Information
Ensure that network flow logs are captured and fed into a central log analytics workspace.
Retirement Notice
On September 30, 2027, network security group (NSG) flow logs will be retired. As of June 30, 2025, creating new NSG flow logs is no longer possible. Azure recommends migrating to virtual network flow logs. Review https://azure.microsoft.com/en-us/updates?id=Azure-NSG-flow-logs-Retirement for more information.
For virtual network flow logs, consider applying the recommendation, Ensure that virtual network flow logs are captured and sent to Log Analytics, from this section.
Network Flow Logs provide valuable insight into the flow of traffic around your network and feed into both Azure Monitor and Azure Sentinel (if in use), permitting the generation of visual flow diagrams to aid with analyzing for lateral movement, etc.
NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.
Solution
As of June 30, 2025, creating new NSG flow logs is no longer possible. Azure recommends migrating to virtual network flow logs. Consider applying the recommendation, Ensure that virtual network flow logs are captured and sent to Log Analytics, from this section.
Impact:
The impact of configuring NSG Flow logs is primarily one of cost and configuration. If deployed, it will create storage accounts that hold minimal amounts of data on a 5-day lifecycle before feeding to Log Analytics Workspace.This will increase the amount of data stored and used by Azure Monitor.