Error message "WARNING: UNPROTECTED PRIVATE KEY FILE!" was printed while connecting through SSH.

Issue

• Can not start sshd service
• Error while connecting through SSH (Putty or Winscp), following errors can be seen in /var/log/messages:

Sep 15 16:25:40 hostname sshd[17397]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Sep 15 16:25:40 hostname sshd[17397]: error: @ WARNING: UNPROTECTED PRIVATE KEY FILE!  @
Sep 15 16:25:40 hostname sshd[17397]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Sep 15 16:25:40 hostname sshd[17397]: error: Permissions 0777 for '/etc/ssh/ssh_host_dsa_key' are too open.
Sep 15 16:25:40 hostname sshd[17397]: error: It is recommended that your private key files are NOT accessible by others.
Sep 15 16:25:40 hostname sshd[17397]: error: This private key will be ignored.
Sep 15 16:25:40 hostname sshd[17397]: error: bad permissions: ignore key: /etc/ssh/ssh_host_dsa_key
Sep 15 16:25:40 hostname sshd[17397]: error: Could not load host key: /etc/ssh/ssh_host_dsa_key
Sep 15 16:25:40 hostname sshd[17397]: Disabling protocol version 2. Could not load host key
Sep 15 16:25:40 hostname sshd[17397]: sshd: no hostkeys available -- exiting.

Aug  7 08:02:15 hostname sshd[30600]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Aug  7 08:02:15 hostname sshd[30600]: error: @         WARNING: UNPROTECTED PRIVATE KEY FILE!          @   
Aug  7 08:02:15 hostname sshd[30600]: error: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Aug  7 08:02:15 hostname sshd[30600]: error: Permissions 0711 for '/etc/ssh/ssh_host_rsa_key' are too open.
Aug  7 08:02:15 hostname sshd[30600]: error: It is recommended that your private key files are NOT accessible by others.
Aug  7 08:02:15 hostname sshd[30600]: error: This private key will be ignored.
Aug  7 08:02:15 hostname sshd[30600]: error: bad permissions: ignore key: /etc/ssh/ssh_host_rsa_key
Aug  7 08:02:16 hostname sshd[30600]: error: Could not load host key: /etc/ssh/ssh_host_rsa_key
Aug  7 08:02:16 hostname sshd[30600]: Disabling protocol version 1. Could not load host key