Discovery can be configured to be on standard or basic mode. Use the standard option to actively find devices in your network, which will better guarantee the discovery of endpoints and provide richer device classification.
You can customize the list of devices that are used to perform standard discovery. You can either enable standard discovery on all the onboarded devices that also support this capability (currently – Windows 10 and Windows 2019 devices only) or select a subset or subsets of your devices by specifying their device tags.
Set up device discovery
To set up device discovery, take the following configuration steps in Microsoft 365 Defender portal:
Navigate to Settings > Device discovery
- If you want to configure Basic as the discovery mode to use on your onboarded devices, select Basic and then select Save
- If you’ve selected to use Standard discovery, select which devices to use for active probing: all devices or on a subset by specifying their device tags, and then select Save
Standard discovery uses various PowerShell scripts to actively probe devices in the network. Those PowerShell scripts are Microsoft signed and are executed from the following location:
C:\ProgramData\Microsoft\Windows Defender Advanced Threat Protection\Downloads\*.ps. For example,
C:\ProgramData\Microsoft\Windows Defender Advanced Threat Protection\Downloads\UnicastScannerV1.1.0.ps1.
Exclude devices from being actively probed in standard discovery
If there are devices on your network that shouldn’t be actively scanned (for example, devices used as honeypots for another security tool), you can also define a list of exclusions to prevent them from being scanned. Note that devices can still be discovered using Basic discovery mode and can also be discovered through multicast discovery attempts. Those devices will be passively discovered but won’t be actively probed.
You can configure the devices to exclude in the Exclusions page.
Select networks to monitor
Microsoft Defender for Endpoint analyzes a network and determines if it’s a corporate network that needs to be monitored or a non-corporate network that can be ignored. Corporate networks are typically chosen to be monitored. However, you can override this decision by choosing to monitor non-corporate networks where onboarded devices are found.
You can configure where device discovery can be performed by specifying which networks to monitor. When a network is monitored, device discovery can be performed on it.
A list of networks where device discovery can be performed is shown in the Monitored networks page.
The list shows networks that were identified as corporate networks. If less than 50 networks are identified as corporate networks, then list will show up to 50 networks with the most onboarded devices.
The list of monitored networks is sorted based upon the total number of devices seen on the network in the last 7 days.
You can apply a filter to view any of the following network discovery states:
- Monitored networks – Networks where device discovery is performed.
- Ignored networks – This network will be ignored and device discovery won’t be performed on it.
- All – Both monitored and ignored networks will be displayed.
Configure the network monitor state
You control where device discovery takes place. Monitored networks are where device discovery will be performed and are typically corporate networks. You can also choose to ignore networks or select the initial discovery classification after modifying a state.
Choosing the initial discovery classification means applying the default system-made network monitor state. Selecting the default system-made network monitor state means that networks that were identified to be corporate, will be monitored, and ones identified as non-corporate, will be ignored automatically.
- Select Settings > Device discovery.
- Select Monitored networks.
- View the list of networks.
- Select the three dots next to the network name.
- Choose whether you want to monitor, ignore, or use the initial discovery classification.
- Choosing to monitor a network that was not identified by Microsoft Defender for Endpoint as a corporate network can cause device discovery outside of your corporate network, and may therefore detect home or other non-corporate devices.
- Choosing to ignore a network will stop monitoring and discovering devices in that network. Devices that were already discovered won’t be removed from the inventory, but will no longer be updated, and details will be retained until the data retention period of the Defender for Endpoint expires.
- Before choosing to monitor non-corporate networks, you must ensure you have permission to do so.
- Confirm that you want to make the change.
Explore devices in the network
You can use the following advanced hunting query to get more context about each network name described in the networks list. The query lists all the onboarded devices that were connected to a certain network within the last 7 days.
DeviceNetworkInfo | where Timestamp > ago(7d) | where ConnectedNetworks != "" | extend ConnectedNetworksExp = parse_json(ConnectedNetworks) | mv-expand bagexpansion = array ConnectedNetworks=ConnectedNetworksExp | extend NetworkName = tostring(ConnectedNetworks ["Name"]), Description = tostring(ConnectedNetworks ["Description"]), NetworkCategory = tostring(ConnectedNetworks ["Category"]) | where NetworkName == "<your network name here>" | summarize arg_max(Timestamp, *) by DeviceId
Get information on device
You can use the following advanced hunting query to get the latest complete information on a specific device.
DeviceInfo | where DeviceName == "<device name here>" and isnotempty(OSPlatform) | summarize arg_max(Timestamp, *) by DeviceId