VPC security group rules should not permit ingress from ‘0.0.0.0/0’ to TCP port 9200 (Elasticsearch)

Description

VPC security groups should not permit unrestricted access from the internet to port 9200 (Elasticsearch). Removing unfettered connectivity to an Elasticsearch server reduces the chance of exposing critical data.

Remediation Steps

AWS Console

  • Navigate to VPC.

  • In the left navigation pane, click Security Groups.

    • Remove any rules that include port 9200 and have a source of 0.0.0.0/0.

    • Click Save.

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 inbound rule(s) that permits unrestricted ingress to port 9200:

    • aws ec2 revoke-security-group-ingress --region <region> --group-name <group_name> --protocol <protocol> --port 9200 --cidr 0.0.0.0/0

  • Optionally add a more restrictive ingress rule to the selected Security Group:

    • aws ec2 authorize-security-group-ingress --region <region> --group-name <group_name> --protocol <protocol> --port 9200 --cidr <cidr_block>

Terraform

  • Ensure that an aws_security_group ingress block does NOT contain both of the following:

    • A 0.0.0.0/0 in the cidr_blocks field

    • 9200 is within the port range defined from from_port to to_port, OR from_port and to_port are both set to 0

Example Configuration

resource "aws_security_group" "example" {
  ingress {
    cidr_blocks = [10.0.0.0/16]
    from_port   = 9200
    to_port     = 9200
    # other required fields here
  }
}