How To Mitigate CVE-2025-30381 - Microsoft Excel Remote Code Execution Vulnerability

CVE-2025-30381 is a critical vulnerability in Microsoft Excel that allows an unauthorized attacker to execute code locally through an out-of-bounds read. To protect systems from this vulnerability, follow the steps outlined below:

1. Update Microsoft Excel

Ensure that Microsoft Excel is updated to the latest version. Microsoft regularly releases security updates that address vulnerabilities. To check for updates:

• Open Excel and go to File > Account.

• Click on Update Options > Update Now.

2. Enable Automatic Updates

To ensure you receive the latest security patches, enable automatic updates:

• Go to File > Options.

• Select Trust Center > Trust Center Settings.

• Choose Automatic Updates and enable the option to receive updates automatically.

3. Limit Excel File Access

Restrict access to Excel files, especially those received from untrusted sources. Implement the following measures:

• Educate users about the risks of opening unknown Excel files.

• Use file sharing policies that restrict access to sensitive files.

4. Use Antivirus and Endpoint Protection

Deploy updated antivirus and endpoint protection solutions to detect and prevent the execution of malicious code. Ensure that:

• Real-time scanning is enabled.

• Regular scans are scheduled to identify potential threats.

5. Monitor and Audit Excel Usage

Implement monitoring tools to track the usage of Excel files within your organization. This includes:

• Logging access to sensitive Excel files.

• Reviewing logs for any unauthorized access attempts.

6. Disable Macros by Default

Macros can be a vector for executing malicious code. To enhance security:

• Go to File > Options > Trust Center.

• Select Trust Center Settings > Macro Settings.

• Choose the option to disable all macros without notification.

7. Educate Users

Conduct training sessions to inform users about the risks associated with opening Excel files and the importance of security practices. Topics should include:

• Identifying phishing attempts.

• Safe handling of email attachments.

8. Review Security Policies

Regularly review and update your organization’s security policies to ensure they address the latest threats and vulnerabilities. Consider:

• Implementing a policy for regular software updates.

• Establishing a response plan for security incidents.

References

For more information on this vulnerability, visit the official Microsoft Security Response Center page: Microsoft Security Response Center.