Protection Against Email Bombs with Microsoft Defender for Office 365
In today's digital age, email remains a critical communication tool for businesses and individuals. However, with the increasing sophistication of cyberattacks, email security has become more important than ever. One such threat that has been growing is the email bombing, a form of net abuse that sends large volumes of email to an address to overflow the mailbox, overwhelm the server, or distract attention from important email messages indicating a security breach. Email bomb - Wikipedia Understanding Email Bombing Email bombing, typically involves subscribing victims to a large number of legitimate newsletter and subscription services. Each subscription service sends email notifications, which in aggregate create a large stream of emails into the victim’s inbox, making email triage for legitimate emails very difficult. This form of attack is essentially a denial-of-service (DDOS) on the victim's email triaging attention budget. Hybrid Attacks More recently, email subscription bombs have been coupled with simultaneous lures on Microsoft Teams, Zoom, or via phone calls. Attackers impersonate IT support and offer to help solve the email problem caused by the spike of unwanted emails, ultimately compromising the victim's system or installing malware on their system. This type of attack is brilliant because it creates a sense of urgency and legitimacy, making victims more likely to accept remote assistance and inadvertently allow malware planting or data theft. Read about the use of mail bombs where threat actors misused Quick Assist in social engineering attacks leading to ransomware | Microsoft Security Blog. Incidence and Purpose of Email Bombing Email bombing attacks have been around for many years but can have significant impacts on targeted individuals, such as enterprise executives, HR or finance representatives. These attacks are often used as precursors to more serious security incidents, including malware planting, ransomware, and data exfiltration. They can also mute important security alerts, making it easier for attackers to carry out fraudulent activities without detection. New Detection technology for Mail Bombing attacks To address these types of attacks Microsoft Defender has now released a comprehensive solution involving a durable block to limit the influx of emails, the majority of which are often spam. By intelligently tracking message volumes across different sources and time intervals, this new detection leverages historical patterns of the sender and signals related to spam content. It prevents mail bombs from being dropped into the user’s inbox and the messages are rather sent to the Junk folder (of Outlook). Note: Safe sender lists in Outlook continue to be honored, so emails from trustworthy sources are not unexpectedly moved to the Junk folder (in order to prevent false positives). Since the initial rollout that started in early May, we’ve seen a tremendous impact in blocking mail bombing attacks out of our customers’ inboxes: How to leverage new “Mail bombing” detection technology in SOC experiences 1. Investigation and hunting: SOC analysts can now view the new Detection technology as Mail bombing within the following surfaces: Threat Explorer, Email entity page and Advanced Hunting empowering them to investigate, filter and hunt for threats related to mail bombing. 2. Custom detection rule: To analyze the frequency and volume of attacks from mail bombing vector, or to have automated alerts configured to notify SOC user whenever there is a mail bombing attack, SOC analysts can utilize the custom detection rules in Advanced hunting by writing a KQL query using data in DetectionMethods column of EmailEvents table. Here’s a sample query to get you started: EmailEvents | where Timestamp > ago(1d) | where DetectionMethods contains "Mail bombing" | project Timestamp, NetworkMessageId, SenderFromAddress, Subject, ReportId The SOC experiences are rolled out worldwide to all customers. Conclusion Email bombs represent an incidental threat in the world of cybersecurity. With the new detection technology for Mail Bombing, Microsoft Defender for Office 365 protects users from these attacks and empowers Security Operations Center Analysts to ensure to gain visibility into such attacks and take quick actions to keep organizations safe! Note: The Mail bombing protection is available by default in Exchange Online Protection and Microsoft Defender for Office 365 plans. This blog post is associated with Message Center post MC1096885. Also read Part 2 of our blog series to learn more about protection against multi-modal attacks involving mail bombing and correlation of Microsoft Teams activity in Defender. Watch this video to learn more: Microsoft Defender for Office 365 | Mail Bombing and Mixed-Mode Attack Protection Learn: Detection technology details table What's on the Email entity page Filterable properties in the All email view in Threat ExplorerYou may be right after all! Disputing Submission Responses in Microsoft Defender for Office 365
