Artificial intelligence is rapidly transforming how organisations operate, and Microsoft 365 Copilot is a prime example. Operating within the Microsoft 365 framework, Copilot processes user prompts, retrieves data, and generates outputs in line with established privacy, security, and compliance controls. It leverages Azure OpenAI Service rather than publicly available OpenAI services, ensuring that customer content is not used for model training.
Importantly, Copilot does not expose organisational data outside the Microsoft 365 tenant; it operates within the organisation’s existing security and permission boundaries, ensuring that users can only access content they are already authorised to view. This preserves data residency, enforces access controls, and maintains full auditability in accordance with Microsoft 365 standards.
By integrating directly into Word, Outlook, Teams, and SharePoint, Copilot can summarise documents, answer queries, and surface organisational knowledge in seconds. However, this capability introduces a critical risk: if SharePoint permissions are not correctly configured, Copilot can expose sensitive information to users who were never intended to access it.
How Copilot Accesses Company Data
Copilot operates by querying the Microsoft Graph, which unifies data across Microsoft 365 services including SharePoint, OneDrive, Teams, Outlook, and Exchange. Rather than simply retrieving raw data in isolation, Copilot incorporates user context such as meetings, recent emails, and chat activity to generate relevant, contextualised responses.
When a user submits a prompt, Copilot searches only the content that the user is already authorised to access. It retrieves the most relevant information and generates a response accordingly. This enforces a fundamental security principle: Copilot cannot access or expose data beyond the user’s existing permissions.
While this model is secure by design, it assumes that underlying permissions are correctly configured. In practice, many organisations operate with over-permissive SharePoint environments. Over time, collaboration, file sharing, and convenience-driven decisions lead to excessive access rights, with employees often able to view far more information than intended.
Why AI Changes the Risk Landscape
Most companies have thousands of documents stored in SharePoint. Over the years, files are uploaded, documents are shared, teams change, and people leave the organisation. Permissions are often set quickly so people can collaborate easily. For example, someone might share a folder or grant view access to all staff, an entire department, or a project group that later grows much larger.
At the time, this might seem harmless. But as the organisation grows and more files are added, those permissions often remain in place. Eventually, far more people can access the files than originally intended.
Before AI assistants, discovering documents that had been incorrectly shared typically required effort. An employee would need to know the site or folder location, navigate the file structure, and manually search for specific files. Because of these barriers, many overshared documents remained effectively hidden. Copilot removes those barriers entirely by searching thousands of files in seconds and ensuring that incorrectly shared documents can surface instantly.
A Simple Example of the Risk
An HR team manager uploads a spreadsheet named Employee Salary Review 2025.xlsx containing employee salaries, bonuses, and promotion plans. The document is intended to be visible only to HR staff. During the upload process, however, the document library is accidentally shared with ‘Everyone except external users.’ As a result, every employee technically has permission to access the file. Before Microsoft Copilot, this mistake might never have been discovered. But once Copilot is enabled, an employee could ask, “What salary increases are planned this year?”
Copilot searches across Microsoft SharePoint, finds the HR document, and summarises the information. The employee now has access to sensitive compensation data, even though no one intentionally shared it with them.
Copilot does not introduce new access, but it significantly lowers the barrier to discovering and extracting the information.
Reducing Permission Risks Before Deploying Copilot
Microsoft 365 Copilot only surfaces organisational data to which individual users have at least view permissions. As a result, security is entirely dependent on how permissions are configured across Microsoft 365 services, particularly SharePoint. Common misconfigurations such as granting access to broad groups like “Everyone” can lead to oversharing. While these issues may go unnoticed in day-to-day use, Copilot makes them far more visible by enabling rapid discovery of accessible content. Ensuring that the right users and groups have appropriate access to content is critical, including when working with external users through Microsoft Teams shared channels.
When sharing documents, organisations can further mitigate risk by applying expiry dates to shared links or access permissions. This ensures that access is automatically revoked after a defined period, reducing the likelihood of unintended long-term exposure
This also applies to Copilot connectors, which indexes external data sources into Microsoft 365 Search and Copilot. To ensure secure and compliant access, it is important that the access permissions configured during setup reflect your organisation’s intended visibility model.
To manage connector permissions, navigate to Copilot > Connectors > Your Connections, select the relevant connector, and open the connection details pane. Within the Permissions section, confirm whether access is restricted to only people with access to the data source or set to visible to everyone. If permissions do not align with your intended model, the connection must be deleted and recreated using the custom setup process to explicitly define access controls.
More broadly, organisations should review their SharePoint security model before deploying Copilot at scale. This includes auditing sites, libraries, and folders to identify excessive or inherited permissions and aligning access with the principle of least privilege.
Final Thoughts
Artificial intelligence is becoming a standard part of workplace technology, and tools like Microsoft 365 Copilot have the potential to unlock tremendous value. As organisations adopt these AI tools, reviewing SharePoint permissions and information governance practices is no longer optional. It is a critical step in ensuring that productivity gains do not come at the expense of data security.