Data is one of the most valuable assets a business can have today. It is more than just information; it’s currency. An accidental email or unauthorized share can lead to severe consequences, including financial loss or legal action. This is where Data loss prevention in Microsoft 365 becomes crucial.
Microsoft 365 offers built-in tools designed to keep your sensitive business data safe from accidental or intentional leaks. This easy guide will walk you through what data loss prevention is, why it matters, and how you can start protecting your data right now.
What is Data Loss Prevention in Microsoft 365?
Data loss prevention (DLP) in Microsoft 365 is all about stopping sensitive information from leaving your organization. Think of your business’s data as water in a bucket. If there are holes, the water leaks out. DLP tools plug those holes to ensure your business data remains secure.
Sensitive data can be exposed through many channels in Microsoft 365, such as:
- Emails
- SharePoint documents
- OneDrive files
- Microsoft Teams chats
- Office applications like Word and Excel
DLP monitors these areas and keeps your information safe from unauthorized sharing.
Why Data Loss Prevention Matters?
Many small businesses focus primarily on protecting users and devices through measures such as multi-factor authentication and device security. While these measures are important, real risks often lie in unprotected data that they don’t stop, such as credit card details or healthcare data. In fact, the average cost of a data breach in 2024 was $4.88 million.
This is where Microsoft 365’s data loss prevention features step in. With DLP, you can:
- Prevent sensitive information from being shared externally
- Monitor activity around high-risk data
- Alert users in real time about policy violations
- Automatically block or restrict sharing of specific data
In short, Microsoft 365 empowers businesses to access essential DLP features to safeguard their most precious asset, i.e., their data.
Read more: Safeguard Your Microsoft 365 Tokens From Sneaky Thieves!
Microsoft 365 Licensing for Data Loss Prevention
Data loss prevention availability in Microsoft 365 depends on your subscription:
- Microsoft 365 Business Premium: Includes DLP for email, SharePoint, and OneDrive.
- Microsoft 365 E3 or E5 Licenses: Offer advanced coverage, including device protection and more granular controls.
Most small businesses will find Business Premium suitable as a starting point.
Identifying Sensitive Information with Microsoft Purview
Before you create DLP policies, you must define what counts as sensitive data in your organization. Microsoft 365 uses Sensitive Information Types (SITs) to identify data that needs protection. These SITs help the system recognize patterns, such as:
- Credit card numbers
- National insurance numbers
- Bank account details
- Passport or driver’s license numbers
In Microsoft Purview, Microsoft provides 225+ built-in sensitive information types for different regions. You can use these templates or create your own custom SITs, especially if you need to protect unique data like proprietary algorithms or medical research.
Creating a DLP Policy in Microsoft 365
Now that you have identified what to protect, it’s time to set up a DLP policy in Microsoft Purview.
Step 1: Use a Template
Start with a built-in template. Microsoft offers a variety, including “UK Financial Data” or “U.S. PII”. These templates already include a list of relevant SITs.
Step 2: Name Your Policy
Give your DLP policy a meaningful name and description (e.g., “UK Financial Data Protection”).
Step 3: Choose Where to Apply It
Decide which services you want the policy to cover. Most small businesses start with:
- Exchange Email
- SharePoint Sites
- OneDrive Accounts
You can also scope policies to specific users, groups, or sites, allowing for granular control.
Setting Policy Rules and Notifications
Once the scope is set, define what happens when a DLP rule is triggered. You can use:
- Policy Tips: Alert users in Word, Excel, or Outlook that they’re about to violate a policy.
- Email Notifications: Notify content owners, site admins, or compliance officers.
- Access Restrictions: Block content from being shared outside the organization.
Example: If someone attempts to email a credit card number externally, the system blocks the email and notifies both the sender and admin.
Access Control and Overrides
Microsoft 365 gives you flexibility over how strict the DLP policy should be:
- Block External Access Only: Allows internal sharing but blocks outsiders.
- Override Option: Let users override the block if they provide a business justification.
- False Positive Reporting: Let users flag an alert as incorrect, helping fine-tune future detections.
These options allow your organization to balance security with productivity, especially during the early stages of adoption.
Testing with Simulation Mode
Before rolling out your DLP policy company-wide, Microsoft recommends Simulation Mode:
- It won’t block any actions but will log potential violations.
- Users see tips, but they aren’t prevented from sharing.
- Great for testing impact and understanding user behavior.
After gathering insights, you can turn the policy on fully or automatically activate it after 15 days.
Example of DLP Policy in Action
Consider that a user named “Percy Pig” attempts to email credit card data outside the company. Once he hits send, Microsoft 365’s DLP policy detects the sensitive content and:
- Stops the email from being delivered
- Sends Percy a notification that the message violated a policy
- Logs the incident for review
This proves that the policy works as intended and prevents costly data leaks.
Conclusion
Did you know that 60% of small businesses experiencing significant data loss close within 6 months of the disaster?
Data loss prevention in Microsoft 365 isn’t just for large enterprises; it’s a critical tool for businesses of all sizes. When you use Microsoft Purview, identify sensitive information types, and apply well-scoped DLP policies, you can secure your most valuable asset. Start small, test with simulation mode, and grow your protection over time. With Microsoft 365, robust data loss prevention is built right in, so use it before your data walks out the door.
Looking to confidently implement data loss prevention and other Microsoft 365 security features? Sun IT Solutions specializes in managed IT services, cybersecurity, and cloud solutions across Toronto and beyond. With deep Microsoft 365 expertise, we help businesses identify sensitive data, configure effective DLP policies, and protect against insider threats and breaches. Serving small firms to enterprises, our team offers hands-on guidance, 24/7 support, and tailored security strategies.
Book a no-obligation consultation today to see how Sun IT Solutions can safeguard your data and empower your business with secure and modern IT infrastructure.
