The AI Assistant and Its Access
Microsoft Copilot is designed to be your intelligent work partner, integrated across Microsoft 365 apps like Word, Excel, and Teams. It can draft documents, summarise meetings, and analyse data by pulling information from your organisation's digital ecosystem.
However, Copilot isn't a sentient being with its own security clearance; it's a tool that inherits the access rights of the user who is prompting it. This is a critical distinction. Copilot doesn't break through security barriers; it simply uses the keys it's given. This means it can only see and process data that the signed-in user already has permission to view. While this is a robust security design, it places immense importance on an organisation's existing data governance.
The Multiple Account Dilemma
In today's flexible work environment, it's common for an employee to be signed into multiple Microsoft accounts on the same device — for instance, a corporate account and a personal Microsoft 365 account. Microsoft has enabled a feature that allows Copilot access from one account to be used on documents from a different account. For example, an employee could use their personal Copilot Pro license to work on a corporate document if they are signed into both accounts. While this offers convenience, it introduces a potential for confusion and data crossover if not managed carefully. The key safeguard is that data protection policies are always based on the identity used to access the file, not the account providing the Copilot license. This ensures enterprise data protection remains tied to the work file, regardless of which account's Copilot is being used.
Permissions: The First and Last Line of Defense
The core issue isn't that Copilot will maliciously access restricted data. The real risk is that it will efficiently surface sensitive information that has been inadvertently overshared. If an employee has, over the years, accumulated access to old project folders, sensitive HR documents, or confidential financial reports they no longer need, Copilot can access that data just as easily as the employee can. A simple prompt like "Summarise the Q3 financial outlook" could pull information from a restricted file that the user shouldn't see but has permission to view. This makes file permissions the most critical component of a secure Copilot deployment. It's not about what Copilot can do, but about what your users can already access. Implementing a "least privilege" model—where users only have access to the data they absolutely need for their role—is paramount.
Steps to Secure Your AI-Powered Workplace
Companies rolling out Copilot must treat it as an opportunity to conduct a thorough data governance audit. The first step is to review and tighten permissions across SharePoint, OneDrive, and Teams. Identify and remediate over-permissioned resources, such as sites where "Everyone" has access to confidential files. Secondly, organisations should leverage tools like Microsoft Purview to apply sensitivity labels to data. These labels classify data as public, internal, or confidential, and the protection settings travel with the data, ensuring Copilot inherits and respects these boundaries. Furthermore, IT administrators can manage the multiple account access feature through policy settings, disabling it if it presents an unacceptable risk for their environment. Finally, user training is essential. Employees need to understand that Copilot is a powerful tool, but its output is based on the data it can access, making responsible data handling more important than ever.
