CVE-2021-3719 : Exploit Details and Defense Strategies

A potential vulnerability in the SMI callback function that saves and restores boot script tables used for resuming from the sleep state in some ThinkCentre and ThinkStation models may allow an attacker with local access and elevated privileges to execute arbitrary code.

Understanding CVE-2021-3719

This CVE affects various versions of ThinkCentre and ThinkStation BIOS by Lenovo. It poses a risk of unauthorized code execution by an attacker with local access and elevated privileges.

What is CVE-2021-3719?

The vulnerability in the SMI callback function of certain Lenovo models could enable a malicious actor to run arbitrary code with elevated permissions on affected systems.

The Impact of CVE-2021-3719

With a CVSS base score of 6.7, this medium-severity vulnerability has a high impact on confidentiality, integrity, and availability. The attacker requires high privileges and local access to exploit this flaw.

Technical Details of CVE-2021-3719

The vulnerability is classified under CWE-20, relating to improper input validation. Here are further details:

Vulnerability Description

The flaw lies in the SMI callback function that manages boot script tables, enabling the execution of unauthorized code with elevated privileges.

Affected Systems and Versions

Lenovo ThinkCentre and ThinkStation BIOS models are impacted by this vulnerability across various versions.

Exploitation Mechanism

An attacker with local access and heightened privileges can exploit this flaw to execute arbitrary code, potentially compromising the affected systems.

Mitigation and Prevention

To address CVE-2021-3719, it is crucial to take immediate steps and implement long-term security practices.

Immediate Steps to Take

Users are advised to update the system firmware to the recommended version or newer as outlined in the Product Impact section on the Lenovo advisory LEN-67440.

Long-Term Security Practices

Incorporating strict access controls, regular security updates, and monitoring for suspicious activities can enhance the overall security posture.

Patching and Updates

Stay informed about security patches, firmware updates, and best practices to mitigate the risk of exploitation and ensure the protection of your Lenovo devices.