CVE-2021-31426 Explained : Impact and Mitigation

This article provides insights into CVE-2021-31426, a vulnerability found in Parallels Desktop version 16.1.2-49151 that allows attackers to escalate privileges locally.

Understanding CVE-2021-31426

CVE-2021-31426 is a security vulnerability in Parallels Desktop that enables local attackers to elevate their privileges on affected systems. The flaw exists within the Parallels Tools component, leading to an integer overflow vulnerability.

What is CVE-2021-31426?

CVE-2021-31426 allows attackers with low-privileged access to execute arbitrary code within the kernel context, resulting in privilege escalation. The lack of proper validation of user-supplied data triggers an integer overflow, potentially leading to unauthorized access.

The Impact of CVE-2021-31426

The impact of CVE-2021-31426 is rated as high, with a CVSS base score of 8.8. Attackers can exploit this vulnerability to achieve high confidentiality, integrity, and availability impacts on the target system.

Technical Details of CVE-2021-31426

CVE-2021-31426 is classified under CWE-190: Integer Overflow or Wraparound. It has a low attack complexity and vector, requiring low privileges from the attacker while posing a high risk to system availability, integrity, and confidentiality.

Vulnerability Description

The vulnerability arises from the improper handling of user input, leading to an integer overflow when allocating a buffer within Parallels Tools. This flaw can be leveraged by attackers to escalate their privileges and execute malicious code in the kernel environment.

Affected Systems and Versions

Parallels Desktop version 16.1.2-49151 is confirmed to be affected by this vulnerability. Users of this version are at risk of privilege escalation and unauthorized execution of code within the system kernel.

Exploitation Mechanism

To exploit CVE-2021-31426, attackers must first gain the ability to run low-privileged code on the target system. By manipulating user-supplied data to trigger an integer overflow, attackers can then execute arbitrary code within the kernel, elevating their privileges successfully.

Mitigation and Prevention

Protecting systems against CVE-2021-31426 requires immediate action and long-term security practices to mitigate the risks effectively.

Immediate Steps to Take

Users are advised to apply security patches released by Parallels for addressing CVE-2021-31426. Additionally, restricting access and privileges to system resources can help reduce the vulnerability's exploitability.

Long-Term Security Practices

Implementing secure coding practices and regular security audits can enhance system resilience against similar vulnerabilities in the future. Continuous monitoring and timely updates are essential to maintain strong security posture.

Patching and Updates

Regularly check for security updates from Parallels and apply patches promptly to ensure that your system is protected against CVE-2021-31426 and other known vulnerabilities.