CVE-2021-42321 Explained : Impact and Mitigation
Learn about CVE-2021-42321, a Remote Code Execution vulnerability affecting Microsoft Exchange Server. Find out the impact, affected systems, and mitigation steps to secure your environment.
Microsoft Exchange Server Remote Code Execution Vulnerability was published on 2021-11-09. This CVE affects Microsoft Exchange Server 2016 Cumulative Update 21, Microsoft Exchange Server 2019 Cumulative Update 10, Microsoft Exchange Server 2016 Cumulative Update 22, and Microsoft Exchange Server 2019 Cumulative Update 11 on x64-based Systems.
Understanding CVE-2021-42321
CVE-2021-42321 is a Remote Code Execution vulnerability affecting Microsoft Exchange Server.
What is CVE-2021-42321?
The CVE-2021-42321 vulnerability allows attackers to execute arbitrary code on the vulnerable server, potentially leading to a complete compromise of the system.
The Impact of CVE-2021-42321
The impact of this vulnerability is rated as HIGH with a CVSSv3.1 base score of 8.8, indicating a significant threat to the security of affected systems.
Technical Details of CVE-2021-42321
This section covers specific technical details of the vulnerability.
Vulnerability Description
The vulnerability allows remote attackers to execute arbitrary code on the target Exchange servers.
Affected Systems and Versions
- Microsoft Exchange Server 2016 CU21 (v15.01.0 to 15.01.2308.020)
- Microsoft Exchange Server 2019 CU10 (v15.02.0 to 15.02.0792.019)
- Microsoft Exchange Server 2016 CU22 (v15.0.0 to 15.01.2375.017)
- Microsoft Exchange Server 2019 CU11 (v15.02.0 to 15.02.0986.014)
Exploitation Mechanism
The vulnerability can be exploited by sending a specially crafted email to the vulnerable Exchange server, triggering the remote code execution.
Mitigation and Prevention
Protect your systems from CVE-2021-42321 with these mitigation strategies.
Immediate Steps to Take
- Apply the security updates provided by Microsoft for the affected Exchange Server versions.
- Monitor network traffic for any suspicious activity related to this vulnerability.
Long-Term Security Practices
- Regularly update and patch your systems to prevent known vulnerabilities.
- Implement network segmentation to limit the impact of potential future attacks.
Patching and Updates
- Microsoft has released security updates to address this vulnerability. Ensure timely application of these updates to secure your systems.