Microsoft 365 inbox rule monitoring

Attackers hide inside
your mailboxes.
IRM finds them.

The most dangerous inbox rule attacks don't forward email externally — they hide it. IRM monitors every rule change across every mailbox and raises an alert the moment something suspicious appears.


How it works

From suspicious rule to alert — in minutes.

IRM connects directly to Microsoft 365 using certificate-based authentication. No passwords. No agents. No complex setup.

01

Connect your tenant

Sign in as Global Admin once. IRM creates the app registration, uploads the certificate, and configures Exchange access automatically — under 5 minutes per tenant.

One-time setup per tenant
02

Continuous monitoring

IRM scans every mailbox across all configured tenants on a schedule you control. Every rule is compared to the previous snapshot — detecting any change the moment it happens.

Configurable scan interval
03

Alert raised

Suspicious changes raise an alert on your dashboard and by email. Each alert includes the affected mailbox, what changed, risk level, and recommended action — no log-digging required.

Dashboard + email notification

The threat

The most dangerous inbox rule attacks
don't forward email externally. They hide it.

Sophisticated attackers use hidden folder rules to intercept conversations without ever touching the outbox. Here's how it happens.

1
Sarah Chen receives a phishing email

Sarah is the Accounts Payable manager at Acme Corporation. She receives what looks like a DocuSign request from a vendor. She clicks the link, enters her Microsoft 365 credentials.

The attacker now has full access to her mailbox — from a server in Eastern Europe.
2
A hidden folder rule is created

The attacker creates one rule: emails from Supplier B — Vantage's primary vendor — move silently to a folder called "Archive2." Marked as read. Sarah never sees them.

Rule name: "Archive2" · Action: Move to folder + Mark as read · From: supplier.example.com
3
The conversation is hijacked

The attacker monitors Archive2 and replies as Sarah — impersonating her to Supplier B. They explain that Acme Corporation has switched banks and provide new wire transfer details.

Supplier B updates their records. They have no reason to doubt — the email came from Sarah's account.
4
The wire transfer is sent

Supplier B processes the next invoice. $94,000 is wired to the attacker's account. Acme Corporation discovers the fraud six weeks later when Supplier B calls about the overdue payment.

The attacker was inside the mailbox for 41 days. Sarah never knew the conversation was happening.
With IRM: alert raised at Step 2

The moment the Archive2 rule was created, IRM flagged it — full rule details, the affected mailbox, and risk level. IT investigates. The rule is removed. Sarah's password is reset. No money moves.

Alert raised within minutes of rule creation. Breach contained before any financial damage.
IRM Alert — triggered at Step 2 What your dashboard shows
● HIGH — Rule Created
sarah.chen@example.com
Rule: "Archive2"
Action: Move to folder "Archive2" · Mark as read
From filter: supplier.example.com
Alert raised · 2:14 AM
● MED — Rule Modified
asmith@example.com
Rule: "Payment Received"
ForwardTo changed: none → external address
● LOW — Rule Modified
mjones@example.com
Rule: "Newsletter Archive"
Priority changed: 5 → 8
What IRM monitors
Move to folder rules — including hidden folders
External forwarding and redirects
Delete message rules
Mark as read rules
Stop processing rules
Rule deletions
Any combination of the above

Rule Analyzer

Your tenant has inbox rules
you've never seen. Now you can.

Before you can monitor for changes — you need to know what's already there. Rule Analyzer gives you a complete picture of every inbox rule across your entire Microsoft 365 tenant. Most organizations discover rules they never knew existed.

Expose prior breaches

Attackers plant rules and walk away. Rule Analyzer finds rules that have been sitting in mailboxes for months — hidden folder rules, silent forwards. Most clients find something on day one.

Every rule, every mailbox

See all inbox rules across your entire tenant organized by user — not one mailbox at a time. Filter by risk, search by name, group by mailbox. Export to CSV for compliance reporting.

Flag View — suspicious rules only

Switch to Flag View to see only rules that warrant review — external forwards, hidden folder rules, delete-on-arrival rules. Cut through the noise in seconds.

Mark reviewed, track progress

As you work through rules with your client, mark each one reviewed. Build a documented audit trail of your inbox rule environment for compliance and security reporting.


Features

Built for the people responsible
for keeping email secure.

Whether you're an in-house IT admin or managing dozens of client tenants, IRM gives you the visibility that Microsoft 365 doesn't provide out of the box.

Real-time rule detection

Every mailbox, every scan. IRM compares rule snapshots across all tenants and flags any created, modified, or deleted rule — with full before/after details in every alert.

Configurable scan interval

Rule Analyzer

A live view of every inbox rule across every mailbox. Search, filter by risk, group by mailbox, and expand any rule to see exactly what it does. Ideal for baseline audits of new clients.

Audit all rules at a glance

Auth Monitor

Detect new device sign-ins, failed MFA attempts, foreign logins, and brute force patterns across all monitored tenants — sourced from Microsoft 365 audit logs and may be delayed.

Sign-in anomaly detection

Rich alert emails

Every alert includes the affected mailbox, the rule name, what changed, risk level, and recommended action. Before/after comparison included. No log-digging required.

Before/after comparison

Multi-tenant dashboard

Monitor all tenants from one interface. Each client gets independent scan schedules, alert recipients, and rule history. Scales from single-org IT to a 25-tenant MSP operation.

Up to 25 tenants

Zero credentials stored

Certificate-based Azure AD authentication only. No passwords, no OAuth tokens on disk. IRM reads inbox rule configurations and mailbox lists only — it never accesses email content, attachments, calendar data, or any other mailbox data. It cannot modify rules or settings.

Cert-based auth only


Multi-tenant management

All your tenants.
One dashboard.

Add a new tenant in under 5 minutes. Monitor indefinitely. Each organization gets its own scan schedule, alert configuration, and rule history.

Tenants
Mailboxes
Last Scan
Status
A
Acme Corporation
acme.example.com
67
2 min ago
● No changes
B
Globex Corp
globex.example.com
24
4 min ago
● 1 alert
C
Initech
initech.example.com
41
6 min ago
● No changes

Pricing

Simple annual pricing.
No per-seat surprises.

All plans include inbox rule monitoring, Rule Analyzer, real-time email alerts with full rule details, daily digest reports, multi-tenant dashboard, certificate-based authentication, CSV export, and software updates. Contact us for pricing tailored to your organization.

Everything included in every plan
Inbox rule monitoring
Rule Analyzer
Software updates included
Real-time email alerts
Daily digest reports
Multi-tenant dashboard
Certificate-based auth
CSV & PDF export
Email support
Starter
For small business IT teams
25mailboxes
1tenant
Request Access
Professional
For larger IT teams and growing MSPs
250mailboxes
10tenants
Request Access
Enterprise
For enterprise IT and large MSPs
500mailboxes
25tenants
Request Access
Pricing tailored to your organization. Contact us to discuss your requirements.

Start monitoring in under 10 minutes.

No cloud infrastructure required. Installs on any Windows desktop or server. Free trial available.