Hunt for devices organized by subnet

Group by: NetworkAddress
Author: Robbe Van den Daele
Source: github.com/HybridBrothers/Hunting-Queries-Detection-Rules

This rule helps you organize devices by subnet in your networks. By doing this, you can identify how many not-onboarded devices, devices not supporting MDE containment, and types of devices live in your subnet ranges.

References

https://hybridbrothers.com/device-isolation-and-containment-strategies/

Rule body yaml

let isolationSupportedOS = dynamic(["Windows11", "Windows10", "WindowsServer2025", "WindowsServer2022", "WindowsServer2019", "WindowsServer2016", "WindowsServer2012R2", "Linux", "macOS"]);
let containmentSupportedOS = dynamic(["Windows11", "Windows10", "WindowsServer2025", "WindowsServer2022", "WindowsServer2019", "WindowsServer2016", "WindowsServer2012R2"]);
let base = DeviceNetworkInfo
    // Expand all IPs
    | mv-expand todynamic(IPAddresses)
    // Ignore IPv6 addresses
    | where tostring(IPAddresses.IPAddress) !contains ":"
    // Save the Prefix as an extra property and set it to /32 when empty
    | extend Prefix = iff(isnotempty(tostring(IPAddresses.SubnetPrefix)), tostring(IPAddresses.SubnetPrefix), "32");
let networks = base
    // Get network addresses with a non /32 prefix
    | where Prefix != "32"
    // Get the network address related to the IP
    | extend NetworkAddress = format_ipv4(tostring(IPAddresses.IPAddress), tolong(Prefix))
    // Build the IP and Network Address with the CIDR notation
    | extend IPAddress = strcat(tostring(IPAddresses.IPAddress), "/", Prefix)
    | extend NetworkAddress = strcat(NetworkAddress, "/", Prefix)
    // Join the Device Info information
    | join kind=inner DeviceInfo on DeviceId, ReportId
    // Ignore APIPA addresses
    | where NetworkAddress != "169.254.0.0/16"
    // Ignore merged device IDs
    | where MergedToDeviceId == ""
    // Make a set of all the Device Objects belonging to the same subnet
    | extend DeviceObj = pack(
        "DeviceName", DeviceName,
        "IPAddress", IPAddress,
        "DeviceType", DeviceType,
        "DeviceCategory", DeviceCategory,
        "IsInternetFacing", IsInternetFacing,
        "OnboardingStatus", OnboardingStatus,
        "OSDistribution", OSDistribution,
        "OSPlatform", OSPlatform
    )
    // Make a list of the objects in the same subnet
    | summarize make_set(DeviceObj) by NetworkAddress;
let device_with_host_prefix = base
    // Get network addresses with /32 Prefix to try and match other networks
    | where Prefix == "32"
    // Build the IP Address with the CIDR notation
    | extend IPAddress = strcat(tostring(IPAddresses.IPAddress), "/", Prefix)
    // Join the Device Info information
    | join kind=inner DeviceInfo on DeviceId, ReportId
    // Ignore merged device IDs
    | where MergedToDeviceId == ""
    // Make a set of all the Device Objects
    | extend DeviceObj = pack(
        "DeviceName", DeviceName,
        "IPAddress", IPAddress,
        "DeviceType", DeviceType,
        "DeviceCategory", DeviceCategory,
        "IsInternetFacing", IsInternetFacing,
        "OnboardingStatus", OnboardingStatus,
        "OSDistribution", OSDistribution,
        "OSPlatform", OSPlatform
    )
    | extend Joiner = 1;
let network_addresses = base
    // Get network addresses with a non /32 prefix
    | where Prefix != "32"
    // Get the network address related to the IP
    | extend NetworkAddress = format_ipv4(tostring(IPAddresses.IPAddress), tolong(Prefix))
    | extend NetworkAddress = strcat(NetworkAddress, "/", Prefix)
    // Create joiner to find host addresses related to certain networks
    | distinct NetworkAddress
    | extend Joiner = 1;
let networks2 = device_with_host_prefix
    // Try to join /32 IPs
    | join kind=inner network_addresses on Joiner
    // Check if IP is in the network range, and only return those IPs
    | extend InRange = ipv4_is_in_range(IPAddress, NetworkAddress)
    | where InRange == 1
    // Make a list of the objects in the same subnet
    | summarize make_set(DeviceObj) by NetworkAddress;
union networks, networks2
    // Expand the Device Objects
    | mv-expand set_DeviceObj
    // Save the DeviceType, DeviceCategory, and Onboarding Status
    | extend DeviceType = set_DeviceObj.DeviceType
    | extend DeviceCategory = set_DeviceObj.DeviceCategory
    | extend OnboardingStatus = set_DeviceObj.OnboardingStatus
    // Count how many servers, workstations, network devices, iot devices, and ot devices exists in a subnet, the onboarding estate, and OS Distribution
    | summarize Servers = countif(set_DeviceObj.DeviceType=="Server"),
        Workstations = countif(set_DeviceObj.DeviceType=="Workstation"),
        NetworkDevices = countif(set_DeviceObj.DeviceCategory=="NetworkDevice"),
        IoTDevices = countif(set_DeviceObj.DeviceCategory=="IoT"),
        OTDevices = countif(set_DeviceObj.DeviceCategory=="OT"),
        Onboarded = countif(set_DeviceObj.OnboardingStatus=="Onboarded"),
        NotOnboarded = countif(set_DeviceObj.OnboardingStatus!="Onboarded"),
        IsolateSupportedOS = countif((set_DeviceObj.OSDistribution has_any (isolationSupportedOS) or set_DeviceObj.OSPlatform == "Linux") and set_DeviceObj.OnboardingStatus == "Onboarded"),
        ContainSupportedOS = countif(set_DeviceObj.OSDistribution has_any (containmentSupportedOS) and set_DeviceObj.OnboardingStatus == "Onboarded") by NetworkAddress
    // Join the network subnets so we have the device objects again
    | join kind=leftouter networks on NetworkAddress
    | join kind=leftouter networks2 on NetworkAddress
    // Extend Array Concat
    | extend set_DeviceObj = array_concat(set_DeviceObj, set_DeviceObj1)
    // Remove duplicate columns
    | project-away NetworkAddress1, NetworkAddress2, set_DeviceObj1
    // Count how many IPs there are in one subnet
    | extend CountIPs = array_length(set_DeviceObj)
    | sort by CountIPs desc

