CVE-2021-45971 Explained : Impact and Mitigation

An issue was discovered in SdHostDriver in Insyde InsydeH2O with kernel 5.1 before 05.16.25, 5.2 before 05.26.25, 5.3 before 05.35.25, 5.4 before 05.43.25, and 5.5 before 05.51.25. A vulnerability exists in the SMM (System Management Mode) branch that registers a SWSMI handler that does not sufficiently check or validate the allocated buffer pointer (CommBufferData).

Understanding CVE-2021-45971

This CVE involves a vulnerability in Insyde InsydeH2O's SdHostDriver affecting specific kernel versions.

What is CVE-2021-45971?

The vulnerability in the SMM branch fails to properly validate the allocated buffer pointer (CommBufferData).

The Impact of CVE-2021-45971

The vulnerability could potentially be exploited by attackers to execute arbitrary code or cause denial of service.

Technical Details of CVE-2021-45971

The technical aspects of the vulnerability in Insyde InsydeH2O's SdHostDriver.

Vulnerability Description

Vulnerability in the SMM branch leading to insufficient validation of the allocated buffer pointer.

Affected Systems and Versions

Insyde InsydeH2O with kernel versions 5.1, 5.2, 5.3, 5.4, and 5.5 prior to certain build numbers.

Exploitation Mechanism

Attackers can exploit the vulnerability by registering a SWSMI handler without proper buffer pointer validation.

Mitigation and Prevention

Steps to mitigate and prevent exploitation of CVE-2021-45971.

Immediate Steps to Take

Apply patches or updates provided by the vendor.
Monitor for any unusual activities on the affected systems.

Long-Term Security Practices

Regularly update and patch systems to address known vulnerabilities.
Implement proper input validation mechanisms to prevent buffer overflow attacks.

Patching and Updates

Keep systems up to date with the latest software patches from Insyde.