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Microsoft 365 Security Audit Service: Uncover Hidden Threats in Your Business Tenant

Your business relies heavily on Microsoft 365. It serves as the digital headquarters for your team, housing your most critical emails, sensitive client data, internal chats, and financial records. Because it contains such valuable and confidential information, your Microsoft 365 environment is a massive target for cybercriminals.

Many business owners assume their network is secure simply because they use standard tools like antivirus software or basic spam filters. Unfortunately, the modern threat landscape has evolved far beyond these legacy defenses. Attackers no longer need to break through a firewall; they simply log in by stealing employee credentials or bypassing authentication protocols. Once inside, they operate quietly, studying your communication habits and waiting for the perfect moment to launch a devastating attack.

To truly secure your organization, you need profound visibility into what is happening inside your cloud environment. You must know if your configurations are correct, if your defenses are working, and most importantly, if an attacker has already bypassed your security.

This is exactly why we offer our comprehensive Microsoft 365 Security Audit Service. Designed to give you a clear, unvarnished look at your tenant’s security posture, our service helps you identify vulnerabilities before they become headline-making breaches. Whether you need a quick baseline checkup or a deep retrospective forensic analysis, our auditing solutions provide the clarity you need to protect your business.

Why Your Business Urgently Needs a Microsoft 365 Security Audit

The statistics surrounding cloud security breaches are alarming. Cybercriminals have industrialized their attack methods, using automation to target organizations of all sizes. Even small and medium-sized businesses with fewer than 1,000 employees have a massive 70% chance of facing at least one Business Email Compromise (BEC) attempt every single week.

The Silent Destruction of Account Compromises

Account compromises occur when an attacker successfully infiltrates a legitimate employee account. Instead of deploying noisy ransomware right away, they prefer to weaponize the trusted account to inflict financial or reputational harm.

Currently, 90% of breaches worldwide originate from phishing attacks. Once the attacker gains access, they frequently target your billing and finance departments. Our data shows that 29% of identity-based attacks result directly in wire fraud. Over the last decade, businesses have lost an astonishing $50 billion due to Business Email Compromise, making it the costliest cybercrime in the world.

When a hacker takes over a trusted employee account, they can send emails to your clients or vendors that appear 100% legitimate. If “Brad from Accounting” sends an urgent updated invoice with new wire transfer instructions, your clients are highly likely to pay it. The average cost per incident involving wire fraud is now a staggering $137,000. A Microsoft 365 security audit helps you spot the vulnerabilities that make these attacks possible.

Multi-Factor Authentication (MFA) Is No Longer a Silver Bullet

For years, the standard advice from IT professionals was simple: turn on Multi-Factor Authentication (MFA) and your accounts will be safe. While MFA remains a critical baseline security measure, it is no longer sufficient to stop determined attackers.

Cybercriminals have developed sophisticated methods to bypass these protections. We have observed a 146% increase in MFA-bypass phishing attacks recently. In fact, an estimated 75% of modern Business Email Compromise attacks successfully bypass MFA entirely.

Attackers achieve this through advanced tactics like session token theft, also known as session hijacking. They use “Attacker-in-the-Middle” phishing sites that not only steal the user’s password but also capture the authenticated session cookie generated after the user approves the MFA prompt. With this token, the attacker can paste it into their own browser and gain immediate, fully authenticated access to your Microsoft 365 account without ever triggering another MFA request.

Because standard security tools cannot distinguish between a legitimate user and an attacker holding a stolen token, these breaches go unnoticed. A thorough security audit is the only way to uncover the subtle behavioral anomalies that indicate a bypassed authentication.

Schedule your Free Microsoft 365 Security Audit

Services

Level 1: The Free Microsoft 365 Security Scan

We believe that every organization deserves to know their baseline security posture. That is why we offer a completely free, initial Microsoft 365 Security Scan for prospective clients. This essential checkup is designed to provide rapid insights into the overall health of your environment and highlight immediate, glaring vulnerabilities.

What the Free Security Scan Covers

Our free scan is a fast, non-intrusive evaluation of your Microsoft 365 tenant. It does not require installing complex software or enduring weeks of business disruption. We simply connect to your environment using secure, read-only administrative access to analyze your current configurations against industry best practices.

Identifying Critical Misconfigurations

Microsoft 365 is a powerful platform, but it is notoriously complex to configure correctly. Out of the box, the default security settings prioritize user convenience over strict security, leaving dangerous loopholes open.

