check before: 2025-09-01
Product:
Defender, Defender XDR
Platform:
Online, World tenant
Status:
Change type:
Feature update, Admin impact
Links:
Details:
Summary:
Starting September 2025, Microsoft Defender Antivirus will require the AVSignatureDue policy minimum to be 2 days (up from 1 day) to prevent false alerts. Organizations with settings below 2 days should update their configuration before rollout completes in mid-October 2025.
Details:
Introduction
To improve the accuracy of signature age alerts in Microsoft Defender Antivirus, we're updating the minimum supported value for the AVSignatureDue policy. Previously, this setting could be configured to as low as one day, which led to misleading alerts due to timing misalignment between signature updates and checks. Starting in September 2025, the minimum value will be set to 2 days.
When this will happen
General Availability (Worldwide): Rollout will begin in late September 2025 and is expected to complete by mid-October 2025.
Change Category:
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Scope:
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Release Phase:
Created:
2025-09-12
updated:
2025-09-12
Task Type
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Docu to Check
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MS How does it affect me
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MS Preperations
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MS Urgency
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summary for non-techies**
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Direct effects for Operations**
Increased False Alerts
With the AVSignatureDue policy set below 2 days, organizations will experience increased false alerts indicating outdated signatures, leading to confusion and potential security oversights.
- roles: IT Security Administrators, Help Desk Support
- references: https://learn.microsoft.com/microsoft-365/security/defender-endpoint/antivirus-policy-settings
Operational Disruption
Failure to update the AVSignatureDue policy may result in operational disruptions as security teams spend additional time addressing false alerts instead of focusing on real threats.
- roles: IT Security Administrators, Incident Response Teams
- references: https://learn.microsoft.com/microsoft-365/security/defender-endpoint/antivirus-policy-settings
User Experience Degradation
Users may experience degraded performance and trust in the security system due to frequent false alerts, leading to potential frustration and decreased productivity.
- roles: End Users, IT Support Staff
- references: https://learn.microsoft.com/microsoft-365/security/defender-endpoint/antivirus-policy-settings
Configutation Options**
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Opportunities**
Improved Alert Accuracy
By updating the AVSignatureDue policy to a minimum of 2 days, organizations can reduce the number of false alerts related to outdated signatures. This leads to a more reliable security posture and helps IT teams focus on genuine threats rather than being distracted by misleading alerts.
- next-steps: Review current AVSignatureDue policy settings and adjust them to meet the new minimum requirement of 2 days before the September 2025 deadline. Conduct training sessions for IT staff to ensure understanding of the new policy implications.
- roles: IT Security Team, System Administrators, Compliance Officers
- references: https://learn.microsoft.com/microsoft-365/security/defender-endpoint/antivirus-policy-settings
Operational Efficiency
Adjusting the AVSignatureDue policy can streamline IT operations by reducing the frequency of alerts that require investigation. This efficiency allows IT staff to allocate resources more effectively and prioritize critical tasks.
- next-steps: Analyze the current alert response workflow to identify bottlenecks caused by false alerts. Implement changes to the alert management process to accommodate the new policy settings and enhance operational workflows.
- roles: IT Operations Managers, Helpdesk Support, Network Administrators
- references: https://learn.microsoft.com/microsoft-365/security/defender-endpoint/antivirus-policy-settings
Compliance and Policy Management
Ensuring that the AVSignatureDue policy is compliant with the new requirements can help organizations maintain a strong security framework and avoid potential compliance issues in the future. This proactive approach demonstrates a commitment to security best practices.
- next-steps: Conduct a compliance audit to ensure all systems are updated to reflect the new AVSignatureDue policy. Document the changes and prepare for any future compliance reviews or audits.
- roles: Compliance Officers, IT Governance, Risk Management Teams
- references: https://learn.microsoft.com/microsoft-365/security/defender-endpoint/antivirus-policy-settings
Potentional Risks**
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Data Protection**
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IT Security**
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Hypothetical Work Council Statement**
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DPIA Draft**
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explanation for non-techies**
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** AI generated content. This information must be reviewed before use.
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Last updated 3 weeks ago ago
