is 0 secs, [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] [ACL: 100] at 01:13:31 UTC Sun Sep 30 2012
*Sep 30 01:13:37.963: %SEC_LOGIN-4-LOGIN_FAILED: Login failed [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] at 01:13:37 UTC Sun Sep 30 2012
*Sep 30 01:13:37.963: %SEC_LOGIN-1-QUIET_MODE_ON: Still timeleft for watching failures is 0 secs, [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] [ACL: 100] at 01:13:37 UTC Sun Sep 30 2012
*Sep 30 01:13:44.307: %SEC_LOGIN-4-LOGIN_FAILED: Login failed [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] at 01:13:44 UTC Sun Sep 30 2012
*Sep 30 01:13:44.307: %SEC_LOGIN-1-QUIET_MODE_ON: Still timeleft for watching failures is 0 secs, [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] [ACL: 100] at 01:13:44 UTC Sun Sep 30 2012
*Sep 30 01:13:50.771: %SEC_LOGIN-4-LOGIN_FAILED: Login failed [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] at 01:13:50 UTC Sun Sep 30 2012
*Sep 30 01:13:50.771: %SEC_LOGIN-1-QUIET_MODE_ON: Still timeleft for watching failures is 0 secs, [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] [ACL: 100] at 01:13:50 UTC Sun Sep 30 2012
*Sep 30 01:13:57.239: %SEC_LOGIN-4-LOGIN_FAILED: Login failed [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] at 01:13:57 UTC Sun Sep 30 2012
*Sep 30 01:13:57.239: %SEC_LOGIN-1-QUIET_MODE_ON: Still timeleft for watching failures is 0 secs, [user: root] [Source: 211.144.68.163] [localport: 22] [Reason: Login Authentication Failed] [ACL: 100] at 01:13:57 UTC Sun Sep 30 2012
The above shows a perfect example why you should have a radiius server or tacas server for authentication with an ip ban mechanism this prevents scripts such as the above one from constantly trying to bruteforce attack your edge router from the same ip which would force the script to either use a different proxy or change servers not a total solution but an effective layer of security you can also use things like vpn so an administrator would vpn into your local network and then locally access your equipment
Just a little tid bit of knowledge
Till next time
Stay secure !