CVE-2021-33627 : Vulnerability Insights and Analysis

An issue was discovered in Insyde InsydeH2O 5.x, affecting FwBlockServiceSmm. The vulnerability lies in Software System Management Interrupt (SMI) services that use the Communicate() function of the EFI_SMM_COMMUNICATION_PROTOCOL without validating buffer address, potentially leading to unauthorized access to sensitive areas like SMRAM, MMIO, or OS kernel addresses.

Understanding CVE-2021-33627

This section provides insights into the nature and impact of the CVE-2021-33627 vulnerability.

What is CVE-2021-33627?

CVE-2021-33627 is a security vulnerability found in InsydeH2O firmware version 5.x, specifically affecting FwBlockServiceSmm. By exploiting this flaw, attackers can gain unauthorized access to critical system memory areas.

The Impact of CVE-2021-33627

The impact of this vulnerability could be severe as it allows attackers to manipulate sensitive system memory, potentially leading to arbitrary code execution or privilege escalation.

Technical Details of CVE-2021-33627

In this section, we delve into the technical aspects of the CVE-2021-33627 vulnerability.

Vulnerability Description

The vulnerability arises due to the lack of validation for buffer addresses in Software SMI services utilizing the Communicate() function of the EFI_SMM_COMMUNICATION_PROTOCOL.

Affected Systems and Versions

Insyde InsydeH2O firmware version 5.x is specifically affected by this vulnerability.

Exploitation Mechanism

Exploiting this vulnerability allows attackers to access and potentially manipulate sensitive areas of system memory, including SMRAM, MMIO, or OS kernel addresses.

Mitigation and Prevention

This section discusses the steps to mitigate and prevent exploitation of CVE-2021-33627.

Immediate Steps to Take

Immediately update the affected InsydeH2O firmware to a patched version provided by the vendor. Implement additional security measures to prevent unauthorized access to system memory.

Long-Term Security Practices

Regularly check for firmware updates and security advisories from Insyde and apply patches promptly. Conduct security assessments to identify and remediate similar vulnerabilities proactively.

Patching and Updates

Stay informed about security best practices and ensure timely patching of all software components to safeguard against potential exploits.