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Entra ID Device Registration with Phishing Kit Default OS Build

Identifies a Microsoft Entra ID device registration where the recorded cloud device operating system build is "10.0.19045.2006" and the device display name follows the default "DESKTOP-" pattern. This is the frozen…

Description

Identifies a Microsoft Entra ID device registration where the recorded cloud device operating system build is "10.0.19045.2006" and the device display name follows the default "DESKTOP-" pattern. This is the frozen default device profile observed when adversary-in-the-middle (AiTM) phishing kits such as Tycoon2FA and Kali365 register Azure AD-joined devices after capturing a victim session, in order to acquire a Primary Refresh Token (PRT) and establish persistence. The build is hardcoded by the tooling and it is uncommon for the OS build to match this exact value across an environment of otherwise patched hosts, where a current Windows 10 22H2 device reports a far higher "10.0.19045.<revision>" value.

Detection logic

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Detection requirements

Platform
ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows

The rule states no platform. This is derived from the ATT&CK technique it maps to.

Log source category
event_index

Known benign triggers

  • Authorized red team or penetration testing engagements that register devices with this OS profile will match this rule. If this is expected, add exceptions for the specific user principal names, source IPs, or device names involved.
  • Legitimate device registrations may coincidentally use the `10.0.19045.2006` build (Windows 10 22H2) with a default `DESKTOP-` hostname, particularly on imaged or unmanaged Windows hosts that have not been updated. Validate against your device inventory, expected provisioning workflows, and the registering user before escalating.

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