Detect Device Registration in CrowdStrike LogScale
Adversaries may register a device to an adversary-controlled account to establish persistence or escalate privileges. Devices may be registered in an MFA system (Duo, Okta) to bypass multi-factor authentication requirements, or registered in a device management system (Entra ID, Intune) to access sensitive data while bypassing conditional access policies. APT29 has enrolled attacker-controlled devices into compromised Azure AD tenants. Tools like AADInternals can automate device registration to Entra ID. Adversaries may also exploit self-enrollment workflows that require only a username and password for dormant or first-device scenarios.
MITRE ATT&CK
- Tactic
- Persistence Privilege Escalation
- Technique
- T1098 Account Manipulation
- Sub-technique
- T1098.005 Device Registration
- Canonical reference
- https://attack.mitre.org/techniques/T1098/005/
LogScale Detection Query
// T1098.005 — Device Registration Detection (CrowdStrike Falcon LogScale / CQL)
// Assumes Azure AD audit logs ingested via Falcon LogScale Azure integration
// with ECS-compatible field mapping
event.dataset = "azure.auditlogs"
| azure.auditlogs.operation_name = /^(Add device|Register device|Add registered owner to device|Add registered users to device|Update device|Enroll device)$/
| event.outcome = "success"
| groupBy(
[
azure.auditlogs.initiated_by.user.user_principal_name,
azure.auditlogs.initiated_by.user.ip_address
],
function=[
count(as=registrationCount),
collect(
field=azure.auditlogs.target_resources.0.display_name,
as=deviceNames
),
collect(
field=azure.auditlogs.initiated_by.app.display_name,
as=initiatingApps
),
min(field=@timestamp, as=firstSeen),
max(field=@timestamp, as=lastSeen)
]
)
| isKnownApp := if(
initiatingApps
= /(?i)microsoft intune|intune enrollment|azure active directory connect|microsoft authentication broker|^azure active directory$/,
"true",
"false"
)
| suspicionScore := if(isKnownApp = "false", 2, 0)
| suspicionScore := suspicionScore + if(registrationCount >= 3, 2, 0)
| case {
registrationCount >= 3 and isKnownApp = "false"
| alertReason := "Bulk registration by unexpected application" ;
registrationCount >= 3
| alertReason := "Bulk device registration (3+ devices in window)" ;
isKnownApp = "false"
| alertReason := "Device registration by unexpected application" ;
*
| alertReason := "Suspicious device registration"
}
| where suspicionScore > 0 or registrationCount >= 3
| sort(field=suspicionScore, order=desc)
| table(
[
azure.auditlogs.initiated_by.user.user_principal_name,
azure.auditlogs.initiated_by.user.ip_address,
registrationCount,
deviceNames,
initiatingApps,
suspicionScore,
alertReason,
firstSeen,
lastSeen
]
)Detects T1098.005 device registration abuse in CrowdStrike Falcon LogScale using Azure AD audit logs ingested via the Falcon LogScale Azure integration. Groups successful device registration operations by initiating user and IP address, then applies a two-factor suspicion score: +2 for initiating applications outside the known MDM allowlist, +2 for bulk registrations (3+ devices). The case statement derives a human-readable alertReason for analyst triage. Consistent with APT29 tradecraft and AADInternals-automated enrollment patterns.
Data Sources
Required Tables
False Positives & Tuning
- Corporate IT performing bulk device provisioning during onboarding waves or scheduled hardware refresh cycles using approved service accounts that may not exactly match the MDM allowlist regex
- Automated Intune enrollment pipelines where the initiating app display name varies slightly across tenant configurations (e.g. 'Microsoft Intune' vs 'Intune Company Portal')
- MSP or MSSP technicians performing device enrollment in customer Azure AD tenants via delegated admin portals using their own tenant app identity
- CrowdStrike Falcon sensor deployment scripts that trigger Azure AD device registration events as part of endpoint onboarding automation
Other platforms for T1098.005
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Register Device to Entra ID using AADInternals PowerShell Module
Expected signal: Azure AD AuditLogs: OperationName='Add device' with actor UPN, source IP, and DeviceName='TestDevice-AtomicTest'. Result='success'. The initiating app will appear as an unexpected application ID (not standard Intune). SigninLogs will show token acquisition event from the same session.
- Test 2MFA Device Enrollment on Dormant Account Using Only Password
Expected signal: Azure AD AuditLogs: OperationName='User registered security info' or 'User started security info registration' and 'Update user' with modified properties showing phoneAuthenticationMethod added. SigninLogs: ROPC flow authentication (non-interactive) from the test IP. Identity Protection may flag the ROPC sign-in as risky.
- Test 3Bulk Device Registration to Entra ID via Graph API
Expected signal: Azure AD AuditLogs: 5 separate 'Add device' events within ~10 seconds from the same actor UPN and IP address. Each event will have Result='success' and DeviceName='AtomicTestDevice-Bulk-{1-5}'. The rapid succession of registrations will be visible in the timestamp sequence.
- Test 4Register Device to Entra ID Using Existing PRT (Primary Refresh Token) via dsregcmd
Expected signal: Azure AD AuditLogs: OperationName='Add device' or 'Register device' with DeviceName matching the machine's hostname. Initiated by the currently logged-on user. Windows Event Log (System): Event ID 4648 or Events from Microsoft-Windows-User Device Registration source. Certificate created in CERT:\LocalMachine\My for the device.
References (14)
- https://attack.mitre.org/techniques/T1098/005/
- https://www.mandiant.com/resources/blog/apt29-continues-targeting-microsoft
- https://www.cisa.gov/uscert/ncas/alerts/aa22-074a
- https://o365blog.com/post/devices/
- https://o365blog.com/post/mdm
- https://o365blog.com/post/bprt/
- https://www.microsoft.com/security/blog/2022/01/26/evolved-phishing-device-registration-trick-adds-to-phishers-toolbox-for-victims-without-mfa
- https://www.microsoft.com/security/blog/2022/03/22/dev-0537-criminal-actor-targeting-organizations-for-data-exfiltration-and-destruction/
- https://learn.microsoft.com/en-us/entra/identity/devices/overview
- https://learn.microsoft.com/en-us/entra/identity/monitoring-health/reference-audit-activities
- https://expel.com/blog/observing-atlas-lion-part-one/
- https://www.darkreading.com/threat-intelligence/fireeye-s-mandia-severity-zero-alert-led-to-discovery-of-solarwinds-attack
- https://github.com/dirkjanm/ROADtools
- https://learn.microsoft.com/en-us/graph/api/device-post-devices
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