How to Tell If Business Accounts Are Compromised (And What to Do About It)

For many small to medium-sized business owners, knowing how to tell if business accounts are compromised isn’t always straightforward. Maybe a customer mentions receiving a strange email from your address, or your files seem to have been accessed at odd hours. It’s easy to assume it’s just a glitch. But what if it’s not? What if someone unauthorized has access to your systems?

Unfortunately, you might not know until the damage is already done. Attackers today are stealthy and strategic—they may quietly monitor your communications, siphon data, or reroute emails without leaving obvious signs. For companies without a full-time IT team or with only basic in-house expertise, detecting and responding to these breaches can be overwhelming.

In this article, we’ll walk you through how to recognize signs of a compromised business account, what to do next, and how to reduce future risks. Whether you're actively investigating an issue or trying to stay ahead, this guide is a must-read for business leaders and owners.

A business owner reviews account activity for signs of unauthorized access—a crucial step in identifying if business accounts are compromised.

Why It’s Hard to Know If Your Business Accounts Are Compromised

When attackers gain access to a business account—especially platforms like Microsoft 365—they often act quietly. Instead of causing chaos, they may:

• Monitor communications for valuable information

• Forward emails to external addresses without your knowledge

• Send spam or phishing emails from your account

• Download sensitive business data

• Create hidden access rules to maintain control

This low-key approach is what makes knowing how to tell if business accounts are compromised so difficult.

Signs Your Business Account Might Be Compromised

Here are some subtle and not-so-subtle indicators that your business accounts might be at risk:

Strange Login Activity You Can't Explain

• Logins from unfamiliar countries or devices

• Unusual sign-in times, especially overnight or weekends

• Account lockouts or multiple failed login attempts

Suspicious Email Behavior or Missing Messages

• Reports of strange emails sent from your account

• Emails in your “Sent” folder you didn’t write

• Missing or moved emails

• Forwarding rules you didn’t create

Unexpected Changes to Account Settings

• Passwords reset or recovery options changed

• New users or admins appearing in Microsoft 365 or Entra ID

• Modified permissions or newly granted third-party app access

What to Do If You Suspect Your Business Accounts Are Compromised

If you're beginning to suspect a compromise in your business account, it’s essential to act quickly:

Step 1: Reset All Relevant Passwords

Start with email and administrator accounts. Make sure passwords are long, unique, and not reused across other systems.

Step 2: Review Login and Activity Logs

In Microsoft 365, use the audit log search or sign-in reports to check for unusual activity. Keep an eye out for:

• Unknown IP addresses or devices

• Times outside your normal working hours

• Changes in user behavior

Step 3: Inspect Email Settings and Permissions

Check for:

• Auto-forwarding rules to external addresses

• New inbox rules or filters

• Delegated access permissions

Step 4: Enable or Enforce Multi-Factor Authentication (MFA)

If you haven’t already, set up MFA on every account—especially admin roles. This adds a strong layer of security even if a password gets exposed.

Step 5: Run Malware and Security Scans

Attackers may install persistent access points or hidden backdoors. Use endpoint protection tools to scan all systems, and review integrated cloud applications for anything suspicious.

Step 6: Bring in Experts to Validate and Clean Up

It’s hard to know the full extent of a compromise without professional help. RND Tech specializes in Microsoft 365, Azure AD, and cybersecurity hardening. We can:

• Confirm whether a breach has occurred

• Investigate how it happened

• Help mitigate risks and secure your environment

• Offer guidance tailored to your business’s technical level and needs

How to Stay Ahead of Business Account Compromises

Once you’ve responded to a threat, the next step is making sure it doesn’t happen again. Here’s what you can do proactively:

• Regularly review sign-in logs and audit trails

• Set up automated alerts for suspicious activity

• Train employees on how to identify phishing or scams

• Apply the principle of least privilege—only give access as needed

• Schedule periodic cybersecurity assessments

You don’t need to become a security expert yourself—but you do need someone who is in your corner.

Final Thoughts

Knowing how to tell if business accounts are compromised is an essential part of running a modern business. Whether you’re a tech-savvy entrepreneur or someone who just wants their systems to “work,” spotting the signs early can save you time, money, and reputation.

Don't ignore the signs. And don't go it alone. If you think something’s off—or just want peace of mind—consider bringing in professionals like RND Tech to assess your environment and guide your next steps.

Stay secure, stay informed, and stay in control.