Windows defender is having a lot of problems.
So I have a Microsoft 365 Family subscription, and Dark Web Monitoring shows 0 monitored items. SSN verification fails and advises you to contact support. I was also unable to delete the monitored information. I’m receive the error "Something went wrong, try again in a bit." The issue occurs in the Microsoft Defender app, web portal, and across devices. Is there anyway that I can get help with this?
Microsoft Defender for Office 365 Plan 1 is now rolling out to Microsoft 365 E3 and Office 365 E3
Starting today, Microsoft Defender for Office 365 Plan 1 is rolling out to customers with Microsoft 365 E3/G3 and Office 365 E3/G3 licenses, with rollout expected to complete by Fall 2026. For security teams, this means added protection against phishing, malware, and malicious links across email and collaboration, without needing to purchase or deploy a separate email security solution. It also means some protections will turn on automatically, so now is the right time to review your configuration and prepare for any changes to mail flow, policies, and end-user experience. What E3 customers are getting Previously, these subscriptions included built-in security to help filter spam and known malware. Defender for Office 365 Plan 1 builds on that foundation with additional protections designed to catch more sophisticated phishing attempts, malicious links, and zero-day threats, while giving your team better visibility into what is happening in your environment. Safe Links: Helps protect users with time-of-click protection by checking URLs and blocking malicious destinations, including QR code-based attacks. Safe Attachments: Helps stop unknown and zero-day malware before harmful files reach users. Advanced anti-phishing: Helps detect impersonation attacks that target your users, executives, and trusted domains. Expanded visibility and reporting: Gives security teams more actionable detections, alerts, and reporting in the Microsoft Defender portal. What changes automatically As the plan rolls out, protection will turn on automatically for licensed users. That is good news from a security perspective, but it is still important to understand what is changing in your environment. New protections can affect how messages are processed, how suspicious links are handled, what users see when they click blocked content, and how your team monitors and tunes policy settings after rollout. Read more about it here: https://learn.microsoft.com/en-us/defender-office-365/preset-security-policies#use-the-microsoft-defender-portal-to-add-exclusions-to-the-built-in-protection-preset-security-policy. How to prepare for the rollout Review your current mail flow and security configuration. If you know how mail is routed today and which protections are already in place, it will be easier to spot what changes once Defender for Office 365 Plan 1 is active. Decide how you want to manage policies. When the plan becomes available in your tenant, built-in protection is applied automatically for licensed users. If you want Microsoft recommended settings beyond that baseline, consider enabling the Standard or Strict preset security policies. Prepare your help desk and users. Users may start seeing warning or block experiences when Safe Links identifies a malicious destination. A simple heads-up can reduce confusion and support tickets. For more details and how to customize user notification, see Set up Safe Links policies. Plan for exceptions and tuning. If you have specific users, domains, or workflows that need exclusions, review those requirements early so your team is ready to adjust policies after rollout. Monitor what changes. Use the Microsoft Defender portal and Microsoft Secure Score to track new detections, review improvement actions, and prioritize follow-up configuration work. If you use a third-party secure email gateway If your organization routes email through a third-party secure email gateway such as Proofpoint, Mimecast, or Barracuda before it reaches Microsoft 365, you should review your configuration now. In many environments, it is recommended to configure Enhanced Filtering for Connectors, preserve original sender details in Exchange Online, and decide which service will handle link rewriting to avoid unnecessary overlap. If you are evaluating a broader consolidation of your email security stack, our guides on defense in depth and migration to Defender for Office 365 can help. Protection also extends to Microsoft Teams The plan also extends protection to Microsoft Teams chats and channels. That includes protection for shared links and files, post-delivery removal of malicious content, admin controls to manage enforcement, and user reporting to help your security team investigate suspicious messages faster. For practitioners, this adds another layer of coverage across the collaboration tools users rely on every day. Learn more For implementation guidance, visit the Microsoft Defender for Office 365 security documentation, review the step-by-step guides, and use the preset policy, defense in depth, migration, and connector configuration resources linked above to plan your rollout.
