allow-temp-ec2-access-only.json

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "ssm:StartSession"
            ],
            "Resource": [
                "arn:aws:ec2:*:*:instance/i-*",
                "arn:aws:ssm:[region]:[acc-num]:document/SSM-SessionManagerRunShell",
                "arn:aws:ssm:*:*:document/AWS-StartPortForwardingSession"
            ],
            "Condition": {
                "BoolIfExists": {
                    "ssm:SessionDocumentAccessCheck": "true"
                }
            }
        },
        {
            "Effect": "Allow",
            "Action": [
                "ssm:DescribeSessions",
                "ssm:GetConnectionStatus",
                "ssm:DescribeInstanceProperties",
                "ec2:DescribeInstances"
            ],
            "Resource": "[instance-ID]"
        },
        {
            "Effect": "Allow",
            "Action": [
                "ssm:TerminateSession"
            ],
            "Resource": [
                "arn:aws:ssm:*:*:session/${aws:username}-*"
            ]
        }
    ]
}