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Tailscale: External (shared-in) device added

Description

Identifies new external (shared-in) devices joining the tailnet that were not present in the prior 24-hour baseline. Each shared-in device expands the trust boundary - confirm the share matches a documented agreement and ACL scope.
Rule type
Scheduled
Version
1.0.0
Declared status
Available
Query frequency
1h
Query period
2d
Trigger
gt 0

Declared MITRE coverage

Declared sources

Metadata from the source file. No dependencies inferred from KQL.

Connectors

Data types

KQL query

Original query, unchanged.

let recent =
    Tailscale_Devices_CL
    | where TimeGenerated > ago(1h)
    | summarize arg_max(TimeGenerated, *) by DeviceId
    | where IsExternal == true
    | project DeviceId, DeviceName, Hostname, User, Os, ClientVersion, Created, LastSeen, Tags;
let prior =
    Tailscale_Devices_CL
    | where TimeGenerated between (ago(2d) .. ago(1h))
    | summarize arg_max(TimeGenerated, *) by DeviceId
    | where IsExternal == true
    | distinct DeviceId;
recent
| join kind=leftanti prior on DeviceId
| project TimeGenerated = now(), DeviceName, Hostname, User, Os, ClientVersion, Created, LastSeen, Tags

Declared entities

HostAccount

Related content

Links established from declared identifiers and solution manifests.

Source provenance

GitHub

Displayed values come from files in Azure/Azure-Sentinel. They describe the published template, not your workspace configuration.

Source identifier
b2c3d4e5-6789-0123-4567-890123450043
Additional source files 2Solutions/Tailscale (CCF)/Analytic Rules/TailscaleExternalDeviceAdded.yamlsource ↗Solutions/Tailscale (CCF)/Data/Solution_Tailscale.jsonsolution-membership ↗
GSTEP / CATALOG TRACKING

Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC

GSTEP sync dates, separate from the source content’s publication dates.