No way to automate restoring user‑reported emails after “no threats found”
When a user reports an email as phishing in Defender, the message gets moved to Deleted Items. After we triage it, if we mark it as “no threats found,” there’s no way to push it back to the user’s inbox as part of that workflow. That creates a bit of a broken experience: User is told the email is safe with our customized email response, but has to go find it themselves In a lot of cases they don’t (Outlook search won’t find it) We end up with follow‑ups like “where did it go?” Technically we could restore the email as part of our triage process, but that just shifts the effort onto the SOC. It doesn’t scale, and it’s not really the right place for that work. We have tried to create an automation to do this, but we have not been able to create an advanced hunting query based on our triage result that can then trigger an action to restore it to the mailbox. So we end up choosing between: Users having a bad experience, or Analysts doing manual mailbox work Neither is ideal. Other platforms (like Proofpoint) handle this end‑to‑end — once something is confirmed clean, it can be returned to the user automatically. Right now Defender stops at classification instead of completing the workflow. Is there a reason this isn’t wired in, or anything on the roadmap to address it?Sentinel to Defender Portal Migration - my 5 Gotchas to help you
The migration to the unified Defender portal is one of those transitions where the documentation covers "what's new" but glosses over what breaks on cutover day. Here are the gotchas that consistently catch teams off-guard, along with practical fixes. Gotcha 1: Automatic Connector Enablement When a Sentinel workspace connects to the Defender portal, Microsoft auto-enables certain connectors - often without clear notification. The most common surprises: Connector Auto-Enables? Impact Defender for Endpoint Yes EDR telemetry starts flowing, new alerts created Defender for Cloud Yes Additional incidents, potential ingestion cost increase Defender for Cloud Apps Conditional Depends on existing tenant config Azure AD Identity Protection No Stays in Sentinel workspace only Immediate action: Within 2 hours of connecting, navigate to Security.microsoft.com > Connectors & integrations > Data connectors and audit what auto-enabled. Compare against your pre-migration connector list and disable anything unplanned. Why this matters: Auto-enabled connectors can duplicate data sources - ingesting the same telemetry through both Sentinel and Defender connectors inflates Log Analytics costs by 20-40%. Gotcha 2: Incident Duplication The most disruptive surprise. The same incident appears twice: once from a Sentinel analytics rule, once from the Defender portal's auto-created incident creation rule. SOC teams get paged twice, deduplication breaks, and MTTR metrics go sideways. Diagnosis: SecurityIncident | where TimeGenerated > ago(7d) | summarize IncidentCount = count() by Title | where IncidentCount > 1 | order by IncidentCount desc If you see unexpected duplicates, the cause is almost certainly the auto-enabled Microsoft incident creation rule conflicting with your existing analytics rules. Fix: Disable the auto-created incident creation rule in Sentinel Automation rules, and rely on your existing analytics rule > incident mapping instead. This ensures incidents are created only through Sentinel's pipeline. Gotcha 3: Analytics Rule Title Dependencies The Defender portal matches incidents to analytics rules by title, not by rule ID. This creates subtle problems: Renaming a rule breaks the incident linkage Copying a rule with a similar title causes cross-linkage Two workspaces with identically named rules generate separate incidents for the same alert Prevention checklist: Audit all analytics rule titles for uniqueness before migration Document the title-to-GUID mapping as a reference Avoid renaming rules en masse during migration Use a naming convention like <Severity>_<Tactic>_<Technique> to prevent collisions Gotcha 4: RBAC Gaps Sentinel workspace RBAC roles don't directly translate to Defender portal permissions: Sentinel Role Defender Portal Equivalent Gap Microsoft Sentinel Responder Security Operator Minor - name change Microsoft Sentinel Contributor Security Operator + Security settings (manage) Significant - split across roles Sentinel Automation Contributor Automation Contributor (new) New role required Migration approach: Create new unified RBAC roles in the Defender portal that mirror your existing Sentinel permissions. Test with a pilot group before org-wide rollout. Keep workspace RBAC roles for 30 days as a fallback. Gotcha 5: Automation Rules Don't Auto-Migrate Sentinel automation rules and playbooks don't carry over to the Defender portal automatically. The syntax has changed, and not all Sentinel automation actions are available in Defender. Recommended approach: Export existing Sentinel automation rules (screenshot condition logic and actions) Recreate them in the Defender portal Run both in parallel for one week to validate behavior Retire Sentinel automation rules only after confirming Defender equivalents work correctly Practical Migration Timeline Phase 1 - Pre-migration (1-2 weeks before): Audit connectors, analytics rules, RBAC roles, and automation rules Document everything - titles, GUIDs, permissions, automation logic Test in a pilot environment first Phase 2 - Cutover day: Connect workspace to Defender portal Within 2 hours: audit auto-enabled connectors Within 4 hours: check for duplicate incidents Within 24 hours: validate RBAC and automation rules Phase 3 - Post-migration (1-2 weeks after): Monitor incident volume for duplication spikes Validate automation rules fire correctly Collect SOC team feedback on workflow impact After 1 week of stability: retire legacy automation rules Phase 4 - Cleanup (2-4 weeks after): Remove duplicate automation rules Archive workspace-specific RBAC roles once unified RBAC is stable Update SOC runbooks and documentation The bottom line: treat this as a parallel-run migration, not a lift-and-shift. Budget 2 weeks for parallel operations. Teams that rushed this transition consistently reported longer MTTR during the first month post-migration.Declutter and Defend: Reducing promotional mail noise with Microsoft Defender
