↳ GitHub sourceAnalytics ruleHigh

Tailscale: Tailnet lock validation failed

Description

Identifies tailnet devices with a non-empty TailnetLockError, indicating the device failed tailnet-lock cryptographic validation. Suspicious - likely an unsigned node attempting to join.

Rule type: Scheduled
Version: 1.0.0
Declared status: Available
Query frequency: 1h
Query period: 1h
Trigger: gt 0

Declared MITRE coverage

Declared sources

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

Connectors

TailscaleCCF

Data types

Tailscale_Devices_CL

KQL query

Original query, unchanged.

Tailscale_Devices_CL
| where TimeGenerated > ago(1h)
| summarize arg_max(TimeGenerated, *) by DeviceId
| where isnotempty(TailnetLockError)
| project TimeGenerated, DeviceName, Hostname, User, Os, ClientVersion, TailnetLockError, TailnetLockKey, LastSeen, Authorized

Declared entities

HostAccount

Source provenance

GitHub

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

File: Solutions/Tailscale (CCF)/Analytic Rules/TailscaleTailnetLockValidationFailed.yaml ↗
Commit: 9800e51 ↗
Source identifier: e9f0a1b2-3456-7890-12cd-ef1234560040

Additional source files 2

Solutions/Tailscale (CCF)/Analytic Rules/TailscaleTailnetLockValidationFailed.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.