SSH attacks - anyone else seen these?

[Tim <secnews () sp1r1t de>]

I've recently noticed this in my logs: 

Oct 15 15:30:04 mysrv sshd[9563]: Bad protocol version 
identification 'POST /unauthenticated//..%01/..%01/..%01/..%01/..%01/..%01/..
%01/..%01/..%01/..%01/..%01/..%01/..%01' from 59.106.20.158

Oct  1 17:14:51 mysrv sshd[9915]: Bad protocol version 
identification '\377\364\377\375\006\377\364\377\375\006\377\364\377\375\006' 
from 84.58.87.123
Oct  1 17:15:13 airrocket sshd[11982]: Bad protocol version identification '' 
from 84.58.87.123

Did anyone else notice similar things? Does anyone know what vulnerability 
they are attacking?

Thanks,

-- 
Tim