Enterprise inboxes are overwhelmed with graymail — legitimate, bulk email like newsletters, vendor promotions, and product updates that isn't malicious but buries the messages that matter. When high volumes of these mails land in the inbox, it crowds out priority communications and can dull security vigilance. Employees conditioned to ignore repetitive emails may miss signs of a real threat. It also creates recurring work for admins and security teams who must continuously tune filters, manage exception requests, and chase noise from user reports for email that isn’t malicious. Because graymail passes every spam filter check, traditional defenses don't separate it — leaving this signal-to-noise gap unaddressed. Today we’re excited to announce that Microsoft Defender now includes built-in graymail filtering. It is delivered natively through a new Promotions experience in Outlook that automatically classifies and separates bulk email, so it no longer competes with business-critical communication in the inbox. Now in Public Preview, this capability learns from how users interact with graymail to become more accurate over time. Coupled with the existing Bulk Senders Insight report, Defender brings data-driven bulk classification and control into the security workflows you already use. What Is Graymail? Graymail is legitimate bulk email that isn't malicious—product newsletters, event announcements, marketing promotions, and software update notifications from reputable, authenticated senders. It is distinct from spam and from phishing - graymail comes from real organizations with proper authentication and traditional spam filters aren't designed to handle it. Graymail handling in Microsoft Defender Microsoft Defender's approach is built on three principles: classify intelligently, deliver natively, and learn continuously. Promotions Folder — Intelligent Inbox Organization A dedicated Promotions folder, natively provisioned in Outlook, now keeps legitimate bulk mail out of the primary inbox. Promotional content is separated from priority emails without being sent to Junk, which means users can still access and browse newsletters and updates at their own pace. The folder appears at the top level of the mailbox for easy discovery and is visible across all Outlook experiences. Non-spam bulk mail below the organization's configured Bulk Complaint Level threshold is automatically routed to the Promotions folder. Messages from senders the user has explicitly allowed continue to land in the Inbox. Messages identified as spam continue to go to Junk. To enable the Promotions folder administrators need to enable the "Bulk Moves Enabled" setting in their anti-spam policy. The Promotions folder is then created for all users and used for routing only when this setting is ON. Existing mail flow is unaffected. Promotional mail tagging and Mailbox Rule Support Messages classified as graymail will automatically be labeled with a "Promotions" system tag in Outlook. The tag provides instant visual context without requiring users to open each message and is visible in Outlook on the Web and the native Outlook desktop apps for Windows and Mac. During Public Preview, the tagging component is opt-in, requiring administrators to enable it by configuring an Exchange Transport Rule. Once generally available, it will be enabled by default. Because this classification is integrated at the client level, the Promotions tag can also be used as a condition in Outlook mailbox rules. This enables custom routing logic for advanced scenarios like moving all promotions-tagged messages from a specific sender to a custom folder, flagging certain promotional emails for follow-up, or auto-forwarding or deleting promotions that meet specific criteria. This transforms the Promotions classification from a one-way filter into a flexible building block for personal and organizational workflows—particularly valuable for power users and teams with compliance or archival requirements. Adaptive Learning Microsoft Defender's graymail filtering gets smarter with every interaction. The system learns directly from how users handle their mail. When a user moves a message out of the Promotions folder and back to the Inbox, future emails from that sender will no longer be placed in the Promotions folder. When a user moves a message from the Inbox into the Promotions folder, future emails from that sender will be routed to the Promotions folder automatically. This creates a personalized, self-improving experience that becomes more accurate over time - no manual rule configuration required, no safe-sender lists to maintain, and no filtering rules for IT teams to manage on behalf of individual employees. Built into existing Security Workflows Administrators also gain visibility through the Bulk Senders Insight report, which provides data-driven guidance on what your organization actually receives and can help tune your bulk mail filtering. Graymail has long been the unsolved middle ground of email security—too legitimate to block, too noisy to ignore. Microsoft Defender now handles it where it should be handled: inside the platform, inside the mailbox, and inside the security workflows your organization already relies on. No new portals, no new vendors, no compromise between security and user experience. Get Started Configure promotions tagging and the promotions folder today - Bulk email detection documentation on Microsoft Learn. Monitor the experience using the Bulk Senders Insight report.Granular email content access with unified RBAC – now the default for new Defender tenants