Introduction As a Microsoft MVP (Most Valuable Professional) specializing in SIEM, XDR, and Cloud Security, I have witnessed the rapid evolution of cybersecurity technologies, especially those designed to protect organizations from sophisticated threats targeting email and collaboration tools. Microsoft Defender for Office 365 introduced an LLM-based engine to help better classify phishing emails that, these days, are mostly written using AI anyways about a year ago. Today, I'm excited to spotlight a new place AI has been inserted into a workflow to make it better…a feature that elevates the transparency and responsiveness of threat management: the ability to dispute a submission response directly within Microsoft Defender for Office 365. Understanding the Challenge While the automated and human-driven analyses are robust in Defender for Office 365, there are occasions where the response—be it a verdict of "benign" or "malicious"— doesn’t fully align with the security team's context or threat intelligence. If you are a Microsoft 365 organization with Exchange Online mailboxes, you’re probably familiar with how admins can use the Submissions page in the Microsoft Defender portal to submit messages, URLs, and attachments to Microsoft for analysis. As a recent enhancement, now all the admin submissions use LLM based response for better explainability. In the past, disputing such verdicts required separate support channels, using Community support, or manual email processes, often delaying resolution and impacting the speed of cyber operations. Introducing the Dispute Submission Response Feature With the new dispute submission response feature, Microsoft Defender for Office 365 bridges a critical gap in the incident response workflow. Now, when a security analyst or administrator receives a verdict on a submitted item, they have the option to dispute the response directly within the Microsoft 365 Defender portal. This feature streamlines feedback, allowing teams to quickly flag disagreements and provide additional context for review at the speed of operations. How It Works Upon submission of a suspicious item, Microsoft Defender for Office 365 provides a response indicating its assessment—malicious, benign, or other categorizations. If the security team disagrees with the verdict, they can select the "Dispute" option and submit their rationale, including supporting evidence and threat intelligence. The disputed case is escalated directly to Microsoft’s threat research team for further review, and the team is notified of progress and outcomes. This direct feedback loop not only empowers security teams to advocate for their organization's unique context, but also enables Microsoft to continually refine detection algorithms and verdict accuracy based on real-world input, because security is a team sport. Benefits for Security Operations Faster Resolution: Streamlined dispute submission eliminates the need for external support tickets and escalations, reducing turnaround time for critical cases. Greater Transparency: The feature fosters a collaborative relationship between customers and Microsoft, ensuring that verdicts are not final judgments but points in an ongoing dialogue. Continuous Improvement: Feedback from disputes enhances Microsoft’s threat intelligence and improves detection for all Defender for Office 365 users. Empowerment: Security teams gain a stronger voice in the protection of their environment, reinforcing trust in automated defenses. MVP Insights: Real-World Impact Having worked with global enterprises, I’ve seen how nuanced and context-specific threats can be. Sometimes, what appears benign to one organization may be a targeted attack for another, a slight modification to a URL may catch one email, but not others, as slight changes are made as billions of emails are sent. We are only as good as the consortium. The ability to dispute submission responses creates a vital safety net, ensuring that security teams are not forced to accept verdicts that could expose them to risk. It’s a welcome step toward adaptive, user-driven security operations. Conclusion The dispute submission response feature in Microsoft Defender for Office 365 is one of the most exciting features for me, because it focuses on enabling organizations striving for agility and accuracy in threat management. By enabling direct, contextual feedback, Microsoft empowers security teams to play an active role in shaping their defenses. As an MVP, I encourage all users to leverage this feature, provide detailed feedback, and help drive the future of secure collaboration in the cloud. You may be right after all. _________ This blog has been generously and expertly authored by Microsoft Security MVP, Mona Ghadiri with support of the Microsoft Defender for Office 365 product team. Mona Ghadiri 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: 1. Microsoft Defender for Office 365: Migration & Onboarding by Purav Desai 2. Safeguarding Microsoft Teams with Microsoft Defender for Office 365 by Pierre Thoor 3. (This blog post) You may be right after all! Disputing Submission Responses in Microsoft Defender for Office 365 by Mona Ghadiri 4. Microsoft Defender for Office 365: Fine-Tuning | Real-world Defender for Office 365 tuning that closes real attack paths 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 LinkedInMicrosoft Ignite 2025: Transforming Phishing Response with Agentic Innovation
