Server is hung with multiple 'crond' in Red Hat Enterprise Linux

Issue

• There are a lot of CROND processes running

# pstree
init─┬─crond───663*[crond───crond]
     ├─syslog-ng───syslog-ng

# ps -ef | grep CROND | wc -l
1329

root      5135  0.0  0.0   9496  1424 ?        Ss   14:56   0:00 /bin/sh /sbin/service syslog-ng start
root      5142  0.0  0.0  11476  1432 ?        S    14:56   0:00 /bin/sh /etc/init.d/syslog-ng start
root      5155  0.0  0.0  30832  2300 ?        S    14:56   0:00 /opt/syslog-ng/sbin/syslog-ng --no-caps
root      5156  0.0  0.0  30832   888 ?        S    14:56   0:00 supervising syslog-ng
root      5157  0.0  0.0  58484  3244 ?        Ss   14:56   0:00 /opt/syslog-ng/sbin/syslog-ng --no-caps
root      5383  0.0  0.0 148136  1864 ?        S    15:02   0:00 CROND
root      5385  0.0  0.0 148132  1024 ?        S    15:02   0:00 CROND
root      5387  0.0  0.0 148136  1864 ?        S    15:03   0:00 CROND
root      5389  0.0  0.0 148132  1024 ?        S    15:03   0:00 CROND
root      5394  0.0  0.0 148136  1864 ?        S    15:04   0:00 CROND
root      5396  0.0  0.0 148132  1024 ?        S    15:04   0:00 CROND
root      5398  0.0  0.0 148136  1864 ?        S    15:05   0:00 CROND
...

• ping to server is working but ssh from the remote and localhost are not working.
• system logs are not written such as /var/log/messages, /var/log/cron, /var/log/secure