To remediate the misconfiguration of having an EC2 instance in a public subnet in AWS using AWS CLI, follow these steps:

1. Identify the public subnet in which the EC2 instance is running. You can do this by checking the subnet’s route table and confirming that it has a route to an Internet Gateway.

2. Create a new private subnet in the same VPC as the public subnet. This new subnet should have a non-overlapping CIDR block and should not have a route to an Internet Gateway.

3. Stop the EC2 instance that is running in the public subnet.

4. Modify the instance’s network interface to move it from the public subnet to the new private subnet. You can do this using the following command:

aws ec2 modify-network-interface-attribute --network-interface-id <network-interface-id> --subnet-id <new-private-subnet-id>

Replace <network-interface-id> with the ID of the network interface attached to the EC2 instance, and <new-private-subnet-id> with the ID of the new private subnet you created.

5. Start the EC2 instance.

6. Verify that the EC2 instance now has a private IP address in the new private subnet and does not have a public IP address. You can do this by checking the instance’s network interface settings.

To remediate the misconfiguration of an EC2 instance in a public subnet in AWS using Python, you can follow the below steps:

1. First, you need to identify the EC2 instances that are in the public subnet. You can do this by using the describe_instances method of the boto3 library in Python.

import boto3

ec2 = boto3.client('ec2')

response = ec2.describe_instances(
    Filters=[
        {
            'Name': 'subnet-id',
            'Values': [
                'subnet-0123456789abcdef0',
            ]
        },
    ]
)

for reservation in response['Reservations']:
    for instance in reservation['Instances']:
        print(instance['InstanceId'])

Replace the subnet-id with the ID of the public subnet.

2. Once you have identified the instances, you need to move them to a private subnet. To do this, you can modify the network interface of the instance and attach it to a private subnet. You can use the modify_network_interface_attribute method of the boto3 library to do this.

import boto3

ec2 = boto3.client('ec2')

response = ec2.modify_network_interface_attribute(
    NetworkInterfaceId='eni-0123456789abcdef0',
    Groups=[
        'sg-0123456789abcdef0',
    ],
    Description={
        'Value': 'Modified description'
    }
)

print(response)

Replace the NetworkInterfaceId with the ID of the network interface of the instance that you want to modify. Also, replace the sg-0123456789abcdef0 with the ID of the security group that you want to attach to the network interface.

3. After modifying the network interface, you need to verify that the instance is now in the private subnet. You can do this by checking the SubnetId attribute of the instance using the describe_instances method.

import boto3

ec2 = boto3.client('ec2')

response = ec2.describe_instances(
    InstanceIds=[
        'i-0123456789abcdef0',
    ],
)

for reservation in response['Reservations']:
    for instance in reservation['Instances']:
        print(instance['SubnetId'])

Replace the i-0123456789abcdef0 with the ID of the instance that you want to check.

By following these steps, you can remediate the misconfiguration of an EC2 instance in a public subnet in AWS using Python.