CVE-2021-28191 Explained : Impact and Mitigation

A buffer overflow vulnerability has been identified in ASUS BMC's firmware due to a lack of string length verification in the firmware update function. This flaw could allow remote attackers to terminate the Web service abnormally by gaining privileged permissions. The affected products are numerous BMC firmware versions for various ASUS servers.

Understanding CVE-2021-28191

This CVE details a security issue in the ASUS BMC firmware, potentially leading to a buffer overflow due to inadequate input validation during firmware updates.

What is CVE-2021-28191?

The ASUS BMC firmware is impacted by a buffer overflow vulnerability that could be exploited by remote attackers to gain unauthorized privileged access and disrupt the Web service.

The Impact of CVE-2021-28191

The vulnerability poses a medium-severity risk with a CVSS base score of 4.9. Attackers can exploit this issue to cause a denial of service (DoS) condition by crashing the Web service.

Technical Details of CVE-2021-28191

The vulnerability arises from the ASUS BMC firmware's inadequate verification of user-supplied input during firmware updates, leading to a buffer overflow scenario.

Vulnerability Description

The Firmware update function in ASUS BMC's firmware Web management page fails to verify user input length, enabling a buffer overflow that could be exploited for unauthorized access.

Affected Systems and Versions

Multiple ASUS BMC firmware versions across various server models are affected by this vulnerability, including versions 1.09 to 1.15.6.

Exploitation Mechanism

Remote attackers can exploit this vulnerability by sending crafted input strings during the firmware update process, causing a buffer overflow and gaining unauthorized access.

Mitigation and Prevention

To address CVE-2021-28191, ASUS recommends updating the affected BMC firmware versions to secure releases to prevent potential exploitation.

Immediate Steps to Take

Users of ASUS servers with affected BMC firmware are advised to update to the patched versions provided by the vendor to mitigate the risk of exploitation.

Long-Term Security Practices

Regularly monitoring security advisories from ASUS and promptly applying firmware updates can help maintain the security of BMC firmware and prevent similar vulnerabilities.

Patching and Updates

ASUS has released updated BMC firmware versions for various server models to address the buffer overflow vulnerability. Users should ensure their systems are running the patched firmware versions to enhance security.