AU.L2-3.3.5  

Reference: CMMC 2.11

Family: AU

Level Introduced: 2

Title: Audit Correlation

Practice:
Correlate audit record review, analysis, and reporting processes for investigation and response to indications of unlawful, unauthorized, suspicious, or unusual activity.

CMMC Clarification:
Organizations must review, analyze, and report audit records to help detect and respond to security incidents in a timely manner for the purpose of investigation and corrective actions. Collection of audit logs into one or more central repositories (per AM.3.048) facilitates correlated review. Small organizations may be able to accomplish this manually. Larger organizations will use an automated system for analysis that does correlation of log information across the entire enterprise and supports the use of centralized intel feeds. By centralizing intel feeds, subscription costs should be reduced and the effectiveness of the analysis should be increased. Some organizations may want to orchestrate the entire analysis process which includes the use of APIs for collection, correlation, and the automation of responses based on programed rulesets.

Example 1
You are in charge of IT operations in your organization. You are responsible for assisting in the investigation of a possible incident. You review the event log for suspicious activity, e.g., a user logged on at an unusual time of day. In order to analyze the data, you use an automated tool to collect and analyze the audit log data, and perform queries to generate a detailed report. Once the connection is made between the individual and the incident, corrective actions are taken.

Example 2
You are a member of an adversary hunt team responsible for audit log analysis. You run an automated tool that analyzes all the audit logs across a LAN segment simultaneously looking for similar anomalies on separate systems at separate locations. After extracting anomalous information and performing a correlation analysis, you determine that four different systems have had their event log information cleared between 2:00 AM to 3:00 AM, although the associated dates are different. The hunt team monitors all systems on the same LAN segment between 2:00 AM to 3:00 AM for the next 30 days.

Source: CMMC v2.0