How to Use Microsoft 365 Conditional Access to Block Logins from High-Risk Countries

It usually starts with something small, such as a login that doesn’t make sense. Same username, but a completely different country. That’s how you discover your company’s been breached. In today’s world, it doesn’t take much. Most breaches don’t happen because someone breaks in, they happen because someone manages to sign in.

The FBI’s 2024 Internet Crime Report counted over $16.6 billion in losses, from online crimes, up more than 30% from the year before. Microsoft followed with its own 2025 report, noting that identity attacks jumped another 32% in the first half of the year. 

For any business running on Microsoft 365, that reality hits close to home. The platform provides strong built-in security, but Conditional Access adds a crucial layer of common sense. It determines who can sign in, from where, and under what conditions. When configured properly, Conditional Access quietly blocks those distant, suspicious logins before anyone even knows they happened.

Why Blocking High-Risk Countries Is Worth the Effort

Credentials are the new currency. Verizon’s 2025 Data Breach Report found that 22% of all breaches start with stolen passwords, and 88% of web attacks rely on them. Once an attacker lands inside a Microsoft 365 account, they can move through MS Teams, OneDrive, and shared drives, often finding much more than expected.

That’s where location filtering comes in. By blocking sign-ins from high-risk regions, you reduce exposure to areas where cybercrime is most active, or where your business simply doesn’t operate. After all, if you run a construction firm in Tennessee, a midnight login from Eastern Europe probably isn’t one of your project managers.

Setting Up Conditional Access in Microsoft 365

Conditional Access lives inside Microsoft Entra ID (formerly Azure AD). Every time a user tries to sign in, Microsoft checks the attempt against your conditions such as location, device type, and risk level, and applies the rules you have defined.

Here’s how to build it out in a way that works for real life, not just policy manuals.

1. Know What “Normal” Looks Like

Start by mapping your geography. Where are your offices? Which countries do employees travel to? Are contractors or vendors signing in remotely? Getting those answers on paper first will save a lot of stress later.

A few quick questions can help you frame the discussion:

• Does anyone log in regularly from outside your region?
• Do integrations or automation tools connect through non-U.S. data centers?
• What would happen if all foreign logins were blocked tomorrow?

2. Create Locations and Rules

Go to Entra ID → Protection → Conditional Access → Named Locations, define which countries are allowed and which are not. Name them clearly, something like Blocked – High Risk or Trusted – Corporate IPs.

Then build the policy:

1. Select your user group (all or specific roles)
2. Choose the apps you want to protect, usually Office 365
3. Under Conditions → Locations, include All Locations and exclude the trusted ones
4. Under Access Controls, set it to Block Access
5. Keep the policy in Report-only mode for a few days before enforcing it

For teams focused on improving access control, this setup naturally supports smart cloud storage habits, that keep collaborations smooth and data safeguarded.

3. Add a Safety Net

Conditional Access can be powerful, but if every door locks at once, you need a way back in.

Keep one emergency administrator account exempt from all Conditional Access rules. This “break-glass” login ensures you can regain access if a policy ever locks you out. 

An emergency administrator account also lets you create an allow rule for trusted office networks or verified U.S. IPs, helping prevent service interruptions. Once that’s in place, tighten everything else: turn on multi-factor authentication (MFA) for all users, enforce device compliance for company machines, and disable old protocols like IMAP or POP that don’t respect Conditional Access or modern security checks.

4. Monitor and Adjust

Policies change over time. Travel patterns shift, vendors come and go, and attackers adapt. Conditional Access provides detailed sign-in logs in the Entra dashboard,  use them. Watch for failed logins from blocked regions or accounts that suddenly show unusual behavior.

If a legitimate user is flagged while traveling, create a short-term “Allowed – Travel” group. For a verified overseas contractor, adjust their policy to require MFA and device compliance rather than blocking access entirely.

Security isn’t static. The healthiest systems are the ones that keep learning.

5. Expect a Few Oddities

Conditional Access is highly effective, but be prepared for a few surprises:

• Mobile carriers sometimes route data through other countries.
• VPN users can appear offshore even when they’re not.
• Some SaaS platforms authenticate through global data centers.

The fix is usually testing first, enforcing later. Microsoft already processes 38 million identity-risk detections per day, so you’ll have plenty of telemetry to guide you.

Take Back Control of Your Sign-Ins

Blocking logins from high-risk regions won’t solve everything, but it closes one of the easiest paths into your environment. It reduces noise, keeps alerts meaningful, and adds clear accountability for who can access your network.

Pair it with MFA, device compliance policies, and regular reviews, and you’ve built a strong, practical security framework, something any small or midsized business can implement without complex infrastructure.

At Unbound Digital, we help businesses strengthen security without disrupting daily workflows. Our team designs and manages Microsoft 365 Conditional Access policies, handles migrations and email configurations, and ensures everything stays reliable and compliant.

Ready to block risky sign-ins while keeping trusted users connected? Contact us, and we’ll help you build a Conditional Access strategy tailored to your business.