The Security Group Changes Alarm is triggered when a security group in your AWS account is modified. To remediate this issue, you can follow the below steps using AWS CLI:

1. Firstly, identify the security group that is being modified. You can do this by checking the CloudWatch logs for the Security Group Changes Alarm.

2. Once you have identified the security group, review the changes that were made to the security group. This can be done by checking the security group’s inbound and outbound rules.

3. If the changes were made intentionally, you can update the Security Group Changes Alarm to ignore these changes in the future. To do this, you can modify the CloudFormation stack that created the Security Group Changes Alarm.

4. If the changes were made unintentionally, you should revert the security group to its previous configuration. To do this, you can use the AWS CLI command aws ec2 revoke-security-group-ingress to remove any newly added inbound rules, and aws ec2 revoke-security-group-egress to remove any newly added outbound rules.

5. After reverting the security group to its previous configuration, you should update the Security Group Changes Alarm to ensure that it is triggered if any further changes are made to the security group.

6. Finally, you should investigate the cause of the security group changes and take any necessary steps to prevent similar misconfigurations in the future.

To remediate the “Security Group Changes Alarm” misconfiguration in AWS using Python, you can follow the below steps:

1. Identify the security group that triggered the alarm. You can find this information in the CloudWatch alarm details.

2. Check the security group rules to see if any unauthorized changes were made. You can use the describe_security_groups() method from the Boto3 library to retrieve the security group rules.

3. If any unauthorized changes were made, revert them by calling the revoke_security_group_ingress() or revoke_security_group_egress() method from the Boto3 library. You will need to provide the appropriate parameters such as the security group ID, IP permissions, etc.

4. Once the changes have been reverted, update the CloudWatch alarm status to “OK” using the set_alarm_state() method from the Boto3 library.

Here’s an example Python code snippet that demonstrates how to remediate the “Security Group Changes Alarm” misconfiguration:

import boto3

# Initialize the Boto3 client
ec2 = boto3.client('ec2')

# Specify the security group ID that triggered the alarm
security_group_id = 'sg-0123456789abcdef'

# Retrieve the security group rules
response = ec2.describe_security_groups(GroupIds=[security_group_id])

# Check if any unauthorized changes were made
# If yes, revert the changes
for sg in response['SecurityGroups']:
    for ip_perm in sg['IpPermissions']:
        if 'YOUR_UNAUTHORIZED_IP_RANGE' in ip_perm['IpRanges']:
            ec2.revoke_security_group_ingress(
                GroupId=security_group_id,
                IpPermissions=[ip_perm]
            )

# Update the CloudWatch alarm status to "OK"
cloudwatch = boto3.client('cloudwatch')
cloudwatch.set_alarm_state(
    AlarmName='YOUR_ALARM_NAME',
    StateValue='OK',
    StateReason='Misconfiguration has been remediated'
)

Note: Replace YOUR_UNAUTHORIZED_IP_RANGE, YOUR_ALARM_NAME and sg-0123456789abcdef with the appropriate values specific to your environment.