Microsoft 365 is the identity and collaboration backbone for many organizations. One set of credentials often unlocks email, files, chat, and dozens of connected apps, which means a single compromised account can give an attacker a lot of reach for very little effort.

A few reasons attackers favor Microsoft 365 specifically:

• It's everywhere. A huge share of small and mid-sized organizations run on Microsoft 365, so attackers can build repeatable playbooks that work across many targets.
• Native alerting has gaps. Microsoft's built-in tools generate a lot of log data, but flagging what's actually suspicious, in real time, without a security team watching it, is a different problem.
• One login opens many doors. A single compromised identity can touch email, files, calendars, Teams messages, and any third-party app a user has approved.

Business email compromise (BEC) via mailbox rules

A phished credential gets an attacker into a mailbox. Instead of sending obvious spam, they quietly create a forwarding or deletion rule so they can watch invoices and wire transfer conversations without the account owner noticing. This is one of the more common ways BEC escalates into real financial loss.

Consent phishing and malicious OAuth apps

Rather than stealing a password, an attacker tricks a user into approving a third-party app's permission request. Once granted, that app can read mail, access files, or maintain access even after a password reset, since no password was ever involved.

Session and token theft (Adversary-in-the-Middle)

Attackers increasingly skip the password step entirely by stealing an active session token, often through a phishing proxy that sits between the user and the real login page. With a valid session, MFA has already been satisfied, and the attacker can act as the user directly.

Lateral movement after initial compromise

Once inside, attackers rarely stop at one account. They test what else that identity can reach, look for ways to escalate privileges, and often register new access methods, like an OAuth app or a new device, to make sure they can get back in even if the original entry point is closed.

Each of these threats points to a specific gap a Microsoft 365 ITDR tool needs to close. Here's what that means in practice when you're evaluating one.

Continuous monitoring of Microsoft 365 identity activity

Microsoft 365 sign-in and directory activity contains most of the evidence of an identity attack: who signed in, from where, what changed, and what was created. The challenge is volume. A single business can generate thousands of events a day, and the signs of an actual attack are usually a small handful buried inside them. A Microsoft 365 ITDR tool should continuously ingest this data and correlate it against known attack patterns, not just store it for someone to search through after the fact.

Real-time detection of suspicious identity activity

Look for detection that covers the specific ways attackers operate inside Microsoft 365, including impossible travel and session anomalies, suspicious or hidden inbox rules, unusual OAuth app registrations or consent grants, and privilege or admin role changes that don't match normal behavior. Real-time matters here. An alert that arrives after the damage is done is a report, not a defense.

Session termination and automatic containment

Detection alone doesn't stop an attack in progress. The strongest Microsoft 365 ITDR tools can automatically remediate identity threats—such as disabling compromised accounts or blocking unwanted logins—once an attack is confirmed, cutting off access before an attacker can do more damage, rather than waiting for a person to see the alert and act on it.

Coverage built for Microsoft 365 specifically

Generic identity monitoring, built to cover many platforms at once, often misses the details that are unique to Microsoft 365, like how BEC typically escalates through malicious inbox and forwarding rules, or how consent phishing abuses Microsoft's OAuth app permission model.

Identity-only vendors like Semperis and Silverfort build deep platforms aimed at organizations with a dedicated identity security team, and for that audience, the depth is genuinely useful. These tools assume someone in-house is tuning detection rules, triaging alerts, and running the platform day to day.

Most growing businesses, and the MSPs supporting them, don't have that team in place. For them, a self-managed identity platform can mean more alerts to sort through and more responsibility landing on IT staff who are already covering everything else.

Managed ITDR approaches close that gap by pairing detection with a team that reviews activity around the clock, filters out the noise, and takes action when something's confirmed real. Neither model is universally "better." The right choice depends on whether your business has the in-house capacity to run a specialist tool, or needs that capacity built in.

• Continuously monitors and correlates Microsoft 365 identity activity, not just basic sign-in alerts
• Detects identity-focused behaviors specific to Microsoft 365, including malicious inbox and forwarding rules and rogue or malicious OAuth apps
• Can automatically remediate identity threats—such as disabling compromised accounts or blocking unwanted logins—not just send alerts
• Was built with Microsoft 365 identity and email risks as a core focus, not treated as just another generic integration
• Matches the operational reality of your team: in-house identity expertise versus a managed, 24/7 model
• Fits your organization's size; enterprise-built platforms don't always translate well to smaller environments, and vice versa

Enterprise identity platforms are generally built assuming a security operations team already exists to run them. Most small and mid-sized organizations, and the MSPs managing security across many clients, don't have that team.

Whether you build that through an in-house process, a managed vendor, or some mix of both, the fundamentals stay the same: watch Microsoft 365 identity activity closely, catch suspicious behavior early, and be able to cut off access fast once something's confirmed. Huntress Managed ITDR is one option built around exactly that model, a fully managed, 24/7 service that protects Microsoft 365 and Google Workspace identities and email environments, so organizations and MSPs can get enterprise-grade identity defense without standing up a security operations team from scratch.