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Event Information

  • The CreateRouteTable event in AWS for EC2 refers to the action of creating a route table within a Virtual Private Cloud (VPC) in the AWS environment.
  • A route table is a set of rules, known as routes, that determine where network traffic is directed within a VPC. It acts as a virtual router, allowing traffic to flow between subnets and to external networks.
  • When the CreateRouteTable event occurs, it means that a new route table has been created, and it can be associated with one or more subnets to control the traffic flow within the VPC.

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Examples

  • Misconfiguration of route table permissions: If the permissions for the route table are not properly configured, it can lead to unauthorized access or modification of the routes, potentially compromising the security of the network.

  • Insecure routing: If the routes in the route table are not properly configured, it can result in traffic being routed through insecure or unauthorized paths, potentially exposing sensitive data or resources to unauthorized access.

  • Lack of network segmentation: If the route table is not properly segmented, it can result in different types of traffic being mixed together, potentially increasing the attack surface and making it easier for an attacker to move laterally within the network.

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Remediation

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Using Console

  1. Example 1: Unauthorized Access to AWS EC2 Instance

    • Step 1: Identify the compromised EC2 instance by reviewing the event logs or security alerts.
    • Step 2: Terminate the compromised EC2 instance to prevent further unauthorized access.
    • Step 3: Launch a new EC2 instance with the latest AMI and apply necessary security configurations, such as disabling unnecessary ports, implementing strong access controls, and enabling encryption.

  2. Example 2: Unusual Network Traffic from AWS EC2 Instance

    • Step 1: Analyze the network traffic logs or security alerts to identify the source and destination of the unusual traffic.
    • Step 2: Disable or block the suspicious network traffic by modifying the security group rules associated with the affected EC2 instance.
    • Step 3: Implement additional security measures, such as enabling VPC flow logs, configuring network ACLs, or using a web application firewall (WAF) to protect against future network-based attacks.

  3. Example 3: Unauthorized API Calls from AWS EC2 Instance

    • Step 1: Review the CloudTrail logs or security alerts to identify the unauthorized API calls and the affected EC2 instance.
    • Step 2: Revoke the IAM credentials associated with the compromised EC2 instance to prevent further unauthorized API calls.
    • Step 3: Implement least privilege access control by creating a new IAM role or user with only the necessary permissions for the EC2 instance, and update the instance with the new credentials. Additionally, consider enabling multi-factor authentication (MFA) for IAM users to enhance security.

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Using CLI

  1. Ensure that all EC2 instances are using the latest Amazon Machine Images (AMIs) by regularly checking for updates and patching any vulnerabilities. Use the following AWS CLI commands:

    • List all available AMIs: aws ec2 describe-images
    • Identify the latest AMI version for your desired operating system
    • Update the EC2 instance with the latest AMI: aws ec2 run-instances --image-id <AMI_ID> --instance-type <INSTANCE_TYPE>

  2. Implement security groups to control inbound and outbound traffic to your EC2 instances. Use the following AWS CLI commands:

    • Create a security group: aws ec2 create-security-group --group-name <GROUP_NAME> --description <DESCRIPTION>
    • Configure inbound rules to allow necessary traffic: aws ec2 authorize-security-group-ingress --group-id <GROUP_ID> --protocol <PROTOCOL> --port <PORT> --cidr <CIDR>
    • Configure outbound rules to restrict unnecessary traffic: aws ec2 authorize-security-group-egress --group-id <GROUP_ID> --protocol <PROTOCOL> --port <PORT> --cidr <CIDR>

  3. Enable AWS CloudTrail to monitor and log all API activity within your AWS account. Use the following AWS CLI commands:

    • Create a new S3 bucket to store CloudTrail logs: aws s3api create-bucket --bucket <BUCKET_NAME> --region <REGION>
    • Enable CloudTrail for your AWS account: aws cloudtrail create-trail --name <TRAIL_NAME> --s3-bucket-name <BUCKET_NAME>
    • Start logging API activity: aws cloudtrail start-logging --name <TRAIL_NAME>

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Using Python

  1. Example 1: Enforce secure communication for AWS EC2 instances using SSL/TLS:

    • Generate an SSL/TLS certificate for the EC2 instance using a certificate authority or a self-signed certificate.
    • Install the certificate on the EC2 instance and configure the web server or application to use SSL/TLS.
    • Update the security group rules to allow inbound traffic on the appropriate SSL/TLS port (e.g., 443 for HTTPS).

    Python script example:

    # Install required packages
import subprocess
subprocess.call(['pip', 'install', 'certbot'])

# Generate SSL/TLS certificate using Certbot
subprocess.call(['certbot', 'certonly', '--standalone', '-d', 'example.com'])

# Install the certificate on the EC2 instance
# (Steps may vary depending on the web server or application being used)

  2. Example 2: Enable encryption at rest for AWS EC2 EBS volumes:

    • Create a new AWS Key Management Service (KMS) customer master key (CMK) or use an existing one.
    • Enable encryption for the EBS volumes by specifying the CMK during volume creation or by modifying the existing volumes.
    • Update the relevant IAM policies to ensure appropriate access to the CMK for encryption and decryption operations.

    Python script example:

    import boto3

# Create a new CMK or use an existing one
kms_client = boto3.client('kms')
response = kms_client.create_key()

# Enable encryption for the EBS volumes
ec2_client = boto3.client('ec2')
response = ec2_client.modify_volume(
    VolumeId='vol-1234567890abcdef0',
    Encrypted=True,
    KmsKeyId='arn:aws:kms:us-east-1:123456789012:key/abcd1234-5678-90ab-cdef-1234567890ab'
)

# Update IAM policies to grant appropriate access to the CMK

  3. Example 3: Implement AWS EC2 instance backups using Amazon EBS snapshots:

    • Create an Amazon CloudWatch Events rule to trigger a Lambda function on a scheduled basis.
    • Write a Lambda function in Python to create EBS snapshots of the desired EC2 instances.
    • Configure the Lambda function to tag the snapshots with relevant metadata for easy identification and management.

    Python script example:

    import boto3
import datetime

def lambda_handler(event, context):
    ec2_client = boto3.client('ec2')
    response = ec2_client.describe_instances(
        Filters=[
            {'Name': 'tag:Backup', 'Values': ['true']}
        ]
    )

    for reservation in response['Reservations']:
        for instance in reservation['Instances']:
            instance_id = instance['InstanceId']
            snapshot_description = f"Backup for instance {instance_id} on {datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')}"

            response = ec2_client.create_snapshot(
                Description=snapshot_description,
                VolumeId=instance['BlockDeviceMappings'][0]['Ebs']['VolumeId']
            )

            snapshot_id = response['SnapshotId']
            ec2_client.create_tags(
                Resources=[snapshot_id],
                Tags=[
                    {'Key': 'Name', 'Value': f"Backup for instance {instance_id}"},
                    {'Key': 'Backup', 'Value': 'true'}
                ]
            )