Email investigations are a key part of detecting and responding to phishing and malware. As security workflows continue to evolve, there is an increasing need to align email content visibility more closely with specific roles and scenarios, such as Tier‑1 analysis or specialized workflows like user‑reported phishing triage. Today we’re announcing additional “read-only” controls for more granular email access in Microsoft Defender and that starting on May 30 th , 2026, unified RBAC will become the new default for permission modeling for new tenants. Unified RBAC in Microsoft Defender: a single, consistent permissions model Microsoft Defender unified role‑based access control (RBAC) provides a centralized way to manage permissions across the Defender security portfolio, replacing the need to configure and audit access separately for each solution, including endpoint, identity, SaaS, Cloud, and more. Instead of stitching together service‑specific role models, unified RBAC gives security teams one consistent authorization framework to control what users can see and do across the Microsoft Defender portal. Unified RBAC is designed to support modern security operations by aligning access with real‑world roles, such as analysts, investigators, and administrators, while reducing the risk that comes from over‑permissioned accounts including: Enforcing least‑privilege access consistently Understanding who has access to sensitive data across services Performing clean access reviews and audits Scaling permissions safely in tiered SOC or partner‑managed environments Unified RBAC addresses these challenges by converging permissions into a single model and separates read-only (data access) and manage (action‑taking) permissions by design, making access intent explicit and reducing accidental overexposure of sensitive security data. More granular email permissions within unified RBAC Unified RBAC now supports additional read‑only permissions for specific email content scenarios—so access can be matched precisely to investigation and review workflows. 1. New permission-Email & collaboration content: Emails associated with alerts The new Emails associated with alerts permission allows analysts to preview or download emails only when they are directly associated with a security alert, without granting access to all email content. Initially, this permission applies to alerts of type Email reported by user as malware or phish and Email reported by user as junk, which is one of the most common investigation entry points for security teams. Only emails tied to that alert type can be previewed or downloaded. Support for additional alert types will expand in future updates. Why this matters: Tier‑1 analysts and triage teams can investigate user‑reported threats quickly and effectively, without being granted visibility into unrelated emails. 2. New permission- Email and Collaboration content: Quarantine Emails This new permission allows previewing and downloading only emails that are in admin quarantine, supporting roles responsible for reviewing or validating quarantined messages – without broader email access. Important: After this update, Email & collaboration quarantine and Security data basics will no longer provide email content preview or download by themselves. To allow content visibility for quarantined messages, you must explicitly assign Emails in Quarantine. This change clarifies role boundaries and simplifies audits by making content access intentional and explicit. Read more here. Why this matters: Quarantine review teams can access exactly what they need—no more, no less—supporting least-privilege access by design. These permissions extend the Unified RBAC model for email & collaboration by separating visibility from action. They allow security teams to grant targeted access to email content only where it’s required, while preserving full content access for senior investigators and incident response teams. Full email content access remains available through existing permissions—such as Email & collaboration content: All emails—for senior investigators and incident response teams who require unrestricted visibility. Unified RBAC becomes the default for new Microsoft Defender tenants Starting May 30 th , 2026, Unified RBAC will be enabled by default for new Microsoft Defender for Office 365 Plan 2 tenants, making it the primary permissions model that enables a single, unified authorization model across the Defender suite. Permissions are managed through Defender unified RBAC roles, alongside Microsoft Entra roles where applicable (e.g. for Attack Simulation Training). Making Unified RBAC the default for new tenants is a key step toward simplifying permissions management and embeds least-privilege access by design. Learn more Microsoft Defender Unified role-based access control (RBAC) Create custom roles with Microsoft Defender Unified role-based access control (RBAC) Manage quarantined messages and files as an admin The Email entity page in Defender for Office 365
Enable per‑user language selection for phishing simulation emails and landing pages
