BF: filter.d/sshd "Did not receive identification string" relates to an exploit so document this in sshd-ddos.conf but leave it out of authentication based blocks in sshd.conf

config/filter.d/sshd-ddos.conf

@@ -2,6 +2,13 @@
 #
 # Author: Yaroslav Halchenko
 #
+# The regex here also relates to a exploit:
+#
+#  http://www.securityfocus.com/bid/17958/exploit
+#  The example code here shows the pushing of the exploit straight after
+#  reading the server version. This is where the client version string normally
+#  pushed. As such the server will read this unparsible information as
+#  "Did not receive identification string".
 
 [INCLUDES]
 

config/filter.d/sshd.conf

@@ -24,7 +24,6 @@ _daemon = sshd
 # Values:  TEXT
 #
 failregex = ^%(__prefix_line)s(?:error: PAM: )?Authentication failure for .* from <HOST>\s*$
-            ^%(__prefix_line)sDid not receive identification string from <HOST>$
             ^%(__prefix_line)s(?:error: PAM: )?User not known to the underlying authentication module for .* from <HOST>\s*$
             ^%(__prefix_line)sFailed \S+ for .* from <HOST>(?: port \d*)?(?: ssh\d*)?\s*$
             ^%(__prefix_line)sROOT LOGIN REFUSED.* FROM <HOST>\s*$