Back to Control Explorer
SC.1.176
Content
Control Acronym
SC
Family
System And Communications Protection
CMMC Level
1
800-171 Control #
3.13.5
CMMC Description
Implement subnetworks for publicly accessible system components that are physically or logically separated from internal networks.
CMMC Clarification
Separate the publicly accessible systems from the internal systems that need to be protected. Do not place the internal systems on the same network as the publicly accessible systems. A network or part of a network that is separated (sometimes physically) from an internal network is called a demilitarized zone (DMZ). A DMZ is a host or part of a network put in a “neutral zone” between an organization’s internal network (the protected side) and a larger network, like the internet. To separate a subnetwork physically, your company may put in boundary control devices (i.e., routers, gateways, firewalls). This can also be done on a cloud network that can be separated from the rest of the network. A DMZ can add an extra layer of security to your company’s LAN, because an external network node can reach only what is permitted to be accessed in the DMZ. Physical separation might involve a separate network infrastructure, dedicated network equipment with separate LAN segments and a firewall between the internal network and the DMZ segment and a firewall between the DMZ segment and the internet. A logical separation might involve VLAN separation for the DMZ supporting a separate subnet with routing and access controls between subnets. Example The head of recruiting wants to launch a website to post job openings and allow the public to download an application form. After some discussion, your team realizes it needs to use a router and firewall to create a DMZ to do this. You host the server separately from the company’s internal network, and make sure the network has the correct security firewall rules. Your company gets a lot of great candidates for the open jobs, and the company’s internal network is protected.
800-171 Description
Implement subnetworks for publicly accessible system components that are physically or logically separated from internal networks.
800-171 Discussion
Subnetworks that are physically or logically separated from internal networks are referred to as demilitarized zones (DMZs). DMZs are typically implemented with boundary control devices and techniques that include routers, gateways, firewalls, virtualization, or cloud-based technologies. [SP 800-41] provides guidance on firewalls and firewall policy. [SP 800-125B] provides guidance on security for virtualization technologies.
Other Source Discussion
N/A
CIS Control References
CIS Controls v7.1 14.1
NIST 800-53 Control Ref.
NIST SP 800-53 Rev 4 SC-7
CMMC Derived
NIST CSF Control References
NIST 800-171 References
NIST SP 800-171 Rev 1 3.13.5
Applicable FAR Clause
FAR Clause 52.204-21 b.1.xi
NIST CSF Control Reference
CERT RMM Reference
Modification of NIST 800-171B Reference
NIST 800-171B Reference
UK NCSCCyber Reference
UK NCSC Cyber Essentials
AS ACSC Reference
Sub-Criterias
Assessment Sub-Criteria 1
SC.1.176.[a] publicly accessible system components are identified; and
Assessment Sub-Criteria 2
SC.1.176.[b] subnetworks for publicly accessible system components are physically or logically separated from internal networks.