How Secure is Microsoft OneDrive for Business?

In August 2023, it was discovered that Microsoft OneDrive, which holds over half of all sensitive Microsoft Office documents, could be exploited by hackers through a ransomware attack. This exposed a significant security flaw between Windows and security systems, highlighting concerns about the safety of storing sensitive information on cloud services.

As we explore the security features of Microsoft OneDrive, a question arises: Can we trust that our data is truly secure in the cloud, or are we potentially putting ourselves at risk without even realizing it?

Is OneDrive Safe and Secure?

Besides serving as a cloud storage, Microsoft's OneDrive enables users to easily manage their documents, contacts, notes, passwords, and photos across all Windows devices. 

Due to this broad integration, Microsoft prioritizes securing your data with AES 256-bit standard for all uploads, downloads, and backups, providing a high level of encryption. Additionally, they offer two-factor authentication to further protect against unauthorized access. To ensure the safety of your information during transmission, OneDrive also implements the SSL/TLS encryption standard. 

But the question is, is this enough?

Common Security Concerns in OneDrive

1. Basic Data Loss Prevention (DLP) Capabilities

OneDrive for Business includes native Data Loss Prevention (DLP) policies, but they are relatively basic compared to more advanced, third-party solutions. The built-in DLP can identify and block common sensitive data types like credit card numbers and social security numbers, but it lacks the granularity required by organizations with complex, industry-specific data types or custom compliance needs.

Potential Issues:

• Limited predefined DLP templates that may not cover all sensitive data types.
• Inadequate customization options for organizations with specific data protection requirements.
• Insufficient real-time data remediation (e.g., automatic redaction or encryption based on data type).

Mitigation:

For more comprehensive data protection, consider using third-party DLP solutions, such as Strac, which provide granular policy creation, real-time detection, and remediation of sensitive data beyond OneDrive’s default capabilities.

2. Limited Protection Against Insider Threats

One of the major concerns for organizations is the risk posed by insider threats. While OneDrive for Business includes features like audit logs and access controls, it lacks advanced monitoring and detection capabilities for identifying malicious or negligent internal behavior. Employees or internal users with legitimate access to OneDrive can misuse or inadvertently share sensitive data without triggering sufficient alerts or protections.

Potential Issues:

• Insider actions, such as mass downloading, sharing files externally, or unauthorized file deletions, may go undetected.
• Difficulty distinguishing between legitimate and malicious internal actions.
• Limited capabilities for automated remediation of insider-related threats.

Mitigation:

To better protect against insider threats, organizations should consider using specialized security tools that integrate with OneDrive, such as insider threat detection platforms or behavioral analytics solutions. These tools monitor user activity for unusual patterns and can trigger alerts or block suspicious behavior in real-time.

3. Inconsistent Data Encryption for Metadata

While OneDrive encrypts data both at rest and in transit, file metadata (such as document titles, authors, and modification dates) may still be exposed, even if the content of the files is encrypted. This metadata could reveal sensitive information or inadvertently expose details that could be leveraged in a targeted attack.

Potential Issues:

• File metadata can sometimes contain sensitive information (e.g., file titles related to confidential projects).
• Limited control over the encryption and visibility of metadata within OneDrive.

Mitigation:

Organizations should ensure they enforce strict naming conventions and limit sensitive information stored in metadata. Additionally, leveraging third-party tools like Strac can help classify and protect metadata more effectively, limiting exposure risks.

4. External Sharing Vulnerabilities

One of the strengths of OneDrive for Business is its ease of external sharing, but this feature can also introduce security risks if not managed properly. While OneDrive offers some basic controls over external sharing, such as restricting who can access shared links or setting expiration dates, these controls may not be sufficient for organizations with high compliance or confidentiality requirements.

Potential Issues:

• Users may share sensitive files externally without adequate controls, leading to unintentional data exposure.
• Publicly accessible links may be created without administrator oversight.
• Limited visibility into what is shared externally and who has access to shared files.

Mitigation:

To address these risks, organizations should implement strict external sharing policies and leverage third-party DLP tools that automatically detect and block sensitive files from being shared externally. Solutions like Strac can automatically restrict or revoke sharing permissions for files containing sensitive data.

5. Limited Compliance Features for Complex Regulatory Needs

OneDrive for Business is compliant with many industry standards (such as GDPR, HIPAA, and SOC 2), but its native compliance features may not be sufficient for organizations with complex or highly regulated environments. The built-in audit logs and eDiscovery tools, while helpful, may lack the depth needed for comprehensive compliance management or long-term data retention.

Potential Issues:

• Limited audit log retention depending on the Microsoft 365 subscription plan.
• Difficulties in meeting industry-specific regulatory requirements without customization.
• Lack of long-term data retention and version control for audit purposes.

Mitigation:

Organizations can address these compliance gaps by integrating OneDrive with external compliance management tools or solutions like Microsoft 365 Advanced Compliance or Strac, which provide deeper auditing, extended log retention, and more robust compliance reporting tailored to specific regulations.

