Inbox Takeover Threat: What Every Business Needs to Know

The Reality of Inside Phishing Jobs

You’ve heard it a hundred times, “Watch out for phishing emails.” And while phishing is still a threat, the real inbox takeover threat is gaining momentum in 2025.

Hackers no longer need to trick you into clicking a malicious link. Sometimes, they are already inside your inbox, silently forwarding emails, creating filters, and waiting for the right moment to strike.

This growing danger, often called business email compromise (BEC), is one of the most damaging cyber threats businesses face today.

How an Inbox Takeover Threat Works

At first glance, email threats seem external. Most people think of suspicious links, attachments, or obvious scams. But once an attacker gets login credentials (often from a past breach or weak password reuse), they can log in just like a regular user. No alarms, no flashy red flags, and often, no one notices… for weeks.

Once inside, they:

• Set up auto-forwarding rules to steal sensitive information silently
• Monitor communication to learn how your business operates
• Pose as you or your staff in internal emails
• Redirect invoices and payments without raising suspicion

No phishing link. No malware. Just silent access.

Consequently, these threats are harder to detect and even harder to prevent if you’re not actively monitoring for them.

The Real Cost of an Inbox Takeover Threat

Unlike ransomware attacks, which are loud and disruptive, inbox takeovers are silent. There are no flashing alerts, no locked files. That quiet nature is exactly what makes them so dangerous.

If left undetected, these attacks can result in:

• Misrouted payments and wire fraud
• Leaked client or financial data
• Legal liabilities and compliance violations
• Lost trust and costly downtime

And this isn’t just theoretical. For example, a recent Forbes article revealed that over 16 billion passwords were exposed in a single silent breach – a staggering reminder of how dangerous undetected access can be. The longer attackers go unnoticed, the more damage they can do, without ever needing to send a phishing email.

It’s not about panic. It’s about preparedness. And knowing what to look for is the first step.

One of the Easiest Ways In: Forwarding Rules

One of the most common and overlooked tactics involves email forwarding rules.

Specifically, cybercriminals create rules that automatically forward any emails containing keywords like:

• “invoice”
• “wire transfer”
• “login credentials”

These emails are quietly sent to an external address. Typically, no one notices unless they are actively monitoring inbox settings.

Pro tip: Review mailbox rules and forwarding settings at least once a month. Even this small step can prevent a silent breach from causing serious damage.

What Real Email Security Looks Like in 2025

If your business relies only on spam filters and phishing training, you are only partially protected. Therefore, preventing inbox takeover threats requires a more proactive and layered approach.

Here are the essential steps to take:

1. Enforce Multi-Factor Authentication (MFA)

It’s not optional anymore. Even if a password gets leaked, MFA blocks most unauthorized access attempts.

2. Turn On Sign-In Location Alerts

Many email platforms (like Microsoft 365 and Google Workspace) offer alerts for sign-ins from new devices or suspicious locations. Enable them.

3. Monitor Audit Logs

Regularly review login history and activity to detect unusual access patterns. This allows your team to identify threats early.

4. Review Email Rules + Delegated Access

Look for unknown forwarding rules or unexpected shared access. These often signal compromise before other symptoms appear.

5. Educate Employees on More Than Just Phishing

Go beyond phishing awareness. Instead, teach your team how to recognize signs of unauthorized account access, even if no phishing attempt was involved.

It’s Not About More Tools. It’s About Seeing What Others Miss.

The real danger of unauthorized email access? Most businesses don’t even know it’s happening.

Meanwhile, flashy cybersecurity tools get all the attention. What you truly need, however, is better visibility into your email environment and a trusted IT partner who knows what to look for.

That’s where a proactive IT partner like Go2IT Group makes all the difference. We don’t just react to obvious threats. We help businesses uncover silent risks hiding in inbox settings, access controls, and overlooked rule configurations. In addition to responding to incidents, we proactively work to stop threats before they start.

Ready to find out what’s hiding in your inbox settings? Contact Go2IT Group today for a quick, no-pressure email security review.