Stages and Predicates

Parameters

let containmentSupportedOS = dynamic(["Windows11", "Windows10", "WindowsServer2025", "WindowsServer2022", "WindowsServer2019", "WindowsServer2016", "WindowsServer2012R2"]);

Let binding: `isolationSupportedOS`

let isolationSupportedOS = dynamic(["Windows11", "Windows10", "WindowsServer2025", "WindowsServer2022", "WindowsServer2019", "WindowsServer2016", "WindowsServer2012R2", "Linux", "macOS"]);

Let binding: `base`

let base = DeviceNetworkInfo
    | mv-expand todynamic(IPAddresses)
    | where tostring(IPAddresses.IPAddress) !contains ":"
    | extend Prefix = iff(isnotempty(tostring(IPAddresses.SubnetPrefix)), tostring(IPAddresses.SubnetPrefix), "32");

Let binding: `networks`

let networks = base
    | where Prefix != "32"
    | extend NetworkAddress = format_ipv4(tostring(IPAddresses.IPAddress), tolong(Prefix))
    | extend IPAddress = strcat(tostring(IPAddresses.IPAddress), "/", Prefix)
    | extend NetworkAddress = strcat(NetworkAddress, "/", Prefix)
    | join kind=inner DeviceInfo on DeviceId, ReportId
    | where NetworkAddress != "169.254.0.0/16"
    | where MergedToDeviceId == ""
    | extend DeviceObj = pack(
        "DeviceName", DeviceName,
        "IPAddress", IPAddress,
        "DeviceType", DeviceType,
        "DeviceCategory", DeviceCategory,
        "IsInternetFacing", IsInternetFacing,
        "OnboardingStatus", OnboardingStatus,
        "OSDistribution", OSDistribution,
        "OSPlatform", OSPlatform
    )
    | summarize make_set(DeviceObj) by NetworkAddress;

Derived from base.

Let binding: `device_with_host_prefix`

let device_with_host_prefix = base
    | where Prefix == "32"
    | extend IPAddress = strcat(tostring(IPAddresses.IPAddress), "/", Prefix)
    | join kind=inner DeviceInfo on DeviceId, ReportId
    | where MergedToDeviceId == ""
    | extend DeviceObj = pack(
        "DeviceName", DeviceName,
        "IPAddress", IPAddress,
        "DeviceType", DeviceType,
        "DeviceCategory", DeviceCategory,
        "IsInternetFacing", IsInternetFacing,
        "OnboardingStatus", OnboardingStatus,
        "OSDistribution", OSDistribution,
        "OSPlatform", OSPlatform
    )
    | extend Joiner = 1;

Derived from base.

