Level 5 CMMC - CMMC Practices

SI.5.223  

Reference: CMMC 1.02

Family: SI

Level Introduced: 5

Practice:
Monitor individuals and system components on an ongoing basis for anomalous or suspicious behavior.

CMMC Clarification:
Monitoring for anomalous or suspicious behavior can be done with signatures, statistical analysis, analytics or machine learning on user activity events. The analysis seeks to find patterns amongst data generated by user activity. This is different than traditional security applications that analyze events. This class of analysis is typically called User and Entity Behavior Analytics (UEBA).

Example
You are working the night shift in the Security Operations Center (SOC). You notice alerts related to someone from accounting. That person doesn’t use their computer at this time of night so the monitoring system has identified anomalous activity. The algorithms identify activity outside business hours and an excessive data upload from a key server on the network using that account. You initiate an investigation to determine the source and risk from the data exfiltration.

Additional Reading
Ten Strategies of a World-class Cybersecurity Operations Center: https://www.mitre.org/sites/default/files/publications/pr-13-1028-mitre-10-strategies- cyber-ops-center.pdf
SANS Common and Best Practices for Security Operations Centers: Results of the 2019 SOC Survey: https://www.sans.org/media/analyst-program/common-practices-security- operations-centers-results-2019-soc-survey-39060.pdf

3.14.2e

Monitor organizational systems and system components on an ongoing basis for anomalous or suspicious behavior.

Discussion:
Monitoring is used to identify unusual, suspicious, or unauthorized activities or conditions related to organizational systems and system components. Such activities or conditions can include unusual internal systems communications traffic, unauthorized exporting of information,signaling to external systems, large file transfers, long-time persistent connections, attempts to access information from unexpected locations, unusual protocols and ports in use, and attempted communications with suspected malicious external addresses.

The correlation of physical audit record information to the audit records from systems may assist organizations in identifying examples of anomalous behavior. For example, the correlation of an individual’s identity for logical access to certain systems with the additional information that the individual was not present at the facility when the logical access occurred is indicative of anomalous behavior.

[SP 800-61] provides guidance on incident handling. [SP 800-83] provides guidance for malicious code incident prevention and handling. [SP 800-92] provides guidance on computer security log management. [SP 800-94] provides guidance on intrusion detection and prevention. [SP 800-137] provides guidance on continuous monitoring of systems.

Source: NIST Special Publication 800-172 (Draft)

SI-4

INFORMATION SYSTEM MONITORING

Description:
The organization:
    a. Monitors the information system to detect:
        1. Attacks and indicators of potential attacks in accordance with [Assignment: organization-defined monitoring objectives]; and
        2. Unauthorized local, network, and remote connections;
    b. Identifies unauthorized use of the information system through [Assignment: organization-defined techniques and methods];
    c. Deploys monitoring devices:
        1. Strategically within the information system to collect organization-determined essential information; and
        2. At ad hoc locations within the system to track specific types of transactions of interest to the organization;
    d. Protects information obtained from intrusion-monitoring tools from unauthorized access, modification, and deletion;
    e. Heightens the level of information system monitoring activity whenever there is an indication of increased risk to organizational operations and assets, individuals, other organizations, or the Nation based on law enforcement information, intelligence information, or other credible sources of information;
    f. Obtains legal opinion with regard to information system monitoring activities in accordance with applicable federal laws, Executive Orders, directives, policies, or regulations; and
    g. Provides [Assignment: organization-defined information system monitoring information] to [Assignment: organization-defined personnel or roles] [Selection (one or more): as needed; [Assignment: organization-defined frequency]].

Supplemental Guidance:
Information system monitoring includes external and internal monitoring. External monitoring includes the observation of events occurring at the information system boundary (i.e., part of perimeter defense and boundary protection). Internal monitoring includes the observation of events occurring within the information system. Organizations can monitor information systems, for example, by observing audit activities in real time or by observing other system aspects such as access patterns, characteristics of access, and other actions. The monitoring objectives may guide determination of the events. Information system monitoring capability 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). Strategic locations for monitoring devices include, for example, selected perimeter locations and near server farms supporting critical applications, with such devices typically being employed at the managed interfaces associated with controls SC-7 and AC-17. Einstein network monitoring devices from the Department of Homeland Security can also be included as monitoring devices. The granularity of monitoring information collected is based on organizational monitoring objectives and the capability of information systems to support such objectives. Specific types of transactions of interest include, for example, Hyper Text Transfer Protocol (HTTP) traffic that bypasses HTTP proxies. Information system monitoring is an integral part of organizational continuous monitoring and incident response programs. Output from system monitoring serves as input to continuous monitoring and incident response programs. A network connection is any connection with a device that communicates through a network (e.g., local area network, Internet). A remote connection is any connection with a device communicating through an external network (e.g., the Internet). Local, network, and remote connections can be either wired or wireless. Related controls: AC-3, AC-4, AC-8, AC-17, AU-2, AU-6, AU-7, AU-9, AU-12, CA-7, IR-4, PE-3, RA-5, SC-7, SC-26, SC-35, SI-3, SI-7.

Source: NIST Special Publication 800-53 Rev. 4

Source: CMMC v1.02