Linux : ssh not working due to wrong key file permission

Problem: ssh not working due to wrong key file permission

In /var/log/messages

Sep 15 05:21:51 localhost sshd[21043]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Sep 15 05:21:51 localhost sshd[21043]: error: @         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
Sep 15 05:21:51 localhost sshd[21043]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Sep 15 05:21:51 localhost sshd[21043]: error: Permissions 0777 for '/etc/ssh/ssh_host_rsa_key' are too open.
Sep 15 05:21:51 localhost sshd[21043]: error: It is required that your private key files are NOT accessible by others.
Sep 15 05:21:51 localhost sshd[21043]: error: This private key will be ignored.
Sep 15 05:21:51 localhost sshd[21043]: error: bad permissions: ignore key: /etc/ssh/ssh_host_rsa_key
Sep 15 05:21:51 localhost sshd[21043]: error: Could not load host key: /etc/ssh/ssh_host_rsa_key

Solution : change the file permission back to read-able by root only