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Security group does not allow ingress from 0.0.0.0/0 or ::/0 to TCP port 9092 (Kafka)

ec2_securitygroup_allow_ingress_from_internet_to_tcp_port_kafka_9092
Service: ec2Severity: high
OfficialBuilt-inVerified
Categories:internet-exposed
Resource Type:AwsEc2SecurityGroup

EC2 security groups are evaluated for ingress rules that expose Kafka on TCP 9092 to the Internet via 0.0.0.0/0 or ::/0

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Risk

Public Kafka 9092 access allows arbitrary clients to connect, enabling topic enumeration, data exfiltration, and producer/consumer impersonation (C/I). Brokers can be flooded or exploited, disrupting clusters (A). Exposure gives attackers a foothold for lateral movement inside the VPC.

Run this check with Prowler

Run in Prowler Cloud
Run
prowler aws --checks ec2_securitygroup_allow_ingress_from_internet_to_tcp_port_kafka_9092

Recommendation

Apply least privilege: restrict 9092 to required subnets or IPs; avoid 0.0.0.0/0 and ::/0. Place brokers on private networks and use peering or VPN for access. Enforce mutual TLS/SASL and topic ACLs, and add defense in depth with segmentation and NACLs.

Remediation

CLI

aws ec2 revoke-security-group-ingress --group-id <SECURITY_GROUP_ID> --ip-permissions '[{"IpProtocol":"tcp","FromPort":9092,"ToPort":9092,"IpRanges":[{"CidrIp":"0.0.0.0/0"}],"Ipv6Ranges":[{"CidrIpv6":"::/0"}]}]'

Terraform

# Restrict Kafka (9092) from Internet
resource "aws_security_group" "<example_resource_name>" {
  name   = "<example_resource_name>"
  vpc_id = "<example_resource_id>"

  ingress {
    from_port   = 9092
    to_port     = 9092
    protocol    = "tcp"
    cidr_blocks = ["10.0.0.0/8"] # Critical: not 0.0.0.0/0; restricts access to avoid Internet exposure
  }
}

NativeIaC

# CloudFormation: restrict Kafka (9092) from Internet
Resources:
  <example_resource_name>:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: Restrict Kafka 9092
      VpcId: <example_resource_id>
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 9092
          ToPort: 9092
          CidrIp: 10.0.0.0/8  # Critical: not 0.0.0.0/0; restricts access to private range to avoid Internet exposure

Other

1In AWS Console, go to EC2 > Security Groups
2Select the group attached to the resource
3Inbound rules > Edit inbound rules
4Find any rule for TCP port 9092 with Source 0.0.0.0/0 or ::/0
5Delete the rule or change Source to a specific trusted CIDR or security group
6Save rules

Check Code

from prowler.lib.check.models import Check, Check_Report_AWS
from prowler.providers.aws.services.ec2.ec2_client import ec2_client
from prowler.providers.aws.services.ec2.ec2_securitygroup_allow_ingress_from_internet_to_all_ports import (
    ec2_securitygroup_allow_ingress_from_internet_to_all_ports,
)
from prowler.providers.aws.services.ec2.lib.security_groups import check_security_group
from prowler.providers.aws.services.vpc.vpc_client import vpc_client


class ec2_securitygroup_allow_ingress_from_internet_to_tcp_port_kafka_9092(Check):
    def execute(self):
        findings = []
        check_ports = [9092]
        for security_group_arn, security_group in ec2_client.security_groups.items():
            # Check if ignoring flag is set and if the VPC and the SG is in use
            if ec2_client.provider.scan_unused_services or (
                security_group.vpc_id in vpc_client.vpcs
                and vpc_client.vpcs[security_group.vpc_id].in_use
                and len(security_group.network_interfaces) > 0
            ):
                report = Check_Report_AWS(
                    metadata=self.metadata(), resource=security_group
                )
                report.resource_details = security_group.name
                report.status = "PASS"
                report.status_extended = f"Security group {security_group.name} ({security_group.id}) does not have Kafka port 9092 open to the Internet."
                # only proceed if check "..._to_all_ports" did not run or did not FAIL to avoid to report open ports twice
                if not ec2_client.is_failed_check(
                    ec2_securitygroup_allow_ingress_from_internet_to_all_ports.__name__,
                    security_group_arn,
                ):
                    # Loop through every security group's ingress rule and check it
                    for ingress_rule in security_group.ingress_rules:
                        if check_security_group(
                            ingress_rule, "tcp", check_ports, any_address=True
                        ):
                            report.status = "FAIL"
                            report.status_extended = f"Security group {security_group.name} ({security_group.id}) has Kafka port 9092 open to the Internet."
                            break
                else:
                    report.status_extended = f"Security group {security_group.name} ({security_group.id}) has all ports open to the Internet and therefore was not checked against the specific Kafka port 9092."

                findings.append(report)

        return findings

References