Let binding: `network_addresses`

let network_addresses = base
    | where Prefix != "32"
    | extend NetworkAddress = format_ipv4(tostring(IPAddresses.IPAddress), tolong(Prefix))
    | extend NetworkAddress = strcat(NetworkAddress, "/", Prefix)
    | distinct NetworkAddress
    | extend Joiner = 1;

Derived from base.

Let binding: `networks2`

let networks2 = device_with_host_prefix
    | join kind=inner network_addresses on Joiner
    | extend InRange = ipv4_is_in_range(IPAddress, NetworkAddress)
    | where InRange == 1
    | summarize make_set(DeviceObj) by NetworkAddress;

Derived from device_with_host_prefix, network_addresses.

union (2 sources)

Each leg below queries one source; the rule matches if any leg does. Sources: networks, networks2

Leg 1: `networks`

Leg 2: `networks2`

Applied to the combined result

| mv-expand set_DeviceObj | extend DeviceType = set_DeviceObj.DeviceType | extend DeviceCategory = set_DeviceObj.DeviceCategory | extend OnboardingStatus = set_DeviceObj.OnboardingStatus | summarize Servers = countif(set_DeviceObj.DeviceType=="Server"),
        Workstations = countif(set_DeviceObj.DeviceType=="Workstation"),
        NetworkDevices = countif(set_DeviceObj.DeviceCategory=="NetworkDevice"),
        IoTDevices = countif(set_DeviceObj.DeviceCategory=="IoT"),
        OTDevices = countif(set_DeviceObj.DeviceCategory=="OT"),
        Onboarded = countif(set_DeviceObj.OnboardingStatus=="Onboarded"),
        NotOnboarded = countif(set_DeviceObj.OnboardingStatus!="Onboarded"),
        IsolateSupportedOS = countif((set_DeviceObj.OSDistribution has_any (isolationSupportedOS) or set_DeviceObj.OSPlatform == "Linux") and set_DeviceObj.OnboardingStatus == "Onboarded"),
        ContainSupportedOS = countif(set_DeviceObj.OSDistribution has_any (containmentSupportedOS) and set_DeviceObj.OnboardingStatus == "Onboarded") by NetworkAddress | join kind=leftouter networks on NetworkAddress | join kind=leftouter networks2 on NetworkAddress | extend set_DeviceObj = array_concat(set_DeviceObj, set_DeviceObj1) | project-away NetworkAddress1, NetworkAddress2, set_DeviceObj1 | extend CountIPs = array_length(set_DeviceObj) | sort by CountIPs desc

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`IPAddress`	contains	`:`
`IPAddress`	contains	`:`
`IPAddress`	contains	`:`
`IPAddress`	contains	`:`
`IPAddress`	contains	`:`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`InRange`	eq	`1` transforms: `cased`
`NetworkAddress`	ne	`169.254.0.0/16` transforms: `cased`
`Prefix`	eq	`32` transforms: `cased`
`Prefix`	ne	`32` transforms: `cased`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field	Source
`ContainSupportedOS`	`summarize`
`IoTDevices`	`summarize`
`IsolateSupportedOS`	`summarize`
`NetworkAddress`	`summarize`
`NetworkDevices`	`summarize`
`NotOnboarded`	`summarize`
`OTDevices`	`summarize`
`Onboarded`	`summarize`
`Servers`	`summarize`
`Workstations`	`summarize`
`set_DeviceObj`	`extend`
`CountIPs`	`extend`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Hunt for devices organized by subnet

References

Rule body yaml

Stages and Predicates

Parameters

Let binding: `isolationSupportedOS`

Let binding: `base`

Let binding: `networks`

Let binding: `device_with_host_prefix`

Let binding: `network_addresses`

Let binding: `networks2`

union (2 sources)

Leg 1: `networks`

Leg 2: `networks2`

Applied to the combined result

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

Hunt for devices organized by subnet

References

Rule body yaml

Stages and Predicates

Parameters

Let binding: isolationSupportedOS

Let binding: base

Let binding: networks

Let binding: device_with_host_prefix

Let binding: network_addresses

Let binding: networks2

union (2 sources)

Leg 1: networks

Leg 2: networks2

Applied to the combined result

Exclusions

Indicators

Output fields

Let binding: `isolationSupportedOS`

Let binding: `base`

Let binding: `networks`

Let binding: `device_with_host_prefix`

Let binding: `network_addresses`

Let binding: `networks2`

Leg 1: `networks`

Leg 2: `networks2`