Best Practices for Maximizing OneDrive Security in Enterprises

Organizations can implement the best practices below to minimize cyber threats and breaches:

1. Implementing Data Loss Prevention

Implementing Data Loss Prevention (DLP) in OneDrive is essential for protecting sensitive information within your organization. By setting up DLP policies, you can monitor and control the sharing of sensitive data, ensuring compliance with various regulatory requirements.

2. Enforce Multi-Factor Authentication (MFA) for All Users

One of the most effective ways to protect accounts and prevent unauthorized access is by enabling Multi-Factor Authentication (MFA). MFA requires users to provide two or more forms of identification before accessing OneDrive, significantly reducing the risk of compromised credentials.

How to Implement:

• Enable MFA for all users, especially for those accessing sensitive data.
• Use Microsoft Authenticator or other supported MFA methods (SMS, phone calls, etc.) for added security.
• Configure Conditional Access policies to enforce MFA based on risk factors (e.g., location, device compliance).

3. Limit External Sharing and Set Expiration Dates

While external sharing is a powerful collaboration feature, it poses security risks if not tightly controlled. Enterprises should limit external sharing based on business needs and apply time-based controls to prevent indefinite access to shared data.

How to Implement:

• Disable public sharing or anonymous links to minimize the risk of data exposure.
• Require external users to authenticate before accessing shared files.
• Set automatic expiration dates for shared links to prevent long-term or forgotten access.
• Regularly review shared files and folders to ensure appropriate access levels.

4. Enable and Monitor Audit Logs

Audit logs provide a record of user activities in OneDrive, such as file access, sharing, and modification. Monitoring these logs can help detect suspicious activity, insider threats, and potential data breaches.

How to Implement:

• Enable Unified Audit Logs in the Microsoft 365 Security & Compliance Center to track file activities across OneDrive and other services.
• Use Azure Monitor or integrate with a SIEM (Security Information and Event Management) solution for real-time log monitoring and alerting.
• Set up automated alerts for unusual behaviors, such as mass file deletions, downloads, or unexpected external sharing.

5. Use Rights Management and Encryption

Rights management and encryption are essential for protecting sensitive data in OneDrive, ensuring that only authorized users can access and edit content.

How to Implement:

• Enable Microsoft Information Protection (MIP) and Azure Rights Management (RMS) to apply encryption and rights management to sensitive documents.
• Use MIP labels to classify sensitive files and automatically apply encryption, preventing unauthorized access.
• Ensure that encryption at rest and encryption in transit are enabled to protect data from interception or exposure.

6. Leverage Mobile Device Management (MDM) and Conditional Access

As employees increasingly access OneDrive on mobile devices, enterprises must implement controls to manage and secure mobile access. Mobile Device Management (MDM) solutions like Microsoft Intune ensure that only compliant devices can access OneDrive.

How to Implement:

• Use Microsoft Intune to enforce mobile security policies, including encryption, password protection, and device compliance.
• Restrict access to OneDrive on unmanaged or non-compliant devices.
• Use Conditional Access to limit access based on the device’s compliance status or security posture.
• Disable offline access to sensitive files on unmanaged mobile devices.

Introducing Strac OneDrive DLP Solution

Strac OneDrive DLP Solution offers real-time monitoring, automated data classification, redaction capabilities, intelligent alerting system, and compliance management. Strac simplifies compliance management, provides audit trails and reporting features, and offers a user-friendly and customizable interface. One of our clients on G2 stated,

Strac One Drive DLP solution protects businesses with the following core features:

1. Real-time monitoring: Stay ahead of data breaches on OneDrive

Strac OneDrive DLP solution keeps track of user activity, identifying and alerting any unauthorized or suspicious access to sensitive information in real time. With real-time monitoring and data classification features, Strac DLP protects confidential information on OneDrive.

2. Automated data classification: Simplifying data management on OneDrive

The Strac OneDrive DLP feature automatically categorizes data according to its level of sensitivity and compliance, effectively managing and tagging information to protect sensitive data.

3. Redaction capabilities: Safeguarding sensitive information on OneDrive

With Strac's advanced automated redaction capabilities, you can ensure the security and privacy of your data is well-maintained. This feature lets you easily remove or mask any sensitive information in documents before sharing or downloading them.

4. Intelligent alerting system: Proactive notifications on OneDrive

Strac OneDrive DLP provides efficient and reliable alerts for potential data leaks or breaches. It utilizes advanced machine learning algorithms to ensure high accuracy and reduce false positives, avoiding alert fatigue.

5. Compliance management: Ensuring regulatory compliance on OneDrive

Strac OneDrive DLP is a powerful compliance management tool specifically designed to ensure regulatory compliance on the OneDrive platform. Its ability to identify regulated data and enforce regulatory policies simplifies the process of staying compliant. Additionally, it offers useful features such as audit trails and detailed reporting to help demonstrate compliance during audits.

6. User-friendly and customizable: Tailoring Strac to your OneDrive needs

Strac is a highly customizable tool designed to cater to your specific needs on OneDrive. It offers a user-friendly interface with detailed reporting and analysis of all sensitive data stored on OneDrive, including information on shared files and their distribution over time. With Strac, you can easily manage and monitor your OneDrive data in a way that suits you best.