10 IoT Cyber Security
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10.6.2 Design the Cloud Service to be Resilient and Available
IoT services should be designed to operate in the face of adversity and to be
highly available. A robust cloud architecture will support these goals. For example,
implement load balancers in front of virtual servers to evenly distribute load across
applications and effectively handle peak traffic. You can also contract with Content
Delivery Networks (CDNs) to help improve the performance of your services. Make
use of CSP availability zones and regions and ensure that system infrastructure
spans multiple zones/regions. This will support disaster recovery. If a particular
availability zone or region goes dark, then failover will switch operations to the other
zones/regions. You can also implement rate-limiting on IoT APIs to defend against
malicious attacks coming from trusted devices that may have been compromised.
10.6.3 Securely Configure the Cloud Network
Each CSP offers the ability to configure firewall policies that restrict access from
external sources and from sources internal to the cloud. Make use of these policies
to restrict communications between subnets and nest sensitive resources such as
databases within subnets. For example, do not allow devices to interact directly
with cloud databases, instead require them to go through applications which are
then configured via policy as trusted by database subnets.
Additionally, ensure that all management access to servers in the cloud is secured.
This includes Secure Shell (SSH) access to manage virtual machines. Implement
strict policies and procedures for managing the SSK keys that allow access to each
VM. This includes restricting ownership and access to SSH keys within their VM
directories.
10.6.4 Apply Encryption to Cloud Communications
All cloud interfaces should be encrypted. Use Transport Layer Security (TLS)
whenever possible. When using User Datagram Protocol (UDP)-based protocols,
implement the Datagram TLS (DTLS) security system. Limit TLS cipher suites
used within your cloud configurations to those recommended in the latest version of
NIST SP 800-52. This will reduce the risk of a successful cipher suite downgrade
attack being run against your IoT systems.
505
10.6.2 Design the Cloud Service to be Resilient and Available
IoT services should be designed to operate in the face of adversity and to be
highly available. A robust cloud architecture will support these goals. For example,
implement load balancers in front of virtual servers to evenly distribute load across
applications and effectively handle peak traffic. You can also contract with Content
Delivery Networks (CDNs) to help improve the performance of your services. Make
use of CSP availability zones and regions and ensure that system infrastructure
spans multiple zones/regions. This will support disaster recovery. If a particular
availability zone or region goes dark, then failover will switch operations to the other
zones/regions. You can also implement rate-limiting on IoT APIs to defend against
malicious attacks coming from trusted devices that may have been compromised.
10.6.3 Securely Configure the Cloud Network
Each CSP offers the ability to configure firewall policies that restrict access from
external sources and from sources internal to the cloud. Make use of these policies
to restrict communications between subnets and nest sensitive resources such as
databases within subnets. For example, do not allow devices to interact directly
with cloud databases, instead require them to go through applications which are
then configured via policy as trusted by database subnets.
Additionally, ensure that all management access to servers in the cloud is secured.
This includes Secure Shell (SSH) access to manage virtual machines. Implement
strict policies and procedures for managing the SSK keys that allow access to each
VM. This includes restricting ownership and access to SSH keys within their VM
directories.
10.6.4 Apply Encryption to Cloud Communications
All cloud interfaces should be encrypted. Use Transport Layer Security (TLS)
whenever possible. When using User Datagram Protocol (UDP)-based protocols,
implement the Datagram TLS (DTLS) security system. Limit TLS cipher suites
used within your cloud configurations to those recommended in the latest version of
NIST SP 800-52. This will reduce the risk of a successful cipher suite downgrade
attack being run against your IoT systems.