Check ID:
Provider: Azure
Service:
Severity: HIGH
Categories:
Resource type:
network_flow_log_captured_sentProvider: Azure
Service:
networkSeverity: HIGH
Categories:
logging, forensics-readyResource type:
microsoft.network/networkwatchersWhat this check verifies
Azure Network Watcher has NSG flow logs enabled and configured to forward traffic records to a centralized Log Analytics workspaceRisk
Missing or disabled flow logging blinds visibility into network behavior, hindering detection of:- Lateral movement and internal scanning
- C2 beacons and exfiltration patterns This degrades incident response and correlation, impacting confidentiality and integrity.
Recommendation
Enable and centrally aggregate NSG flow logs to a Log Analytics workspace.- Enforce least privilege on log data
- Define retention and secure storage
- Use layered monitoring (e.g., Traffic Analytics)
- Ensure coverage across regions/subscriptions and critical NSGs
Remediation
- CLI
- Terraform
- Native IaC
- Dashboard steps
az network watcher flow-log create —location <REGION> —name <FLOW_LOG_NAME> —resource-group <RESOURCE_GROUP> —nsg <NSG_NAME> —storage-account <STORAGE_ACCOUNT_NAME> —enabled true —workspace <LOG_ANALYTICS_WORKSPACE_ID>
References
- https://learn.microsoft.com/en-us/azure/network-watcher/vnet-flow-logs-tutorial
- https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-logging-threat-detection#lt-4-enable-network-logging-for-security-investigation
Where this check fires
This check runs on every scheduled scan against your Azure account. Findings appear at Cloud Security → Findings filterable byCheck ID = network_flow_log_captured_sent. To re-evaluate after a fix, hit Run now on the account’s schedule under Cloud Security → Schedules — the next scan re-checks this control and marks the finding fixed or keeps it persistent.
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