We use Attack Simulation Training to deliver phishing simulations to a global, multilingual user base. While Microsoft Defender supports multi‑language content, phishing simulation emails and landing pages are currently delivered in a single selected language per campaign. We are requesting a feature that allows phishing simulation emails and associated landing pages (including credential‑harvest pages) to automatically render in each user’s preferred language, based on: Outlook mailbox language settings, and/or Microsoft Entra ID user language preferences This capability would: Improve realism and accuracy of phishing simulations Ensure users experience simulations in the same language they normally work in Improve behavioral measurement in global organizations Reduce the need to create and manage multiple parallel simulations by language Providing consistent, per‑user language alignment across simulation emails, landing pages, and follow‑up training would significantly enhance the effectiveness of Attack Simulation Training for large, multilingual enterprises.Security Dashboard for AI - Now Generally Available
AI proliferation in the enterprise, combined with the emergence of AI governance committees and evolving AI regulations, leaves CISOs and AI risk leaders needing a clear view of their AI risks, such as data leaks, model vulnerabilities, misconfigurations, and unethical agent actions across their entire AI estate, spanning AI platforms, apps, and agents. 53% of security professionals say their current AI risk management needs improvement, presenting an opportunity to better identify, assess and manage risk effectively. 1 At the same time, 86% of leaders prefer integrated platforms over fragmented tools, citing better visibility, fewer alerts and improved efficiency. 2 To address these needs, we are excited to announce the Security Dashboard for AI, previously announced at Microsoft Ignite, is now generally available. This unified dashboard aggregates posture and real-time risk signals from Microsoft Defender, Microsoft Entra, and Microsoft Purview - enabling users to see left-to-right across purpose-built security tools from within a single pane of glass. The dashboard equips CISOs and AI risk leaders with a governance tool to discover agents and AI apps, track AI posture and drift, and correlate risk signals to investigate and act across their entire AI ecosystem. Security teams can continue using the tools they trust while empowering security leaders to govern and collaborate effectively. Gain Unified AI Risk Visibility Consolidating risk signals from across purpose-built tools can simplify AI asset visibility and oversight, increase security teams’ efficiency, and reduce the opportunity for human error. The Security Dashboard for AI provides leaders with unified AI risk visibility by aggregating security, identity, and data risk across Defender, Entra, Purview into a single interactive dashboard experience. The Overview tab of the dashboard provides users with an AI risk scorecard, providing immediate visibility to where there may be risks for security teams to address. It also assesses an organization's implementation of Microsoft security for AI capabilities and provides recommendations for improving AI security posture. The dashboard also features an AI inventory with comprehensive views to support AI assets discovery, risk assessments, and remediation actions for broad coverage of AI agents, models, MCP servers, and applications. The dashboard provides coverage for all Microsoft AI solutions supported by Entra, Defender and Purview—including Microsoft 365 Copilot, Microsoft Copilot Studio agents, and Microsoft Foundry applications and agents—as well as third-party AI models, applications, and agents, such as Google Gemini, OpenAI ChatGPT, and MCP servers. This supports comprehensive visibility and control, regardless of where applications and agents are built. Prioritize Critical Risk with Security Copilots AI-Powered Insights Risk leaders must do more than just recognize existing risks—they also need to determine which ones pose the greatest threat to their business. The dashboard provides a consolidated view of AI-related security risks and leverages Security Copilot’s AI-powered insights to help find the most critical risks within an environment. For example, Security Copilot natural language interaction improves agent discovery and categorization, helping leaders identify unmanaged and shadow AI agents to enhance security posture. Furthermore, Security Copilot allows leaders to investigate AI risks and agent activities through prompt-based exploration, putting them in the driver’s seat for additional risk investigation. Drive Risk Mitigation By streamlining risk mitigation recommendations and automated task delegation, organizations can significantly improve the efficiency of their AI risk management processes. This approach can reduce the potential hidden AI risk and accelerate compliance efforts, helping to ensure that risk mitigation is timely and accurate. To address this, the Security Dashboard for AI evaluates how organizations put Microsoft’s AI security features into practice and offers tailored suggestions to strengthen AI security posture. It leverages Microsoft’s productivity tools for immediate action within the practitioner portal, making it easy for administrators to delegate recommendation tasks to designated users. With the Security Dashboard for AI, CISOs and risk leaders gain a clear, consolidated view of AI risks across agents, apps, and platforms—eliminating fragmented visibility, disconnected posture insights, and governance gaps as AI adoption scales. Best of all, the Security Dashboard for AI is included with eligible Microsoft security products customers already use. If an organization is already using Microsoft security products to secure AI, they are already a Security Dashboard for AI customer. Getting Started Existing Microsoft Security customers can start using Security Dashboard for AI today. It is included when a customer has the Microsoft Security products—Defender, Entra and Purview—with no additional licensing required. To begin using the Security Dashboard for AI, visit http://ai.security.microsoft.com or access the dashboard from the Defender, Entra or Purview portals. Learn more about the Security Dashboard for AI at Microsoft Security MS Learn. 1AuditBoard & Ascend2 Research. The Connected Risk Report: Uniting Teams and Insights to Drive Organizational Resilience. AuditBoard, October 2024. 2Microsoft. 2026 Data Security Index: Unifying Data Protection and AI Innovation. Microsoft Security, 2026Microsoft Defender for Office 365: Fine-Tuning