Our free scan looks for common misconfigurations that attackers frequently exploit. We check your email authentication protocols, such as SPF, DKIM, and DMARC, to ensure unauthorized users cannot spoof your company domain. We also review your external sharing settings in SharePoint and OneDrive. If your users can freely share highly sensitive company documents via anonymous links to anyone on the internet, your data is at severe risk. We highlight these misconfigurations so you can tighten your policies immediately.

Spotting Missing MFA and Weak Policies

While we know MFA can be bypassed, failing to enforce it at all is like leaving your front door wide open. Our security scan instantly identifies any user accounts in your tenant that do not have Multi-Factor Authentication enabled and enforced. We frequently find that businesses have MFA turned on for regular employees but accidentally leave it disabled for critical service accounts, shared mailboxes, or legacy administrative accounts.

Furthermore, we review your conditional access policies. We check if you are blocking legacy authentication protocols (like POP3 or IMAP) which do not support modern MFA and are actively hunted by automated password-spraying bots.

Reviewing General Health and Recent Incidents

Finally, the free scan provides a high-level overview of your tenant’s general health. We look for simple, immediate red flags. Are there global administrator accounts that haven’t been used in months? Are there recent, highly suspicious login failures from foreign countries? We compile these findings into a clear, easy-to-understand health report, giving you a snapshot of your current security reality and a prioritized list of quick fixes.

Stopping the Threat: Post-Audit Remediation

If our Free Security Scan or our premium Autopsy reveals an active compromise or a lurking attacker, time becomes your most critical asset. You cannot afford to wait. We seamlessly transition from auditing to immediate incident response.

Our expert security team will intervene to severe the attacker’s access immediately. We force global password resets, revoke all active web session tokens to neutralize token theft, and delete any malicious inbox rules or rogue OAuth applications the attacker left behind. We ensure your environment is completely sanitized, closing the doors the hackers used to enter. Furthermore, we provide you with a comprehensive report detailing exactly what data was exposed, which is essential for your internal legal and compliance requirements.

Sentinel for Microsoft 365: Your Ongoing 24/7 Protection

A security audit, even an advanced Autopsy, is ultimately a point-in-time assessment. It tells you exactly how secure you are on the day the report is generated. However, the cyber threat landscape is continuous. An hour after you finish remediating a vulnerability, a new phishing campaign could successfully trick one of your employees, starting the breach cycle all over again.

To ensure your business remains secure long-term, you must move from reactive auditing to proactive, continuous defense. This is where our Sentinel for Microsoft 365 solution comes in.

Continuous Identity Threat Detection and Response (ITDR)

Sentinel for Microsoft 365 is a fully managed, turnkey security service designed to protect your tenant 24 hours a day, 7 days a week, 365 days a year. We take the exact same advanced analytical engine and behavioral baselining used in our Autopsy service and apply it to your live environment in real-time.

Sentinel provides true Identity Threat Detection and Response (ITDR). It does not just look for bad files; it continuously monitors user identities and authentication behaviors. When an attacker attempts to bypass MFA using a stolen session token, Sentinel detects the anomaly instantly.

Catching Attackers Before the Damage is Done

The goal of Sentinel for Microsoft 365 is speed. In the Autopsy example mentioned earlier, the attacker had two months to access data and send malicious emails. With Sentinel active, that timeline shrinks to minutes.

When a compromised account exhibits suspicious behavior—like suddenly downloading bulk files from SharePoint or creating an unusual email forwarding rule—Sentinel triggers an immediate response. Our 24/7 Security Operations Center (SOC) investigates the alert. If a threat is confirmed, we isolate the compromised account instantly. We lock the attacker out before they can access sensitive data, before they can cause reputational harm by sending phishing emails to your contacts, and before they can execute wire fraud.

Co-Managed Security for Ultimate Peace of Mind 

Managing Microsoft 365 security is a full-time job that requires deep, specialized expertise. Most internal IT teams are already stretched too thin handling daily helpdesk tickets, infrastructure upgrades, and strategic business projects. They simply do not have the time to hunt for advanced identity threats in the cloud manually. 

Sentinel for Microsoft 365 acts as a powerful extension of your existing team. We provide the elite, 24/7 security monitoring, the expert threat hunting, and the immediate incident response, freeing your staff to focus on driving your business forward. We deliver enterprise-grade cloud security without the massive overhead of hiring your own internal security operations center. 

