unprotected private key file

I would recommend you to re create a set of keys using

ssh-keygen -t rsa -C '<email>'

for a more secure system. Else changing the permissions to something less open would do.

To change permissions, use

chmod  400 ~/.ssh/id_rsa

Simply reset permissions to your key files to defaults

sudo chmod 600 ~/.ssh/id_rsa
sudo chmod 600 ~/.ssh/id_rsa.pub

Just change the permission of the /.ssh/id_rsa file to 400

#chmod  400 ~/.ssh/id_rsa

This won't make others or from any group members to modify the file.