In incident response, most business email compromise doesn’t start with “sophisticated zero-day malware.” It starts with configuration gaps: forwarding mail outside the tenant, users clicking through Safe Links warnings, impersonation policies left at day-one defaults, or post-delivery cleanup still relying on a human analyst at 2:00 AM. Those gaps are what attackers actually exploit. This blog covers our top recommendations for fine-tuning Microsoft Defender for Office 365 configuration from hundreds of deployments and recovery engagements: Core fine-tuning actions every email or security admin should land right now Data-driven bulk mail tuning (BCL and Bulk Mail Insights) Impersonation and anti-phishing policy hygiene for executive protection Automate post-delivery cleanup by enabling Automated Remediation Each section includes a short video and practical guidance you can apply immediately in Microsoft Defender for Office 365. These recommendations align with Microsoft’s “secure by default” direction: applying the Standard and Strict preset security policies to users, using Configuration analyzer to catch configuration drift, and enforcing least-privilege release of high-risk mail. When possible, enable the Preset security policies to give you Microsoft’s recommended settings for Safe Links, Safe Attachments, Anti-Phishing, and Anti-Spam. If you use custom policies (or if you exclude users from the Presets) then use Configuration analyzer regularly to compare custom policies to the Standard/Strict baselines, since those get updated as Microsoft updates the Preset policies. Core Fine-Tuning Checklist for Defender for Office 365 This section highlights six controls we recommend implementing broadly. These are “day one hardening” items we repeatedly validate with customers. Block automatic external forwarding by default Attackers often create hidden inbox rules that quietly forward mail (invoices, purchase orders, wire info) to an external account they control. Use outbound spam policies to block automatic external forwarding for the entire org and then create tightly scoped exceptions only for the handful of mailboxes that legitimately need it. This prevents data leakage and payment fraud scenarios where mail auto-forwards out of your tenant without anyone noticing. Although this setting is on by default (“System Controlled” means that external forwarding is disabled), we’ve found many tenants where this was disabled because the admin didn’t know how to create a custom policy for authorized forwarders. The trick is to order custom outbound policies to run as a higher priority than the default outbound policy which should be set to block auto-forwarded emails. It is a good idea to regularly review the auto forwarded message report (located in the Exchange Admin Center). Use Enhanced Filtering for Connectors (“skip listing”) when necessary If you’re routing inbound mail through a third-party Secure Email Gateway or an on-prem hop before Microsoft 365, Defender will see that intermediary as the source IP instead of the original sending IP, which degrades anti-spoofing effectiveness.Enhanced Filtering for Connectors — also called skip listing — lets Microsoft 365 look past that last hop and evaluate the real sending IP and headers, so SPF / DKIM / DMARC and anti-spam logic work correctly. This setting does not support centralized mail routing (unless the routing is linear; see the Enhanced Filtering for Connectors learn article), so make sure you are not using that before enabling Enhanced Filtering. Centralized routing is sometimes used by organizations running a hybrid Exchange deployment, connecting Exchange Online with an on-premises Exchange Server organization. Important: Do this instead of blanket SCL -1 transport rules that “bypass spam filtering for anything coming from our gateway.” Over-bypassing means phishing that slipped through the third-party filter can sail straight to user inboxes, which Microsoft specifically warns against. Turn on Safe Attachments protection beyond email (SharePoint, OneDrive, Teams) In the Safe Attachments “Global settings,” make sure Defender for Office 365 is set to protect files in SharePoint, OneDrive, and Microsoft Teams. When enabled, if a file is identified as malicious, Defender automatically locks the file in-place so users can’t open it in Teams or OneDrive. This gives you malware detonation and containment in collaboration channels, not just email. This step closes a gap we still see a lot: customers protect mail attachments well, but shared files and Teams chats are wide open. In the 1st part of this blog series, Microsoft MVP Purav Desai describes (here) how to prevent users from downloading malicious files by running a SharePoint PowerShell cmdlet: Set-SPOTenant -DisallowInfectedFileDownload $true Don’t let users click through Safe Links warnings Safe Links rewrites and time-of-click scans URLs in mail, Office apps, and Teams. In the Safe Links policy, clear “Let users click through to the original URL.” That prevents the classic “I know it says it’s malicious, but I really need to see it…” moment. Users get blocked instead of “warned but allowed.” This setting is also enforced in Microsoft’s Standard AND Strict preset security policies where click-through is explicitly disabled. Go beyond the default Common Attachment filter The anti-malware policy’s Common Attachment filter blocks known dangerous file extensions (executable content, scriptable content, etc.). Microsoft ships a