Account Manipulation: Device Registration

Adversaries may register a device to an adversary-controlled account. Devices may be registered in a multifactor authentication (MFA) system, which handles authentication to the network, or in a device management system, which handles device access and compliance.

MFA systems, such as Duo or Okta, allow users to associate devices with their accounts in order to complete MFA requirements. An adversary that compromises a user’s credentials may enroll a new device in order to bypass initial MFA requirements and gain persistent access to a network.[1][2] In some cases, the MFA self-enrollment process may require only a username and password to enroll the account's first device or to enroll a device to an inactive account. [3]

Similarly, an adversary with existing access to a network may register a device to Azure AD and/or its device management system, Microsoft Intune, in order to access sensitive data or resources while bypassing conditional access policies.[4][5][6]

Devices registered in Azure AD may be able to conduct Internal Spearphishing campaigns via intra-organizational emails, which are less likely to be treated as suspicious by the email client.[7] Additionally, an adversary may be able to perform a Service Exhaustion Flood on an Azure AD tenant by registering a large number of devices.[8]

ID: T1098.005
Sub-technique of:  T1098
Platforms: Azure AD, SaaS, Windows
Contributors: Arad Inbar, Fidelis Security; Joe Gumke, U.S. Bank; Mike Moran; Pawel Partyka, Microsoft 365 Defender
Version: 1.2
Created: 04 March 2022
Last Modified: 03 October 2023

Procedure Examples

ID Name Description
S0677 AADInternals

AADInternals can register a device to Azure AD.[9]

G0016 APT29

APT29 has enrolled a device in MFA to an Azure AD environment following a successful password guessing attack against a dormant account.[3]

C0027 C0027

During C0027, Scattered Spider registered devices for MFA to maintain persistence through victims' VPN.[10]

C0024 SolarWinds Compromise

During the SolarWinds Compromise, APT29 registered devices in order to enable mailbox syncing via the Set-CASMailbox command.[11]

Mitigations

ID Mitigation Description
M1032 Multi-factor Authentication

Require multi-factor authentication to register devices in Azure AD.[7] Configure multi-factor authentication systems to disallow enrolling new devices for inactive accounts.[1] When first enrolling MFA, use conditional access policies to restrict device enrollment to trusted locations or devices, and consider using temporary access passes as an initial MFA solution to enroll a device.[3]

Detection

ID Data Source Data Component Detects
DS0026 Active Directory Active Directory Object Creation

Monitor for the registration or joining of new device objects in Active Directory. Raise alerts when new devices are registered or joined without using MFA.[12]

DS0015 Application Log Application Log Content

Azure AD creates several log entries when new devices are enrolled, which can be monitored for unexpected device registrations.[8] Additionally, joined devices can be viewed via the Azure AD portal.[13]

DS0002 User Account User Account Modification

Monitor user accounts for new and suspicious device associations, such as those originating from unusual sources, occurring at unusual times, or following a suspicious login.[6]

References