Through syncing the following entries were added to my hosts.deny:
# DenyHosts: Sun Apr 12 07:00:57 2009 | sshd: 220.127.116.11 (18.104.22.168)
# DenyHosts: Sun Apr 12 07:00:57 2009 | sshd: 22.214.171.124 (126.96.36.199)
and some more of these in subsequent syncs.
They are invalid in the syntax of hosts.deny and give rise to a warning in /var/log/secure when logging into the host through ssh with a valid account and password:
Apr 14 08:12:59 mx1 sshd: warning: /etc/hosts.deny, line 10555: host name/name mismatch: myhost.example.com != some.otherhost.com
where the hosts.deny line refers to the first occurrence of the above quoted illegal entries.
If this means that the hosts.deny file is not parsed further after this illegal entry (there are no warnings in the logs for subsequent ones), this would be a serious security issue.