default list (historically 50+ high-risk extensions), and you can customize it to block additional file types common in malware delivery, like HTML droppers or password-protected archives. Messages with those file types are treated as malware and quarantined. Do this centrally rather than relying on users to “spot a suspicious attachment.” Automation beats user judgment here. Use custom quarantine policies that require admin approval (instead of self-release) If you are not using the Preset Policies, you can create a quarantine policy to customize the user experience with quarantined messages. For anything phishing-related, I recommend creating a custom policy that allows the user to “request release from admin.” That means users can raise a hand if they think something should not have been quarantined, and an Incident is created for administrators to review before it is released. To me, this strikes the best balance between security and productivity. This keeps containment intact and gives the SOC final say. It also creates an auditable workflow: who asked for release, who approved it, and why. Bulk Mail Insights: Tune BCL using your tenant’s mail Bulk email (“graymail”) is noisy. Payroll alerts and benefits notifications are legitimate, but they look exactly like phishing. At the same time, true marketing email (graymail) are also bulk. The traditional response (“just whitelist the sender so users stop complaining”) often opens the door for attacker-looking mail to get delivered straight to executives. Defender for Office 365 gives you something better: Bulk Mail Insights (a.k.a. Bulk senders insight). This report shows, over the last 60 days, how much mail at each Bulk Complaint Level (BCL 1–9) was delivered vs. blocked, which senders are generating volume, and where users are likely to experience false positives or false negatives. You can interactively simulate raising or lowering the bulk threshold and immediately see, “If we tighten BCL, how many more messages get quarantined? How many of those were probably junk? How many were probably wanted?” Why this matters: You stop tuning bulk mail based on anecdotes and start tuning based on real telemetry from your own tenant. You can justify decisions to leadership and audit (“We set BCL at X because here is the simulation showing false positive/false negative impact”). You avoid blanket allow rules. Instead, you adjust bulk thresholds for legitimate high-volume senders while keeping stricter actions for everyone else. Note: You can modify the BCL threshold in your default or custom anti-spam policy, but you can’t change it inside the Standard (BCL:6) or Strict (BCL:5) preset security policies themselves. Standard and Strict are already aligned to Microsoft’s recommended baselines. Additional Links: https://security.microsoft.com/senderinsights https://learn.microsoft.com/en-us/defender-office-365/anti-spam-bulk-senders-insight https://learn.microsoft.com/en-us/defender-office-365/mdo-deployment-guide#step-2-configure-threat-policies https://learn.microsoft.com/en-us/defender-office-365/preset-security-policies#policy-settings-in-preset-security-policies https://learn.microsoft.com/en-us/defender-office-365/recommended-settings-for-eop-and-office365 https://www.microsoft.com/en-us/security/blog/2025/07/17/transparency-on-microsoft-defender-for-office-365-email-security-effectiveness/ Anti-Phishing / Impersonation Tuning: Protect the people attackers actually spoof Business email compromise very often looks like this: “Hi, can you handle this payment today?” sent from an address that looks like your CFO or CEO. Microsoft Defender for Office 365 includes targeted impersonation protection, but it only really works if you target your most targeted executives. Here are five pitfalls we see over and over: Empty or stale VIP list Populate “users to protect / high value targets” with executives, finance approvers, legal, anyone authorized to move money or data. Review it monthly. Roles change, and you only get a finite number of protected users (for example, ~350 entries). An out-of-date list silently weakens protection for the people attackers actually impersonate. Phishing email threshold stuck at 1 forever We find organizations that are not using the preset policies have left their phishing threshold values at the default “1” because of initial false positives. We recommend raising it to match the Standard Preset (“3”) or Strict (“4”). Weak action If suspicious “CFO” mail just goes to Junk, users can still act on it. High-confidence impersonation of executives should be quarantined with AdminOnly or request-release workflows, not left in end-user control. Tie this back to the custom quarantine policies (discussed later in this article). Common-name overload If your CEO’s name is something extremely common, you’ll get noise. Expect it. Don’t “turn off” protection for that name — add that address to the Trusted Senders otherwise it will be blocked as an impersonation attempt. Use Trusted Senders / Trusted Domains for known-good partners and vendors so you keep protection high without drowning in alerts. Add only legitimate senders/domains to the Trusted Senders or Trusted Domains instead of lowering enforcement. No scheduled review This control can’t be “set and forget.” Put impersonation tuning and spoof intelligence review on a monthly checklist. That lets you catch new vendors pretending to be finance, new “urgent wire” lure patterns, and any drift from Standard / Strict baseline that Configuration analyzer will also call out. When done right, impersonation protection is not just “spam reduction.” It’s payment fraud prevention. Automated Investigation & Response (AIR): Let Defender remove malicious email before your SOC has to! One of the biggest wins you can land quickly is letting Microsoft Defender for Office 365 automatically