Cisco WLC interface and cli are extremely slow

Today I encountered a case when one of 5500 Cisco wireless controllers stopped operating properly. Both GUI and ssh were extremely slow and users complained too.
In the logs I could see multiple unsaccessfull authentications. Below is how it looked like.
Appeared that local IT guy connected WLC console to a local cisco router. Looped router console output was treated as an authentication attempt.

242    Fri Apr 4 06:39:28 2014    User Usage is monitored; unauthorized from CONSOLE has made too many unsuccessful login attempts.
244    Fri Apr 4 06:39:06 2014    User User Access Verification from CONSOLE has made too many unsuccessful login attempts.