CVE-2021-43256 Explained : Impact and Mitigation
Learn about the CVE-2021-43256 Microsoft Excel Remote Code Execution Vulnerability, its impact, and mitigation steps. Protect affected systems with security patches and best practices.
A Microsoft Excel Remote Code Execution Vulnerability was disclosed on December 14, 2021.
Understanding CVE-2021-43256
This CVE involves a Remote Code Execution vulnerability in Microsoft Excel.
What is CVE-2021-43256?
The CVE-2021-43256 is a high-severity vulnerability that allows an attacker to execute arbitrary code remotely, potentially leading to unauthorized actions.
The Impact of CVE-2021-43256
The vulnerability can have a significant impact on systems, potentially compromising data integrity and system confidentiality.
Technical Details of CVE-2021-43256
This section provides detailed technical information about the CVE.
Vulnerability Description
The vulnerability enables remote attackers to execute malicious code on the targeted system.
Affected Systems and Versions
- Microsoft Office Online Server versions less than 16.0.10381.20001
- Microsoft Office 2019 version 19.0.0
- Microsoft 365 Apps for Enterprise version 16.0.1
- Microsoft Office LTSC 2021 version 16.0.1
- Microsoft Excel 2016 versions less than 16.0.5254.1000
- Microsoft Excel 2013 SP1 versions less than 15.0.5407.1000
- Microsoft Office Web Apps Server 2013 SP1 version 15.0.5407.1000
Exploitation Mechanism
The vulnerability can be exploited by enticing a user to open a specially crafted Excel file or through other means of interaction, potentially leading to code execution.
Mitigation and Prevention
Protect your systems against CVE-2021-43256 with the following measures:
Immediate Steps to Take
- Apply security patches from Microsoft promptly.
- Educate users about the risks of opening untrusted Excel files.
- Monitor for any suspicious Excel file activities.
Long-Term Security Practices
- Implement strong email filtering to block malicious attachments.
- Regularly update security software and conduct vulnerability assessments.
- Enforce the principle of least privilege to restrict user access.
Patching and Updates
Regularly check for security updates from Microsoft and apply them to ensure protection against the vulnerability.