You are trying to connect to a running EC2 instance using SSH. However, you are receiving an “Unprotected Private Key File” error. What is the possible root cause of this issue?

Answer options:

A.Your IAM Role does not have sufficient permissions.
B.The private key file has the wrong file permissions.
C.The public key file has the wrong permissions.
D.The KMS CMK key policy has the wrong permissions.

Answer: B
Option A is incorrect because the IAM role assigned to the user is not related to logging into EC2 instances using SSH.
Option B is CORRECT because your private key file must be protected from read and write operations from any other users.
Option C is incorrect because the issue is with the private key. Hence, solving permissions on the public key would not provide the solution to the error.
Option D is incorrect because KMS is not used to manage user public-key pairs for EC2 instances.
To fix the error, execute the following command and substitute the path for your private key file.
chmod 0400 .ssh/.pem
Reference:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html#troubleshoot-unprotected-key