Phishing attacks remain one of the most persistent and damaging threats to organizations worldwide. Security teams are under constant pressure to investigate a growing number of user reported phishing emails daily, ensuring accurate verdicts and timely responses. As threats grow in volume and sophistication, SOC teams are forced to spend valuable time triaging and investigating, often at the expense of strategic defense and proactive threat hunting. At Microsoft Ignite 2025 we are delivering innovation that showcases our continued commitment to infuse AI agents, and agentic workflows into the core of our email security solution and SOC operations to automate repetitive tasks, accelerate investigations, and provide transparent, actionable insights for every reported phishing email. In addition, we continue to invest in our ecosystem partnerships to empower customers with seamless integrations, as they adopt layered security solutions to comply with regulatory requirements, enhance detection, and ensure robust protection. Today I’m excited to announce: General Availability of the Security Copilot Phishing Triage Agent Agentic Email Grading System in Microsoft Defender Cisco and VIPRE Security Group join the Microsoft Defender ICES ecosystem The Security Copilot Phishing Triage Agent is now generally available In March 2025, we introduced the Phishing Triage Agent, designed to autonomously handle user-submitted phishing reports at scale. The agent classifies incoming alerts, resolves false positives, and escalates only the malicious cases that require human expertise. Today, we’re announcing its general availability. We will also be extending the agent to triage alerts for identity and cloud alerts. The Phishing triage agent automates repetitive tasks, accelerates investigations, and every decision is transparent, allowing security teams to focus on what matters most—investigating real threats and strengthening the overall security posture. Early results prove how it is transforming analyst work: Identified 6.5X more malicious alerts Improved verdict accuracy by 77% Agent supported analysts spent 53% more time investigating real threats Agentic email grading: Advanced analysis of phishing email submissions When customers report suspicious messages to Microsoft, they expect clarity, speed, and actionable insights to protect their environment. They expect a response they can trust, understand easily, and take additional investigation and response action for the organization. Previously, when customers reported messages to Microsoft, our response depended largely on manual human grader reviews, creating delays and inconsistent verdicts. Customers often waited several hours for a response, and sometimes it lacked clarity on how a verdict was reached. Today, we are excited to announce that we integrated an agentic grading system into the Microsoft Defender submission analysis and response workflow when customers report phishing messages to Microsoft. Image 2: Agentic Email Grading: Advanced analysis of phishing email submissions The agentic grading system brings a new level of speed and transparency to phishing analysis. It uses large language models (LLMs) orchestrated within an agentic workflow to analyze phishing emails, assess the full content of a submitted email, and communicate context and related metadata. This system combines advanced AI with existing machine learning models and human review for additional levels of accuracy and transparency for decision making. Every verdict comes with higher quality, clear verdicts, and context-rich explanations tailored to each phishing email submission. Additionally, it establishes a feedback mechanism that enhances continuous learning and self-healing, thereby strengthening and optimizing protection over time. By reducing reliance on manual reviews, users will experience lower wait times, faster responses and higher-quality results. It will enable security teams to respond promptly and act confidently against phishing threats. Over time we plan to expand beyond phishing verdicts to include spam, scam, bulk, and clean classifications, making the process more comprehensive. The system will continue to evolve through feedback and adapt to emerging attack patterns. How to view agentic submission responses in Microsoft Defender When you report a suspicious email—whether as an admin or an end user—you can now see how Microsoft Defender’s new agentic grading system evaluates your submission. To view agentic grading system responses, follow the steps below: Report the suspicious email Submit the email through the admin submission or user-reported submission process. Sign in to Microsoft Defender Go to https://security.microsoft.com. Navigate to Submissions From the left menu, select: Investigation & response > Actions & submissions > Submissions. Choose the correct tab Emails for admin submissions User reported for user submissions Open the submission details Click the email submission you want to review. A flyout panel will display Result details. Look for the Agentic AI note If the verdict was generated by Agentic AI, you’ll see: “AI-generated content may be incorrect. Check it for accuracy.” Image 3: AI generated explainable verdicts Expanding the Integrated Cloud Email Security (ICES) ecosystem In June, we introduced the Microsoft Defender ICES vendor ecosystem, a unified framework that enables seamless integration of Microsoft’s Defender’s email security solution with trusted third-party vendors. Today we are excited to announce two new partners: Cisco and VIPRE Security Group. The addition of these partners to our ecosystem reinforces our ongoing commitment to support customers in their choice to strategically layer their email security solutions. Organizations benefit from a unified quarantine experience, and a deep integration across the various SOC experiences including threat explorer, advanced hunting, and the email entity page, while providing clear insight into detection efficacy of each solution. As we continue to innovate, our commitment remains steadfast: empowering defenders with intelligent, transparent, and integrated security solutions that adapt to the evolving threat landscape. By infusing agentic AI into every layer of Microsoft Defender, expanding our ecosystem of trusted partners, and delivering faster, more