remove clusters of malicious messages — without waiting for analyst approval on every single item. Here’s how it works. Defender’s Automated Investigation and Response (AIR) groups messages into “clusters” based on shared indicators like the same malicious URL or malicious file hash. If you opt in to automatic remediation for those cluster types, AIR will go find every matching copy of that threat across the tenant and soft-delete those messages, not just the one that triggered the alert. Why this matters: It turns post-delivery cleanup into something that happens immediately instead of “after Tier 1 has time to review.” It removes known-bad messages from user mailboxes (and related collaboration surfaces like Teams) before a target can click. It dramatically cuts the classic “Did anyone else get this?” manual hunt-and-purge work that burns out SOC analysts. When you configure AIR automation settings in the Microsoft Defender portal (Settings > Email & collaboration > MDO automation settings), you’ll see checkboxes for “Similar files” and “Similar URLs.” Selecting those opts you into automatic soft delete for those clusters. Today, soft delete is the default supported action for these automatic remediations, enabling administrators to undo a deletion, if necessary. This is Defender for Office 365 Plan 2 / Microsoft 365 E5 functionality, and it’s exactly the kind of “secure operations by default” Microsoft has been pushing: detect, contain, and clean up automatically, then let humans investigate with context instead of manually chasing every copy of a phish. This automation triggers when malicious clusters are detected. For automating the classification and triage of user-submitted phishing incidents, check out the Security Copilot Phishing Triage Agent (Preview). Additional Links: GA Announcement: https://techcommunity.microsoft.com/blog/-/auto-remediation-of-malicious-messages-in-automated/4418047 Docs: https://learn.microsoft.com/en-us/defender-office-365/air-auto-remediation Final Thoughts Defender for Office 365 is more than “email filtering.” It’s part of your security operations surface. The decisions you make about automated remediation (AIR), bulk mail thresholds, Safe Links/Attachment behavior, outbound forwarding, connector hygiene, quarantine policy, and impersonation tuning directly determine how easy — or how hard — it is for an attacker to penetrate your organization. Microsoft’s current guidance is clear: Apply Standard or Strict preset security policies so users get the recommended protections by default (for example, Safe Links with no click-through). If you must use a custom policy, review the recommendations from the Configuration analyzer monthly for new recommendations, or to catch and correct drift whenever someone weakens a control. Align internal procedures with the excellent Security Operations Guide for Defender for Office 365. Lock down quarantine so only admins can release high-risk messages, with an auditable “request release” path for users. Turn on automated remediation so Defender can remove malicious clusters of messages before anyone clicks. Organizations that land these basics are in a dramatically better position during an incident. Instead of “Who clicked the link?” you can say, “AIR already pulled it, users were blocked from clicking through, outbound forwarding is disabled, and impersonation of the CFO is quarantined for admin review.” That’s what “secure by default” actually looks like in production. ________ This blog was authored by Joe Stocker, Microsoft Security MVP and Founder of Patriot Consulting Technology Group, in partnership with the Microsoft Defender for Office 365 product team, including Paul Newell, Senior Product Manager, Microsoft Defender for Office 365. Joe Stocker Microsoft Security MVP Learn More and Meet the Author 1) December 16th Ask the Experts Webinar: Microsoft Defender for Office 365 | Ask the Experts: Tips and Tricks (REGISTER HERE) DECEMBER 16, 8 AM US Pacific You’ve watched the latest Microsoft Defender for Office 365 best practices videos and read the blog posts by the esteemed Microsoft Most Valuable Professionals (MVPs). Now bring your toughest questions or unique situations straight to the experts. In this interactive panel discussion, Microsoft MVPs will answer your real-world scenarios, clarify best practices, and highlight practical tips surfaced in the recent series. We’ll kick off with a who’s who and recent blog/video series recap, then dedicate most of the time to your questions across migration, SOC optimization, fine-tuning configuration, Teams protection, and even Microsoft community engagement. Come ready with your questions (or pre-submit here) for the expert Security MVPs on camera, or the Microsoft Defender for Office 365 product team in the chat! REGISTER NOW for 12/16. 2) Additional MVP Tips and Tricks Blogs and Videos in this Four-Part Series: Microsoft Defender for Office 365: Migration & Onboarding by Purav Desai Safeguarding Microsoft Teams with Microsoft Defender for Office 365 by Pierre Thoor You may be right after all! Disputing Submission Responses in Microsoft Defender for Office 365 by Mona Ghadiri (This post) "Microsoft Defender for Office 365: Fine-Tuning" by Joe Stocker Learn and Engage with the Microsoft Security Community Log in and follow this Microsoft Defender for Office 365 blog and follow/post in the Microsoft Defender for Office 365 discussion space. Follow = Click the heart in the upper right when you're logged in 🤍 Learn more about the Microsoft MVP Program. Join the Microsoft Security Community and be notified of upcoming events, product feedback surveys, and more. Get early access to Microsoft Security products and provide feedback to engineers by joining the Microsoft Customer Connection Community. Join the Microsoft Security Community LinkedIn
