Full Report
Microsoft is testing a faster version of Quick Machine Recovery (QMR) and updated Smart App Control (SAC), allowing users to toggle it without requiring a Windows clean install. [...]
Analysis Summary
# Best Practices: Windows System Resiliency and Application Control Configuration
## Overview
These practices focus on leveraging updated Microsoft Windows features—specifically Quick Machine Recovery (QMR) and Smart App Control (SAC)—to enhance system resilience against boot failures (often due to driver/update issues) and to improve proactive application-level security, all while reducing operational overhead associated with reinstallation or complex configuration changes.
## Key Recommendations
### Immediate Actions
1. **Enable QMR Default Settings:** Ensure that for all critical endpoints, the "Quick machine recovery" and "Automatically check for solutions" options are enabled in Windows 11 System Recovery settings to run a **one-time QMR scan by default** upon detecting boot failure, preventing iterative, unnecessary scan loops.
2. **Verify Smart App Control Toggling:** Confirm that the latest operating system builds are deployed where *Smart App Control (SAC)* can be toggled on or off directly via the Windows Security center without necessitating a full OS clean install, allowing for rapid triage changes.
3. **Test Remote Recovery Functionality:** Conduct smoke tests to confirm that QMR executes successfully on several test machines experiencing simulated boot failures (e.g., intentionally rolling back a critical driver) to validate remote data reporting and fix application mechanisms.
### Short-term Improvements (1-3 months)
1. **Mandate QMR Pre-Test:** Incorporate running QMR checks (or simulated failures leading to QMR activation) into the standard Operating System update validation checklists before widespread deployment of major feature updates or driver packages.
2. **Standardize SAC Deployment:** For all newly provisioned or imaged systems, configure Smart App Control to be **enabled** during the initial setup process to enforce application whitelisting from the first boot.
3. **Establish QMR Monitoring Baseline:** Begin logging QMR activation events and outcomes (successful fix rate, time to recovery) to establish a baseline for MTTR (Mean Time To Recovery) related to boot failures.
### Long-term Strategy (3+ months)
1. **Integrate QMR with Incident Response (IR):** Formalize procedures within the Incident Response framework to leverage QMR's remote diagnostic capabilities immediately following wide-scale configuration-related boot incidents (e.g., mass application of a problematic patch).
2. **Risk-Based SAC Policy Development:** For environments requiring specific legacy applications, develop a standardized, audited process for creating exceptions within Smart App Control policies, ensuring necessary apps are correctly signed or allowed via low-friction configuration methods before whitelisting becomes a bottleneck.
3. **Proactive Memory Diagnostics:** Investigate and plan the rollout of OS builds that prompt users for memory scans following Blue Screen of Death (BSOD) events to preemptively address potential hardware instability contributing to system crashes.
## Implementation Guidance
### For Small Organizations
- **Focus on Defaults:** Since IT staff resources are limited, rely heavily on the default settings of QMR (one-time scan enabled) and SAC. Ensure all endpoints are running the latest stable build supporting these out-of-the-box resilient features.
- **Manual Toggling:** Implement a policy requiring administrative staff to periodically check Windows Security to ensure SAC remains enabled unless an explicit, documented security risk assessment dictates temporary disabling.
### For Medium Organizations
- **Centralized Configuration:** Utilize Group Policy Objects (GPO) or Microsoft Endpoint Manager (Intune) to centrally manage the default enabling state of both QMR recovery diagnostics and Smart App Control enforcement across targeted organizational units.
- **Tiered SAC Rollout:** Roll out Smart App Control in phases (e.g., IT department first, then low-risk users, then high-risk users) to manage the administrative load of exception requests.
### For Large Enterprises
- **Automated Remediation Orchestration:** Integrate QMR success/failure reporting into existing orchestration tools (SCCM/MECM, dedicated RMM) to trigger automated follow-up actions (e.g., automatically rolling back the last update if QMR reports a fix based on an update exclusion).
- **Security Exception Gate:** Establish a formal Change Advisory Board (CAB) or equivalent gate for granting exceptions to the Smart App Control policy, ensuring that any application bypassing SAC is justified and time-bound.
## Configuration Examples
Since the article specifies the *change* in functionality rather than the initial setup commands, the primary guidance is enforcing the desired state via known Windows management tools:
1. **Enabling QMR (Assuming Insider/Future OS Stable Build):**
* **Path:** Settings > System > Recovery > System Recovery > Quick machine recovery & automatically check for solutions.
* **Action:** Ensure both toggles are set to **On**. (The update ensures the default behavior shifts to a one-time scan).
2. **Managing Smart App Control (SAC) via Policy (Example using Intune/GPO context):**
* **Configuration Goal:** Set SAC to Enforcement/Audit Mode.
* **Intune/Policy Setting:** Configure the relevant Microsoft Defender Application Control policy to enforce application blocking based on established baselines or audit mode before switching to full enforcement. The key benefit highlighted is the ease of *toggling* this setting later if required for troubleshooting without full reinstall.
## Compliance Alignment
| Standard | Relevant Area | Alignment Rationale |
| :--- | :--- | :--- |
| **NIST SP 800-53 Rev. 5** | RA-5 (Risk Assessment) | QMR allows for rapid assessment and mitigation of risks introduced by updates causing system instability. |
| **NIST SP 800-53 Rev. 5** | SC-32 (Application Whitelisting) | Smart App Control directly enforces application control policies, foundational to limiting unauthorized executable execution. |
| **ISO 27001** | A.12.1.2 (Change Management) | QMR reduces the impact of failed changes (updates/drivers), improving the robustness of the change process contingency plans. |
| **CIS Benchmarks (Windows 11)** | Control 3 & 4 (Application Software) | SAC aligns with mandatory application control and execution restriction controls. |
## Common Pitfalls to Avoid
1. **Assuming Universal Availability:** Do not deploy QMR/SAC configuration policies widely until the specific Windows build containing these finalized, non-Insider features is released to General Availability (GA).
2. **Ignoring QMR Failures:** Do not treat a QMR failure (where the automated fix is unavailable) as an endpoint success. These failures indicate a high-severity problem requiring immediate Level 2/3 manual IT intervention, as the device is still unbootable.
3. **Over-reliance on SAC Default:** While SAC is potent, do not enable it without first establishing clear support workflows for legitimate, signed business applications that might initially be blocked upon activation.
4. **Bypassing QMR for Troubleshooting:** Avoid manually deciding to reimage a system presenting a boot failure *before* allowing the remote QMR process to run, as this negates the invested time in developing faster remote recovery tools.
## Resources
- Microsoft Documentation on Quick Machine Recovery (QMR) (Search for "Quick Machine Recovery Windows documentation")
- Microsoft Documentation on Smart App Control (Search for "Smart App Control Windows Security")
- Windows Insider Blog for the specific build mentioned (KB5070300) for feature validation.