ELB with service 'NetBios Session Service' (UDP:139) is exposed to a wide network scope

Risk Level: Medium
Cloud Entity: Elastic Load Balancing (ELB)
CloudGuard Rule ID: D9.AWS.NET.AG2.6.ELB.139.UDP
Covered by Spectral: No
Category: Networking & Content Delivery

GSL LOGIC

ELB where inboundRules contain [port <= 139 and portTo >= 139 and protocol in ('UDP','ALL')] should not have inboundRules contain [port <= 139 and portTo >= 139 and protocol in ('UDP','ALL') and scope numberOfHosts() > 256]

REMEDIATION

Limit the access scope for ELB with service 'NetBios Session Service to only allow access in internal networks and limited scope.

If public interface exists, remove it and limit the access scope within the VPC only to applications or instances that requires access.

Amazon Reference: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/authorizing-access-to-an-instance.html

As a further protection step, Use CloudGuard 'Tamper Protection' (Full Protection mode) and region lock to prevent unauthorized changes to network access settings, refer to https://sc1.checkpoint.com/documents/CloudGuard_Dome9/Documentation/Network-Security/FullProtectionMode.html?Highlight=full%20protection for more details.

Elastic Load Balancing (ELB)

Elastic Load Balancing automatically distributes incoming application traffic across multiple targets, such as Amazon EC2 instances, containers, and IP addresses. It can handle the varying load of your application traffic in a single Availability Zone or across multiple Availability Zones. Elastic Load Balancing offers three types of load balancers that all feature the high availability, automatic scaling, and robust security necessary to make your applications fault tolerant.

Compliance Frameworks

• BP-0318
• LGPD
• NETWSEC-V2