CVE-2021-43323 : Security Advisory and Response

An issue was discovered in UsbCoreDxe in Insyde InsydeH2O with kernel versions 5.5 before 05.51.45, 5.4 before 05.43.45, 5.3 before 05.35.45, 5.2 before 05.26.45, 5.1 before 05.16.45, and 5.0 before 05.08.45, allowing an attacker to escalate privileges to System Management Mode (SMM).

Understanding CVE-2021-43323

What is CVE-2021-43323?

A vulnerability in UsbCoreDxe in Insyde InsydeH2O allows attackers to take control of the execution flow of code operating in System Management Mode, leading to potential privilege escalation to SMM.

The Impact of CVE-2021-43323

Exploiting this vulnerability could result in an attacker gaining unauthorized access to SMM, potentially compromising system security and performing malicious activities.

Technical Details of CVE-2021-43323

Vulnerability Description

The vulnerability in UsbCoreDxe in Insyde InsydeH2O with specified kernel versions enables an SMM callout vulnerability, facilitating hijacking of code execution flow in System Management Mode.

Affected Systems and Versions

Insyde InsydeH2O with kernel versions 5.5 before 05.51.45
Insyde InsydeH2O with kernel versions 5.4 before 05.43.45
Insyde InsydeH2O with kernel versions 5.3 before 05.35.45
Insyde InsydeH2O with kernel versions 5.2 before 05.26.45
Insyde InsydeH2O with kernel versions 5.1 before 05.16.45
Insyde InsydeH2O with kernel versions 5.0 before 05.08.45

Exploitation Mechanism

The vulnerability allows threat actors to manipulate the execution path of code in SMM, paving the way for privilege escalation and unauthorized control over system functions.

Mitigation and Prevention

Immediate Steps to Take

Apply security patches provided by Insyde for the affected kernel versions.
Monitor system logs and activities for any suspicious behavior that may indicate an exploitation attempt.

Long-Term Security Practices

Regularly update firmware and software to the latest versions to mitigate known vulnerabilities.
Implement strong access controls and authentication mechanisms to prevent unauthorized access.

Patching and Updates

Insyde has released updated versions resolving the SMM callout vulnerability. Ensure timely installation of these patches to safeguard the system from exploitation.