Description: 

Security groups provide state full filtering of ingress/egress network traffic to AWS resources. It is recommended that no security group allows unrestricted ingress access to MySQL ports 3306. If restricted ingress access to MySQL ports means we do not allow to access my database.


Rationale: 

Removing unfettered connectivity to remote console services, and nobody will access my internal database server or Oracle, reduces a database server’s exposure to risk. 


Impact:

If we do not allow unrestricted ingress/inbound access to MySQL port 3306 It can have minimized the opportunities for malicious activity such as hacking, data loss, and all multiple types of attacks( brute-force attacks, Denial of Service (DoS) attacks, etc).

For updating an existing environment, care should be taken to ensure that administrators currently relying on an existing ingress from 0.0.0.0/0 have access to MySQL port 3306 through another security group. 


Default Value:

VPC automatically comes with a default security group. If you don't specify a different security group when you launch the instance, the default security group will be associated with the instance. By default, the security group allows all inbound connections.  


Pre-Requisite:

  1. Before starting, the below implementation steps write all configurations which IP and which port in the inbound.

  2. Avoid the login through the Root user.

  3. Only authorized persons (i.e, admins) can access the Security Groups.

  4. You cannot delete the default security groups but you can edit and modify them here so you can create security groups and create your own rules in them.

  5. Do not attach the default security group to any EC2 instance if you do not modify any default rules in inbound or outbound.

  6. When you will use the services MySQL Port 3306 as a database server.


Remediation:

Test Plan:

  1. Sign in to the AWS Management Console.

  2. Navigate to the EC2 dashboard at https://console.aws.amazon.com/ec2/.

  3. Click on Security Groups, under the NETWORK & SECURITY section, in the left navigation pane

  4. Verify the value in the Source column for any inbound rules with the Port Range set to 3306 have the source set to 0.0.0.0/0 or::/0 (Anywhere), then the selected security group allows unrestricted data traffic on port 3306.



Using AWS CLI:

The following command describes a security group 

aws ec2 describe-security-groups --group-ids <secuiryt_group_id>


Implementation Steps:

Step 1: Sign in to the AWS Management Console.

Step 2: Go to the EC2 dashboard at https://console.aws.amazon.com/ec2/.

Step 3: Click on Security Groups, under the NETWORK & SECURITY section, in the left navigation pane

Step 4: Select the appropriate security group (see Audit section to identify the right one(s)).

Step 5: Select the Inbound tab and click the Edit inbound rules button.

Step 6: In the Edit inbound rules dialog box, go-to source column and perform one of the following actions to restrict the inbound traffic: Click on the source dropdown

  1. Select My IP to allow inbound traffic only from your machine (i.e, from your IP address only).

  2. Select Custom and enter IP addresses or name or ID of another security group based on your access requirements


Step 7: Click Save to apply the changes.


Using AWS CLI

List all security groups with an ingress rule of 0.0.0.0/0 

aws ec2 describe-security-groups --filters Name=ip-permission.cidr,Values='0.0.0.0/0' \
    --query "SecurityGroups[*].{Name:GroupName,ID:GroupId}"

Remove the rule 3306 port used only e.g. you can revoke any port  

aws ec2 revoke-security-group-ingress \
  --group-id <value> --protocol <protocol> --port 3306 --cidr 0.0.0.0/0


Back out Plan:

If you want to proceed with previous settings go through the Implementation steps section and set all previous policies that you have written somewhere. Or else you can delete the security group you created

Step 1:Sign into the AWS Management Console.

Step 2:Go to EC2 dashboard at https://console.aws.amazon.com/ec2/.

Step 3: Click on Security Groups, under the NETWORK & SECURITY section, in the left navigation pane

Step 4: Open the security group by clicking on the security group ID

Step 5: Click on Actions dropdown and select Edit inbound rules 

Step 6: Click on Edit inbound rules button and select Type “All traffic”  Protocol “All “ and port range “All” and save it. 


Using AWS CLI:

aws ec2 authorize-security-group-ingress 
 --group-id <value>
  --protocol all
 --port all

Reference:

  1. https://docs.aws.amazon.com/cli/latest/reference/ec2/revoke-security-group-ingress.html

  2. https://docs.aws.amazon.com/cli/latest/reference/lightsail/get-instance-port-states.html

  3. https://docs.aws.amazon.com/cli/latest/reference/ec2/describe-security-groups.html

  4. https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-security-group-ingress.html