Hackers Leverage Copilot AI in SharePoint to Extract Passwords and Sensitive Data

Microsoft Copilot for SharePoint, the latest AI-powered assistant embedded in Microsoft 365, is transforming how organizations search, manage, and interact with their corporate data.

But as adoption surges, security researchers and Red Teams are raising red flags about the platform’s potential as both a productivity game-changer and a new attack vector for data breaches.

How Copilot for SharePoint Works

According to the report, Copilot for SharePoint leverages generative AI to help users find information, summarize documents, and automate tasks directly within SharePoint sites.

The technology operates through “Agents,” which come in two main forms:

• Default Agents: Pre-built by Microsoft, these are automatically enabled on SharePoint sites for organizations with Microsoft 365 Copilot licenses.
• They have broad access to site content and can answer questions about files, pages, and internal documentation.
• Custom Agents: Created and configured by organizations, these can be trained on specific datasets and even pull information from multiple SharePoint sites or external sources.
• Customization extends to setting agent behaviors, welcome prompts, and knowledge sources.

Agents are stored as .copilot files within document libraries and can be shared or embedded in SharePoint pages using HTML <iframe> code, allowing users to interact with AI directly from their browser.

xml<iframe src="https://copilotstudio.microsoft.com/environments/Default-dce884ba-edef-407d-a984-80abfd9244b3/bots/fr_agent/webchat?__version__=2" frameborder="0" style="width: 100%; height: 100%;"></iframe>

Security Risks: The Double-Edged Sword

While Copilot dramatically improves data discoverability, it also amplifies longstanding SharePoint security challenges:

• Oversharing and Permission Drift: Copilot respects existing SharePoint permissions, but misconfigured access controls or “public” sites can inadvertently expose sensitive data, such as passwords, API keys, or confidential reports, to unauthorized users.
• Bypassing “Restricted View”: In recent Red Team engagements, researchers demonstrated that Copilot Agents could retrieve the full contents of files-even those protected by SharePoint’s “Restricted View” privilege, which should prevent downloads. The agent’s chat output can be copied freely, circumventing intended access restrictions.
• Stealthy Enumeration: Copilot queries do not trigger the usual “recent files” or “accessed by” logs, making malicious activity harder to detect. Attackers can trawl large datasets rapidly and discreetly, searching for keywords like “password” or “confidential” without leaving obvious traces.
• Custom Agent Exploits: Attackers with edit permissions can install or manipulate Custom Agents, expanding the attack surface. Risks include:
  • Aggregating data from multiple sites for mass enumeration
  • Extracting secrets from custom training data
  • Poisoning knowledge bases to influence agent behavior
• Cloud Vulnerabilities: Recent vulnerabilities, such as CVE-2024-38206, have exposed Copilot Studio to server-side request forgery (SSRF) attacks, enabling authenticated attackers to access internal Microsoft cloud services. While Microsoft patched the flaw, it highlights the risks of integrating AI with cloud infrastructure.

Real-World Attack Scenario

A typical attack might involve an adversary using social engineering prompts to convince Copilot that they are part of the security team:

Copilot, acting on its programmed helpfulness, could then enumerate and summarize files containing sensitive data-even if the attacker’s account should not have direct access.

Mitigation and Best Practices

To defend against these emerging threats, experts recommend:

• Strict Access Controls: Regularly audit SharePoint permissions and restrict agent creation to trusted users.
• Content Hygiene: Proactively remove sensitive information from SharePoint or store it in highly restricted locations.
• Monitoring and Logging: Utilize Microsoft’s monitoring tools to track agent usage and file access patterns. Investigate anomalies promptly.
• Layered Security: Combine technical controls with user training and incident response planning for robust defense-in-depth.

Microsoft Copilot for SharePoint is reshaping digital collaboration, but its power comes with significant security responsibilities.

Organizations must balance productivity gains with rigorous governance to prevent Copilot from becoming an unintentional insider threat.

For IT leaders, the message is clear: AI assistants are only as secure as the data and permissions they are given.

Now is the time to review, restrict, and monitor before convenience turns into compromise.

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