Permissions Are Too Open

If you SSH to a Linux machine and encounter the following error:

lyle@lyle-laptop:~/Downloads$ ssh -i key-test.pem [email protected]
Permissions 0640 for 'key-test.pem' are too open. It is required that your private key files are NOT accessible by others. This private key will be ignored.

-rw-r----- 1 lyle lyle 1696 Jan 12 14:06 key-test.pem
-rw------- 1 lyle lyle 1771 Jan 23 10:09 key-prod.pem 

Now notice that the permissions for key-test.pem is 640 and the permissions for key-prod.pem is 600

If I was to SSH to a certain box using the key-test.pem it would give me the error above in the first line of this post. If I was to use the key-prod.pem and it is a valid key on that system then it would login without any problems.

To solve this we change the permission of the key file.

lyle@lyle-laptop:~/Downloads$ chmod 600 key-test.pem
Check the permissions

-rw------- 1 lyle lyle 1696 Jan 12 14:06 key-test.pem
-rw------- 1 lyle lyle 1771 Jan 23 10:09 key-prod.pem 

Now you would be able to SSH without any problem.

Just for reference in case you need. A little handy table.

Numeric Value	Permission	Plain English
7	4+2+1	(read/write/execute)
6	4+2	(read/write)
5	4+1	(read/execute)
4	4	(read)
3	2+1	(write/execute)
2	2	(write)
1	1	(execute)