CVE-2021-41990 : What You Need to Know

CVE-2021-41990 involves a remote integer overflow vulnerability in the gmp plugin in strongSwan before 5.9.4, triggered by a crafted certificate with an RSASSA-PSS signature. This article provides insights into the impact of the CVE, technical details, and mitigation strategies.

Understanding CVE-2021-41990

What is CVE-2021-41990?

The gmp plugin in strongSwan prior to version 5.9.4 is susceptible to a remote integer overflow through specially crafted certificates containing RSASSA-PSS signatures. An attacker can exploit this issue by sending a malicious self-signed CA certificate as an initiator, potentially leading to remote code execution. However, successful exploitation of this vulnerability does not result in remote code execution.

The Impact of CVE-2021-41990

This vulnerability allows an attacker to trigger a remote integer overflow in strongSwan, leading to potential security breaches. Successful exploitation might enable an attacker to disrupt or gain unauthorized access to systems utilizing the affected software.

Technical Details of CVE-2021-41990

Vulnerability Description

The vulnerability arises from a remote integer overflow in the gmp plugin within strongSwan versions prior to 5.9.4. It occurs when a carefully crafted certificate is introduced to the system, containing a malicious RSASSA-PSS signature.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: All versions before 5.9.4

Exploitation Mechanism

The vulnerability can be exploited by an attacker sending a specifically crafted certificate with an RSASSA-PSS signature to the targeted system. This manipulation might result in a remote integer overflow, compromising the system's security.

Mitigation and Prevention

Immediate Steps to Take

Update strongSwan to version 5.9.4 or later to mitigate the vulnerability.
Regularly monitor vendor security advisories for patches and updates.
Implement network segmentation to limit the impact of potential attacks.

Long-Term Security Practices

Conduct regular security assessments and penetration testing to identify and address vulnerabilities.
Educate users and administrators about secure certificate management and validation practices.

Patching and Updates

Apply patches and updates provided by strongSwan promptly to ensure the latest security fixes are in place.