Requirement text: SI.2.217: Identify unauthorized use of organizational systems.
DISCUSSION FROM SOURCE: DRAFT NIST SP 800-171 R2
System monitoring includes external and internal monitoring. System monitoring can detect
unauthorized use of organizational systems. System monitoring is an integral part of
continuous monitoring and incident response programs. Monitoring is achieved through a
variety of tools and techniques (e.g., intrusion detection systems, intrusion prevention
systems, malicious code protection software, scanning tools, audit record monitoring
software, network monitoring software). Output from system monitoring serves as input to
continuous monitoring and incident response programs.
Unusual/unauthorized activities or conditions related to inbound and outbound
communications traffic include internal traffic that indicates the presence of malicious code
in systems or propagating among system components, the unauthorized exporting of
information, or signaling to external systems. Evidence of malicious code is used to identify
potentially compromised systems or system components. System monitoring requirements,
including the need for specific types of system monitoring, may be referenced in other
requirements.
NIST SP 800-94 provides guidance on intrusion detection and prevention systems.
CMMC CLARIFICATION
Organizations should define authorized use of their systems. First, have an acceptable-use
policy for your system. This policy establishes the baseline for how users access devices and
the internet. You define authorized use by specific roles within the organization. Examples
of these roles include user, administrator, and technician. After you define authorized use,
identify unauthorized use of systems.
Organizations can monitor systems by observing audit activities. You can do this in real time
or by other manual means, such as access patterns. To identify unauthorized use, leverage
existing tools and techniques, such as:
• intrusion detection systems;
• intrusion prevention systems;
• malicious code protection software;
• scanning tools;
• audit record monitoring software; and
• network monitoring software.
Example
You are in charge of IT operations at your organization. You want to make sure everyone
using an organizational system is authorized to do so. You accomplish this as part of your
monitoring activities. These activities ensure that all users meet the defined authorize-use
policy. To do this, you put in place a user activity monitoring application. This app monitors
all the users and their connections to your network. It records information about every
connection on your network. You use the outputs of this application to confirm that you are
meeting the authorization policy.
References
• NIST SP 800-171 Rev 1 3.14.7
• NIST CSF v1.1 DE.CM-1, DE.CM-7
• CERT RMM v1.2 MON:SG1.SP3
• NIST SP 800-53 Rev 4 SI-4