13.6
IG2 IG3

Collect Network Traffic Flow Logs

Asset Type: Network
Security Function: Detect

Description

Collect network traffic flow logs and/or network traffic to review and alert upon from network devices.

Implementation Checklist

1
Deploy detection tools or enable detection capabilities
2
Configure alerting thresholds and notification channels
3
Establish monitoring schedule and review process
4
Test detection capabilities with simulated events
5
Document detection procedures and escalation paths
6
Enable logging on all in-scope systems
7
Configure log forwarding to centralized SIEM
8
Define log retention periods per policy
9
Establish log review schedule and procedures

Threats & Vulnerabilities (CIS RAM)

Threat Scenarios

Covert Data Exfiltration via Unusual Traffic Patterns

Confidentiality

An attacker slowly exfiltrates sensitive data using low-and-slow techniques over legitimate ports, and the abnormal traffic volume goes unnoticed because network flow logs are not collected or analyzed.

Undetected Reconnaissance Scanning of Internal Network

Confidentiality

An attacker conducts port scans and service enumeration across the internal network after initial compromise, and the scanning activity is invisible because no network traffic flow logging is in place.

Unauthorized Communication to Known Malicious Infrastructure

Integrity

A compromised system communicates with known threat actor infrastructure, but the outbound connections are never flagged because network flow data is not captured for threat intelligence correlation.

Vulnerabilities (When Safeguard Absent)

No Network Flow Visibility

Without collecting NetFlow or equivalent traffic flow logs, security teams cannot identify abnormal communication patterns, traffic volumes, or unauthorized connections between internal and external systems.

Inability to Perform Retrospective Network Analysis

Absence of historical network traffic flow data prevents forensic investigation of when compromise began, what systems communicated with attacker infrastructure, and what data may have been exfiltrated.

Evidence Requirements

Type Evidence Item Collection Frequency
Technical Detection tool deployment evidence (dashboard screenshots, agent status) Captured monthly
Technical Sample alert/detection output demonstrating capability Captured quarterly
Technical SIEM dashboard showing log sources and collection status Captured monthly
Record Log review records and findings Per review cycle
Document Governing policy document (current, approved, communicated) Reviewed annually