actionable insights, we’re helping organizations build resilience and stay ahead of attackers. Our strategy is rooted in delivering real value making security simpler, more effective, and adapted to the needs of every customer. Learn More: Want to know what else is new in Microsoft Defender at Ignite 2025 check out the blog here. For info on how to complete admin phish submissions, please see For end user reported phish submissions, you need to have it configured for reporting messages to Microsoft. Set it up today. Join us at Microsoft Ignite Join us at Microsoft Ignite to see these advancements in action and discover how intelligent, agentic defense is becoming accessible to every organization. Don’t miss our featured sessions: AI vs AI: Protect email and collaboration tools with Microsoft Defender on Thursday, November 20 th . Learn More. Microsoft Defender: Building the agentic SOC with guest Allie Mellen on Wednesday, November 19 th . Learn more. Empowering the SOC: Security Copilot and the rise of Agentic Defense on Friday, November 21 st . Learn more.Microsoft Defender for Office 365: Migration & Onboarding
This blog covers four key areas that are frequently missed, but they are essential for a secure and auditable deployment of Defender for Office 365. Before diving into the technical details, it is important to clarify a common misconception about Defender for Office 365 protections. Blocking Malicious File Downloads in SharePoint and OneDrive A common assumption during onboarding is that Microsoft Defender for Office 365 protections only apply to email. In reality, Safe Attachments also integrates with SharePoint Online, OneDrive for Business and Microsoft Teams. It scans files for malware even after they are uploaded or shared internally. However, this protection is only effective when the configuration explicitly prevents users from downloading files flagged as malicious. Without this setting, files detected as threats can still be downloaded locally. This creates a major risk particularly if the malware is detected post-delivery. In one investigation, I found that this setting had been left at its default, allowing users to download malicious files from SharePoint. This oversight created a significant exposure risk until it was corrected. This setting is part of the Safe Attachments for SPO/ODB policy and is critical in reducing internal exposure. Once enabled, this setting protects users in real time and acts as a powerful audit point. If someone disables this setting, whether intentionally or by accident, that action is recorded in Purview's Unified Audit Log under the DisallowInfectedFileDownloadDisabled operation. The video below offers a brief walkthrough on how to enable the setting, details the associated audit log events, and provides guidance on configuring alerts for any modifications: Regularly auditing for this event can help identify misconfiguration or potentially malicious administrative activity that could indicate insider threat behaviour. Including this check as part of your continuous security monitoring process is a smart, proactive move. Learn more at Step 2: (Recommended) Use SharePoint Online PowerShell to prevent users from downloading malicious files Once you have established protection against malicious files, the next step is ensuring your tenant is correctly set up to create and manage threat policies. Ensuring Organization Customization is Enabled A frustrating yet common hurdle during Defender for Office 365 onboarding is the inability to create threat policies such as anti-phishing or Safe Attachments policies. This confusion often stems from a basic configuration oversight: the tenant has not been enabled for organization customization. Without this step, the Microsoft 365 platform prevents the creation or editing of many critical security policies in Defender for Office 365. A few years prior with a new client being onboarded to Defender for Office 365, I encountered a situation where policy creation kept failing because this step wasn’t followed. It caused unnecessary delays and frustrated the security team until we identified the missing customization. The fix is simple. Run the Enable-OrganizationCustomization PowerShell cmdlet from Exchange Online. It is a one-time configuration task, but it is essential for policy management and overall service functionality. Including this step early in your deployment or migration plan prevents unnecessary delays and ensures the security team can fully leverage Defender for Office 365's capabilities from day one. This is particularly important for consultants who are brought in to assist after issues have already arisen. Getting ahead of this configuration means one less troubleshooting rabbit hole. With customization enabled, you can now take advantage of the preset security policies to quickly build a solid baseline. Using Preset Security Policies for a Strong Starting Point One of the best tools Microsoft has provided for onboarding is the Preset Security Policies feature. These come in two flavors: Standard and Strict. Figure 4 - Defender for Office 365 Preset security policies (Standard & Strict protection) They represent Microsoft’s recommended baseline configurations for anti-malware, anti-phishing, and spam protection. Learn more at Preset security policies in cloud organizations. For customers with limited security maturity or time to deeply understand the inner workings of Defender for Office 365, these presets are a game-changer. Figure 5 - Microsoft recommendation is to apply standard protection to all users In several cases, I have seen organizations with