sshd[29286]: Bad protocol version identification '0' from 127.0.0.1

Just wondering if anyone knows what could be causing this error message
in the sshd logs:

$ sudo grep 'Bad protocol' /var/log/auth.log
Nov 7 00:48:32 starke sshd[29286]: Bad protocol version identification
'0' from 127.0.0.1
Nov 7 02:33:11 starke sshd[31438]: Bad protocol version identification
'0' from 127.0.0.1
Nov 7 02:49:53 starke sshd[14860]: Bad protocol version identification
'0' from 127.0.0.1
Nov 7 03:19:41 starke sshd[12458]: Bad protocol version identification
'0' from 127.0.0.1
Nov 7 03:19:57 starke sshd[12534]: Bad protocol version identification
'0' from 127.0.0.1
Nov 7 05:19:35 starke sshd[20021]: Bad protocol version identification
'0' from 127.0.0.1

The only reference i found to this on google was a local exploit in
logwatch http://www.securiteam.com/exploits/5SP032A6US.html
from 2002 but I am not running logwatch but am using logcheck on debian
sarge.

Using telnet I checked out how I could reproduce it and by telneting
over ssh from the localhost and just typing 0 once connected I get the
same error message. I have no idea what would be doing that though and
whether or not it could be someone attempting and exploit.
$telnet localhost 22
$tail -f /var/log/auth.log
Nov 7 08:57:21 starke sshd[4796]: Bad protocol version identification
'0' from 127.0.0.1

Thanks for any help

John
The last line was