Level 2: The Microsoft 365 Advanced Security Analysis (Premium Advanced Scan)

While the free Security Scan is excellent for identifying surface-level misconfigurations, it cannot tell you if an attacker has already bypassed your defenses and is currently hiding within your network. For businesses that require absolute certainty, or those that suspect they may have suffered a silent breach, we offer our premium, charged service: The Microsoft 365 Autopsy.

What is the Advanced Security Analysis Service?

The Advanced Security Analysis is a highly advanced, retrospective 6-month forensic analysis of your entire Microsoft 365 environment. It is the definitive way to surface forensic details of past account compromises and catch currently lurking attackers.

Unlike a simple configuration check, the Autopsy processes massive amounts of historical activity metadata. It requires no software installation and typically takes just 48 hours to complete once initiated. Importantly, the Autopsy focuses strictly on metadata—it does not process, read, or expose the actual contents of your private company emails, ensuring your internal privacy remains intact.

Deep Dive into Entra, Exchange, OneDrive, and SharePoint

To conduct the Autopsy, our advanced analytical engine gathers six months of activity logs from across your tenant. We pull detailed telemetry from Microsoft Entra ID (formerly Azure AD), Exchange Online, OneDrive, SharePoint, and Microsoft Teams.

By analyzing this vast dataset, we build a computed behavioral baseline for every single employee in your organization. We learn what normal looks like: where they usually log in from, what devices they use, what files they typically access, and who they normally email.

Hunting for Lurking Attackers and Malicious Persistence

Once we establish the baseline, we hunt for the sophisticated attacker patterns that bypass standard security tools. We are specifically looking for attackers who have already infiltrated your employee accounts and are waiting to strike.

Often, an attacker will compromise an account and then create “persistence mechanisms” to ensure they can get back in even if you force a password reset. The Advanced Security Analysis thoroughly hunts for these hidden traps. We look for rogue OAuth applications—malicious third-party apps that users accidentally granted access to, which silently harvest data in the background. We also hunt for hidden inbox rules in Exchange. Attackers create these rules to automatically delete or hide incoming replies to their fraudulent wire transfer requests, keeping the legitimate account owner completely blind to the ongoing scam.

Detecting Sophisticated Attacker Patterns

A standard security tool might flag a login from a new country, but it often misses the nuanced behavior of a professional cybercriminal. The Advanced Security Analysis differentiates between low-level, noisy attackers and highly sophisticated threat actors.

We analyze classic signals like impossible travel (logging in from New York and London within ten minutes) and the use of anonymous routing VPNs. But we go much further. We look at post-compromise behavior. If an account suddenly accesses 50 sensitive financial records in SharePoint that the user has never touched before, our engine flags this as a critical anomaly, even if the login appeared to originate from a normal location.

Real-World Advanced Security Analysis Findings

The results of an Advanced Security Analysis can be shocking. In past analyses, we have uncovered attackers who remained completely undetected inside a client’s network for over two months.

In one such scenario, an attacker bypassed MFA and gained access to a Billing Administrator’s account. Over the course of 70 days, the attacker quietly accessed numerous financial records, studied invoicing patterns, and eventually sent highly convincing, malicious emails to the company’s clients requesting updated payment routing. The existing security software never triggered an alert because the attacker was using a legitimate, authenticated session. The Advanced Security Analysis revealed the exact timeline of the breach, exactly which sensitive files were accessed, and the precise malicious emails that were sent, allowing the company to finally calculate their exposure and stop the bleeding.

How to Evaluate Your Current M365 Security

If you currently rely on another IT provider or standard out-of-the-box Microsoft tools, you need to ask yourself a few critical questions to determine if you are truly protected against modern account compromises.

  • Does your current solution detect attacks before damage is done? Can it spot an intruder before financial risk is created, before reputational harm is caused to your brand, or before sensitive intellectual property is accessed?
  • Does your team respond in just a few minutes? Attackers move incredibly quickly. They often begin exfiltrating data or sending malicious emails within minutes of gaining initial access. If your IT team only reviews security logs once a week, it is far too late.
  • Does your security provide deep forensic visibility? If an account is breached, can your provider show you exactly what the attacker did? Can they produce a report showing precisely which emails were read and which SharePoint files were downloaded? If not, you will never truly know the scope of a breach.
  • Are phishing emails removed post-detection? If a malicious email makes it past the spam filter and lands in an employee’s inbox, does your security solution automatically yank it back out before other users can click it? If not, a small, isolated compromise can rapidly spread into a company-wide disaster.

If you cannot confidently answer “yes” to these questions, your Microsoft 365 environment is vulnerable.