limited security teams benefit from activating these presets early. This approach gave them immediate protection while freeing up time to better understand and tune policies over time. For incident response, having a consistent and known-good baseline also helps reduce noise and false positives in the initial stages of deployment. Figure 6 - Apply strict Defender for Office 365 protection for priority users After setting foundational policies, controlling who has access to what within Defender for Office 365 is crucial to maintaining a secure environment. Implementing Unified RBAC for Least Privilege Access As more business units engage with Defender for Office 365 for everything from investigation to reporting, it is important to ensure each role has access only to what they need. Unified Role-Based Access Control (RBAC) in Defender for Office 365 makes this possible by allowing granular control over who can see and change what within the security portal. Figure 7 – Example least privilege role configuration for a Defender for Office 365 Incident Responder (image trimmed). This becomes critically valuable in larger or more complex organizations where responsibilities are split between security, compliance, IT, and operations teams. Figure 8 - Activating Microsoft Defender for Office 365 Workload in Defender XDR Roles. By using unified RBAC, you can avoid the dangerous and often default behavior of assigning Security Administrator rights to everyone involved. Instead, define roles based on function. For example, Tier 1 analysts might only need view and investigation access, while admins can manage policies. Figure 9 - Assigning a user to a Custom Microsoft Defender for Office 365 role, Entra Security Groups are also supported. This approach aligns with zero trust principles and makes it easier to audit who has access to sensitive areas. During onboarding, I recommend mapping stakeholders to the available roles and applying this model as early as possible. This helps establish accountability and improves your security posture before an incident occurs. Learn more at Map Defender for Office 365 permissions to the Microsoft Defender XDR Unified RBAC permissions Having set the right roles and permissions, it is vital to understand how these configurations contribute to a resilient and well-prepared security posture. Final Thoughts Successful onboarding to Microsoft Defender for Office 365 is not just about flipping switches. It is about making intentional configuration choices that support operational efficiency and long-term security goals. The points covered here are often missed in quick start guides but they are essential for building a solid foundation. Those who invest time in proper configuration are far better prepared when incidents arise. Migration is just the beginning. Set up Defender for Office 365 right to reduce risk and build real resilience. Please take two minutes to take this survey to let us know what you think of this blog (series), video, and community content. Questions or comments on this blog "Microsoft Defender for Office 365 Migration & Onboarding" for the author or other readers? Please log in and post your response below! _____________ This blog has been generously and expertly authored by Microsoft Security MVP, Purav Desai. with support of the Microsoft Defender for Office 365 product team. Lead M365 Incident Responder, Financial Services | Dual 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: (This post) 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 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
Help me understand why this email was quarantined?
I'm pretty familiar with Defender's Threat Policies. I've probably set them up on 40 tenants. I know the Hosted Content Filter Policy is backend for Anti Spam Inbound policy. I know that, confusingly, the AntiSpam Inbound Policies contain the actions for High Confidence/Normal Confidence Phishing - NOT the AntiPhishing policies (which seem more geared towards impersonation). What I DON'T know is why this was quarantined - and whether the anti-phish policy had anything to do with it. The Policy Type linked is the IB Anti Spam. This tenant is one of the few we have set at a BCL tolerance level of 7 - which shows me that 0 messages in the last 60 days would've been caught for this reason (which would include the email in question). So it was either the SCL or some 'anti phish' component of the anti-spam policy. I have none of the custom 'increase spam score' markers here. I was sure there was a 'evidence' tab within email entity, but i guess not - the only info I have about the detection (now released) is the following: This particular sender does not send reliably over 45 days, but also has been a business partner of this tenant for decades. So rather than the Tenant Allow/Block list which allows a max of 45 days, I want to add it to the offending policy. which SEEMS like it would be the inbound anti-spam - except that it also says it's phishing everywhere. I don't want to bypass both the phishing and spam policies unless I have to - but I don't really know why this got blocked. It's an external address that had sent an email days ago that got through without issue... This one has an attached pdf, but so do they all. Thoughts?Microsoft Defender EOP
We have been experiencing an issue since last week where we are unable to view the details of quarantined emails. Could you please confirm if this is related to a known backend service issue, or if there are any specific troubleshooting steps we should perform on our end? Any guidance or updates would be greatly appreciated.Auto-Remediation of Malicious Messages in Automated Investigation and Response (AIR) is GA
