Legal Data Governance with Microsoft Purview 

Protecting privileged client data in a Microsoft 365 and Copilot environment. 

Confidentiality is the foundation of legal practice. Clients trust law firms with sensitive information ranging from litigation strategy and intellectual property to financial records and personal data. 

But the way legal teams collaborate has changed dramatically. 

Email, Teams, SharePoint, and OneDrive now power document drafting, discovery coordination, deal work, and client communication. Microsoft 365 has become the operational backbone for many law firms. 

That flexibility improves collaboration across offices, practice groups, and outside counsel. 

It also creates a reality many firms do not fully see: privileged documents can be shared more broadly than intended. 

Legal organizations remain prime targets for cybercrime and data exposure. According to industry research, over 74% of data breaches involve human error, including misdirected emails and improperly shared files. 

When sensitive client information moves this quickly, visibility and governance become critical. 

Privileged Documents May Already Be Shared in Ways You Cannot See 

Most law firms do not have a clear picture of where confidential client data exists across their Microsoft 365 environment. 

Documents move constantly during the life of a matter. Drafts are shared in Teams channels, attachments circulate through email, and files are stored in SharePoint libraries or downloaded into OneDrive for review. 

Over time, privileged information spreads across collaboration tools in ways that are difficult to track manually. 

Common locations include: 

• Email conversations containing legal advice or document drafts
• Teams channels used to coordinate litigation or transactions
• SharePoint matter folders containing contracts and filings
• OneDrive files used for drafting or document review
• Excel spreadsheets tracking discovery or financial analysis 

Without automated detection, many of these files remain invisible to IT and compliance teams until a problem occurs. 

Microsoft Purview automatically identifies sensitive legal content across email, Teams, and files. This provides law firms with visibility into where confidential information exists and how it is being shared across Microsoft 365. 

Before a firm can protect its client data, it first needs to understand where that data lives. 

One Misrouted Document Can Compromise a Client Matter

Most data exposure inside law firms is not intentional – it happens during normal collaboration: a discovery file shared with the wrong Teams channel, 
A document link sent to the wrong distribution list. 

Legal environments move quickly, and mistakes happen, but the consequences can be significant, and in some cases, firms may face sanctions, regulatory scrutiny, or reputational damage. 

According to IBM’s Cost of a Data Breach Report, the global average cost of a data breach reached $4.45 million. 

For law firms handling sensitive litigation, financial, or intellectual property data, the reputational impact can be even greater. 

Preventing accidental disclosure requires more than awareness – Microsoft Purview’s sensitivity labels automatically classify confidential legal documents and apply protection policies to them. 

These protections can:

• restrict who can access a document
• prevent external sharing
• apply encryption when sensitive content is detected 

Instead of relying on manual judgment for every file, governance policies help protect privileged information automatically. 

Protect Client Data Without Slowing Down Legal Work

Law firms face a constant balance between security and productivity. Attorneys, paralegals, and support teams operate under tight deadlines. If security controls interrupt their workflow, people will find ways around them.  Effective governance must protect sensitive data without disrupting legal work. 

Microsoft Purview applies protection automatically across Microsoft 365, so attorneys can continue using familiar tools like Outlook, Teams, and SharePoint while protections remain in place. 

The result is straightforward: Legal teams keep working the way they work, with guardrails protecting client information behind the scenes. 

Before Expanding Copilot, Know What It Can Access

AI tools are rapidly becoming more and more necessary in our workflows. And while AI boosts efficiency and offers powerful capabilities, it depends entirely on the permissions that already exist in your Microsoft 365 environment. 

Copilot does not decide what information it can access – it works within the permissions users already have. So if a SharePoint site has overly broad access or a document was shared too widely, Copilot can surface that information in its responses. In other words: Any governance gap becomes an AI access gap. 

Research shows 63% of organizations lacked AI governance policies to manage AI or prevent the proliferation of shadow AI, highlighting the importance of understanding permissions before deploying AI assistants. 

Before expanding Copilot across the firm, organizations should ensure their data governance policies are in place. Microsoft Purview helps close these gaps. 

Sensitivity labels, classification policies, and governance controls extend into how Copilot interacts with files. The protections applied to documents remain in place when AI tools access them. 

How cb20 Helps Law Firms Govern Microsoft 365 Data

cb20 helps law firms strengthen Microsoft 365 governance as part of a broader security and compliance strategy. Our team works with legal IT and compliance leaders to: 

• identify where sensitive legal data exists across Microsoft 365
• assess permissions and potential exposure risks
• implement Microsoft Purview governance policies
• deploy sensitivity labels and data protection controls
• prepare environments for secure AI adoption 

Every engagement is tailored to the firm’s practice areas, regulatory obligations, and collaboration patterns. The goal is simple: protect privileged client information without disrupting legal work. 

Know What Copilot Can Access Before It Does

AI capabilities are entering Microsoft environments quickly, so the real question is whether your data governance is ready. 

Microsoft Purview gives law firms the visibility and control needed to understand their data, reduce exposure risk, and safely adopt AI tools. 

cb20 helps organizations assess their Microsoft 365 environment, identify governance gaps, and implement the policies needed to support secure collaboration and AI adoption. 

Talk with cb20 about your Microsoft 365 data governance strategy.