Schedule Your Free Microsoft 365 Security Audit Today

Do not wait for a devastating Business Email Compromise attack or a massive data theft incident to force your hand. The financial and reputational costs are simply too high. Take proactive control of your cloud environment today.

Start with our Free Microsoft 365 Security Scan to get a rapid baseline assessment of your tenant’s health, identify missing MFA configurations, and uncover risky settings. If you suspect deeper issues, authorize a Premium Advanced Security Analysis to hunt for lurking attackers and historical breaches across your entire environment.

Finally, secure your business for the future by deploying Sentinel for Microsoft 365, ensuring you have elite, 24/7 human-led protection watching over your most critical data.

Contact us immediately to schedule your free audit and take the first step toward true cloud security.

Start with our Free Microsoft 365 Security Scan to get a rapid baseline assessment of your tenant’s health, identify missing MFA configurations, and uncover risky settings. If you suspect deeper issues, authorize a Premium Autopsy to hunt for lurking attackers and historical breaches across your entire environment.

Finally, secure your business for the future by deploying Sentinel for Microsoft 365, ensuring you have elite, 24/7 human-led protection watching over your most critical data.

Contact us immediately to schedule your free audit and take the first step toward true cloud security.

Microsoft 365 Security Audits and Compromises

To help you better understand the importance of auditing and securing your cloud environment, we have compiled detailed answers to the most frequently asked questions about Microsoft 365 security.

A Microsoft 365 Security Audit is a comprehensive evaluation of your cloud environment’s security posture. It involves reviewing your administrative configurations, authentication protocols, external sharing settings, and user behaviors to identify vulnerabilities. Audits range from quick baseline configuration scans to deep, retrospective forensic analyses designed to find hidden attackers.

The Free Security Scan is a quick, point-in-time checkup that looks for surface-level misconfigurations, missing Multi-Factor Authentication (MFA), and basic tenant health. The Advanced Security Analysis is a premium, advanced service that performs a deep, 6-month retrospective forensic analysis of your metadata to actively hunt for sophisticated attackers, historical compromises, and hidden persistence mechanisms like rogue applications.

No. The Autopsy service is strictly focused on metadata, not content. It analyzes the forensic logs of your activity—such as login locations, timestamps, file access records, and email routing rules—to identify malicious patterns. It does not process, read, or export the actual text or attachments within your private emails.

Yes, absolutely. Modern cyber attacks frequently bypass traditional email security and spam filters. Attackers often compromise a trusted third-party vendor and send phishing links from a legitimate, trusted domain. Once an attacker bypasses the spam filter and steals a session token, they operate inside your environment where the spam filter cannot see them. An audit checks for these internal compromises.

Once initiated, the Advanced Security Analysis typically takes just 48 hours to complete. Because it processes historical logs and metadata via the cloud, there is no software to install on your local machines and no disruption to your employees’ daily work. You receive a comprehensive forensic report upon completion.

No, you do not need to hand over your administrator password. To initiate a scan or an Autopsy, we provide a secure, one-click authorization link. A global administrator in your organization simply clicks the link to securely grant our analytical engine the specific, read-only permissions required to analyze the logs.

Business Email Compromise (BEC) is a type of cybercrime where an attacker hacks into a legitimate corporate email account and uses it to conduct fraud. They typically monitor the account to understand billing cycles, then impersonate an employee to trick clients, vendors, or the finance department into wiring money to the attacker’s bank account. It is incredibly dangerous because the fraudulent requests come from a trusted, internal email address.

Hackers bypass MFA primarily through a technique called session token theft or session hijacking. When an employee logs in and approves an MFA prompt, the browser creates a secure “session cookie” so the user doesn’t have to keep authenticating. Attackers use advanced phishing websites to intercept and steal this active session cookie, allowing them to bypass the login screen entirely.

Sentinel for Microsoft 365 is our fully managed, 24/7/365 security monitoring service. It provides continuous Identity Threat Detection and Response (ITDR). While an audit looks at the past, Sentinel monitors your live environment in real-time, detecting and instantly blocking compromised accounts, impossible travel logins, and malicious file access before damage occurs.

Common signs of an active compromise include employees complaining about missing emails, the sudden appearance of unexpected inbox forwarding rules, clients receiving strange invoices from your domain, or unusual login alerts from foreign countries. However, sophisticated attackers hide their tracks well. The only definitive way to know if your tenant is compromised is to perform a deep forensic analysis like our Advanced Security Analysis service.