The recent cyberattack against a major U.S. organization, now widely referred to as the Stryker attack, serves as a stark reminder that our management tools are often the most targeted assets. When an adversary compromises an endpoint management system like Microsoft Intune, they don’t just get a foothold; they get the keys to every device in the fleet.
CISA recently issued a clear warning that organizations must move beyond basic configurations to protect these systems. If your management plane is compromised, the very tools you use to deploy security become the tools used to deploy ransomware.
Securing the Management Plane
The first lesson from the Stryker attack is that standard multi-factor authentication is no longer enough. CISA urges organizations to enforce hardware-backed MFA for all accounts with access to the endpoint management system. Phishing-resistant methods like FIDO2 security keys are essential because they prevent the types of session hijacking that led to this breach.
Beyond authentication, the principle of least privilege must be applied strictly within the Entra ID and Intune portals. You should audit your administrative roles and ensure that no single user has more access than necessary. Using Privileged Identity Management to provide just-in-time access can significantly reduce the window of opportunity for an attacker who manages to compromise a consultant or admin credential.
Monitoring is the other half of this equation. You need to ensure that logs from Intune and Entra ID are being ingested into a security information and event management system. Look for unusual patterns, such as a sudden spike in new policy deployments or changes to compliance requirements, which could indicate an unauthorized actor is preparing the ground for a wider attack.
Hardening the Windows Client
Once the management plane is secured, the focus shifts to the endpoints themselves. Microsoft recommends a layered approach that integrates Intune policies with Microsoft Defender for Endpoint. One of the most effective ways to stop an attack in its tracks is by implementing Attack Surface Reduction rules. These rules target the specific behaviors that malware uses, such as launching executable content from email or office applications.
Tamper Protection is another critical setting that often gets overlooked. When enabled via Intune, it prevents local administrators or malicious software from disabling essential security features like real-time protection or behavior monitoring. In the Stryker incident, attackers attempted to blind the security team by turning off endpoint detection. Tamper Protection makes this much more difficult by ensuring that only the Intune service can modify these settings.
You should also ensure that EDR in block mode is enabled. This feature provides an extra layer of defense by allowing Defender for Endpoint to take action on malicious artifacts even if your primary antivirus didn’t catch them initially. It acts as a safety net that catches sophisticated threats based on post-execution behavior.
Compliance as a Gatekeeper
Your security policies are only as good as their enforcement. Microsoft suggests using Intune compliance policies as a prerequisite for accessing corporate resources. By tying conditional access to device compliance, you can ensure that only healthy, fully patched, and correctly configured devices can reach your data.
If a device is compromised or an attacker tries to roll back security settings, the device will fall out of compliance and be automatically cut off from the network. This creates a self-healing environment where the risk of lateral movement is minimized.
Why This Matters for Your Organization
The shift in the threat landscape means that we can no longer treat Intune as just a deployment tool. It is a security product that requires its own rigorous defense strategy. The cost of hardening your environment now is a fraction of the cost of a full-scale recovery effort.
As we look toward a future with more sophisticated automated attacks, the integration between management and security is your best defense. Start by auditing your MFA requirements and reviewing your ASR rule coverage. Testing these settings in a pilot group is the best way to move forward without disrupting business operations while significantly raising the bar for any would-be attacker.
This approach ensures that your infrastructure is built on a foundation of technical excellence and a clear alignment with modern security needs. By building robust, collaborative relationships between identity, security, and endpoint teams, you can create a resilient environment that stands up to the next generation of threats.
References
- Hardening Windows clients with Microsoft Intune and Defender for Endpoint
- CISA Urges Endpoint Management System Hardening After Cyberattack
