CVE-2021-41991 Explained : Impact and Mitigation

A remote integer overflow vulnerability in strongSwan's in-memory certificate cache can lead to potential remote code execution.

Understanding CVE-2021-41991

What is CVE-2021-41991?

The vulnerability in strongSwan before version 5.9.4 triggers a remote integer overflow due to cache entry replacement, potentially allowing remote code execution.

The Impact of CVE-2021-41991

The vulnerability could enable attackers to exploit the cache system's weakness, leading to a slight possibility of remote code execution.

Technical Details of CVE-2021-41991

Vulnerability Description

The flaw arises in strongSwan's in-memory certificate cache, where an incorrect random entry selection process can result in a remote integer overflow.

Affected Systems and Versions

Product: StrongSwan
Versions affected: Versions prior to 5.9.4

Exploitation Mechanism

Attackers can manipulate the certificate cache by sending numerous requests with different certificates, causing an integer overflow and potentially leading to remote code execution.

Mitigation and Prevention

Immediate Steps to Take

Update strongSwan to version 5.9.4 or later to mitigate the vulnerability.
Monitor for any suspicious activities on the network related to certificate cache manipulations.

Long-Term Security Practices

Regularly update and patch software to prevent known vulnerabilities.
Implement network segmentation to limit the impact of potential breaches.
Conduct security assessments to identify and address weaknesses in the certificate management systems.

Patching and Updates

Regularly check for security updates and patches provided by strongSwan to address security vulnerabilities.