Ottawa businesses run on Microsoft 365. Default settings, however, leave the door wide open for credential theft, phishing, and ransomware. Microsoft blocked over 70 billion credential-based attacks in 2025 alone – most targeting poorly hardened tenants. This comprehensive 2026 checklist shows Ottawa SMEs exactly how to lock down Microsoft 365 without slowing down daily work. Bedrock IT delivers this exact hardening as part of our Ottawa IT support packages.
Why Ottawa Businesses Need M365 Hardening Now
Microsoft 365 is the number-one attack surface for Canadian companies. Weak Conditional Access, disabled MFA, and legacy authentication still account for the majority of successful breaches. A properly hardened tenant reduces successful phishing by up to 99.9 percent and meets PIPEDA and CASL requirements without extra paperwork. Whether you run a law firm, retail chain, or construction company in Ottawa, the same core controls apply.
Step-by-Step Microsoft 365 Hardening Checklist
- Enable Security Defaults or Baseline Conditional Access
Turn on Microsoft’s Security Defaults (or create equivalent policies) to block legacy authentication and require MFA for all admins immediately. - Enforce MFA for All Users
Use Conditional Access to require MFA on every sign-in from untrusted locations or devices. Bedrock IT configures phishing-resistant methods (FIDO2 keys, Microsoft Authenticator push) as standard Ottawa IT support. - Block High-Risk Sign-Ins
Create policies that block logins from anonymous IPs, impossible travel, or known attack countries unless MFA is satisfied – see the official risk-based Conditional Access guide. - Apply Preset Security Policies
Enable Standard or Strict preset policies in Microsoft Defender for Office 365 – full documentation here. These pre-built rules include Safe Links, Safe Attachments, and anti-impersonation protection. - Turn On Safe Links and Safe Attachments for Everyone
Ensure both features apply to internal and external mail – Safe Links and Safe Attachments documentation. Ottawa businesses using our managed IT support have these enabled by default. - Configure Anti-Phishing Protection
Raise impersonation protection thresholds and add key executives and common vendor domains to the protected list. - Enable Microsoft Defender for Endpoint
Deploy Defender for Endpoint to all Windows, macOS, iOS, and Android devices. This gives real-time visibility and automated response. - Set Up Device Compliance with Intune
Require devices to be compliant (encrypted, up-to-date, no jailbreak/root) before granting access to email and OneDrive. - Implement Data Loss Prevention (DLP)
Create policies that block credit-card numbers, health card numbers, and SINs from leaving via email or Teams – full DLP guide. - Turn On Audit Logging and Alerts
Route all audit logs to Microsoft Sentinel or your SIEM for 365-day retention and instant alerts on suspicious activity. - Restrict App Permissions and Consent
Block user consent to third-party apps and require admin approval for OAuth permissions. - Schedule Regular Reviews
Bedrock IT performs quarterly hardening reviews as part of every Ottawa IT support agreement.
Quick Wins You Can Do Today
- Sign in to the Microsoft 365 Defender portal and enable Security Defaults (takes 60 seconds)
- Turn on MFA for all global admins
- Enable Safe Links and Safe Attachments for the entire organization
- Block legacy authentication (responsible for 99 percent of password-spray attacks)
Take the Next Step with Bedrock IT
Ottawa IT support doesn’t have to be complicated. Bedrock IT hardens Microsoft 365 tenants for hundreds of local businesses every year using the exact checklist above. We handle licensing, configuration, user training, and ongoing monitoring so you stay secure without lifting a finger.
Get your free Microsoft 365 security scorecard and hardening roadmap today.
Call us at (613) 702-5505
Email [email protected]
Book your no-cost review https://ottawa-it-services.ca/microsoft-365/
Glossary of Technical Terms
| Conditional Access | Microsoft policy engine that evaluates sign-in risk and enforces controls |
| Multi-Factor Authentication (MFA) | Requires two or more verification factors to prove identity |
| Safe Links | Real-time URL scanning and detonation in Microsoft Defender |
| Safe Attachments | Cloud sandbox that detonates email attachments before delivery |
| Data Loss Prevention (DLP) | Policies that prevent sensitive data from leaving the organization |
| Microsoft Sentinel | Cloud-native SIEM and automated response platform |