We are excited to announce the GA release of auto-remediation of malicious messages through automated investigation and response (AIR) expanding this powerful tool and deliver on full end to end automation of key SOC scenarios. AIR works to triage, investigate and remediate and respond to high-impact, high-volume security alerts providing tenant level analysis to increase customer protection and optimize SOC teams. With this enhancement, customers will be able to configure AIR to automatically execute remediations for messages within malicious entity clusters saving SOC teams time and further expediting remediation by removing the need to for SOC teams to approve these actions! To highlight the key user submission scenario, in addition to AIR completing triage, investigation, remediation identification, and end user feedback responses, customers may now configure AIR to take this a step even further to automatically execute on identified remediations. Auto-Remediation Action When AIR recognizes a malicious file or URL, it creates a cluster around the malicious file or URL grouping all messages that contain that file or URL into the respective cluster. The automated investigation then checks the location of the messages within the cluster and if it finds messages within user’s mailboxes, AIR will produce a remediation action. With the auto-remediation enhancement, if the customer has configured the cluster type to auto-remediate, this action will automatically be executed without the need for SecOps approval - removing identified threats at machine speed! Auto-remediated clusters showing in action center history with decided by stating automation: Configuration Auto-remediation will be controlled by a configuration within Settings > Email & Collaboration > MDO automation settings. Within the message clusters section, organizations may specify which types of message clusters they would like to be auto-remediated: Similar files: When the automated investigation recognizes a malicious file, it creates a cluster around the malicious file grouping all messages that contain that file into the cluster. Selecting this checkbox will opt the organization into auto-remediation for these malicious file clusters. Similar URLs: When the automated investigation recognizes a malicious URL, it creates a cluster around the malicious URL grouping all messages that contain the URL into the cluster. Selecting this checkbox will opt the organization into auto-remediation for these malicious URL clusters. The next configuration is for the remediation action, designating soft delete as soft delete is currently the only action supported through AIR. Auto-remediation of malicious entity clusters configuration found in settings>Email & collaboration>MDO automation settings: Note: Customers interested in auto-remediation must turn it on through the MDO automation settings page as it will not be on by default. Auto-Remediation Action Logging The Defender portal provides several ways for customers to review remediation actions to stay cognizant of the actions executed. These include within the investigation, action center, email entity as well as threat explorer and advanced hunting. Should customers disagree with the action executed, the ability to move the messages back to mailboxes is available as well based on configuration and timing. Auto-remediated messages showing in Threat Explorer Additional actions as Automated Remediation: automated: Auto-remediated messages showing in Advanced Hunting with ActionType as Automated Remediation and ActionTrigger as Automation: Learn More Register for the deep dive webinar on Microsoft Defender for Office 365 automated investigation and response (AIR) on June 25, 2025, at 8:00am PDT / 3:00pm UTC. Learn more about the feature enhancements, as well as how AIR can help optimize SOC teams and accelerate threat response. To learn more about the auto-remediation in AIR, please visit Automated remediation in AIR - Microsoft Defender for Office 365 | Microsoft Learn. To learn more about investigations in MDO, please visit the following pages: Automated investigation and response in Microsoft Defender for Office 365 - Office 365 | Microsoft Learn View the results of an automated investigation in Microsoft 365 - Office 365 | Microsoft Learn How automated investigation and response works in Microsoft Defender for Office 365 - Office 365 | Microsoft Learn Automatic user notifications for user reported phishing results in AIR - Microsoft Defender for Office 365 | Microsoft Learnupgraded from P1 to P2... how do I configure this?
Upgraded to Defender 365 P2 from P1, based on the automated responses. Kinda figured we'd be able to tweak these, but I guess not? Anyway, I'm a little bit confused about how to set this up maximally. Realized yesterday we had a 'User click a malicious link" investigation that was pending - but no one knew. When I click 'Email Notification' in the 'Incidents' window, it brings me to the XDR settings menu, with options for setting emails to notify of Alerts, Incidents and Threat Analytics. Except we don't have XDR? So I can't tell if these are even valid? The documentation on the AIR component is really hard to decipher - wondering if anyone has much experience with this, and knows how to configure it optimally? As in, how do I notify someone of a Critical Investigation, or something needing approval for remediation? Can I configure certain things to not require approval? Like... removing a reported phishing email from everyone's inbox?
