Description: 

Security groups provide stateful filtering of ingress/egress network traffic to AWS resources. It is recommended that no security group allows unrestricted ingress access to Redis port 6379. If restricted ingress access to Redis port 6379 means we do not allow to access my Redis database.


Rationale: 

Removing unfettered connectivity to remote console services, such as SSH, reduces a server's exposure to risk. Ensure no security groups allow ingress from 0.0.0.0/0 or::/0 to Redis port 6379.


Impact:

In your security groups policy is allowing unrestricted inbound/ingress access on TCP port 6379(Redis) to your Amazon EC2 instances can increase opportunities for malicious activities such as cross-site scripting, remote code executions, brute-force, and crypto-jacking attack(e.g.RedisWannaMine) attacks. The associated security groups should be taken to ensure that administrators currently relying on an existing ingress from 0.0.0.0/0 have not to access Redis port 6379 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 note down 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.

  6. When you use Radis (port - 6379) and want to prevent the Radis server then you follow the below implementation steps.



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 6379 have the source set to 0.0.0.0/0 or::/0 (Anywhere), then the selected security group allows unrestricted data traffic on port 6379.


Using AWS CLI:

The following command describes a security group the command you can use for each security groups individual to check which IP or ports are inbound or outbound:

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 6379 port used only e.g. you can revoke any port   

aws ec2 revoke-security-group-ingress \
  --group-id <value> --protocol <protocol> --port 6379 --cidr 0.0.0.0/0


Backout 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 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: Open the security group by clicking on security group ID

Step 5: Click on Actions dropdown and select Delete Security groups

Using AWS CLI:

The following command is used to delete created security group id in the security_group_id enter the security group id which you show on your console.

aws ec2 delete-security-group --group-id <security_group_id>


Reference: