CVE-2021-28201 Explained : Impact and Mitigation

This article discusses the buffer overflow vulnerability in ASUS BMC's firmware affecting multiple products and versions, potentially exploited by remote attackers. Learn about the impact, technical details, and mitigation strategies.

Understanding CVE-2021-28201

CVE-2021-28201 is a vulnerability in ASUS BMC's firmware that allows remote attackers to exploit a buffer overflow in the Service configuration-1 function of the Web management page. The lack of input validation by users can lead to a critical security risk.

What is CVE-2021-28201?

The vulnerability arises from a lack of string length verification in the firmware, enabling attackers to execute arbitrary code and disrupt the targeted service. This can result in service termination and potential unauthorized access.

The Impact of CVE-2021-28201

With a CVSS base score of 4.9 (Medium severity), this vulnerability poses a threat to the availability of affected systems. The exploit's low attack complexity and network vector increase the risk of unauthorized access.

Technical Details of CVE-2021-28201

The vulnerability, categorized under CWE-120 (Buffer Overflow), affects various ASUS BMC firmware versions for different server models. The affected products include ASMB9-iKVM, RS700A-E9-RS4, ESC4000 G4X, and many more.

Vulnerability Description

The Service configuration-1 function fails to validate user-entered string lengths, leading to a buffer overflow that can be leveraged by attackers to gain privileged access and disrupt services.

Affected Systems and Versions

Multiple ASUS server models running BMC firmware versions such as 1.09, 1.10.0, 1.14.1, 1.15.1, and others are vulnerable to this exploit. Prompt updates are essential to mitigate the risk.

Exploitation Mechanism

Remote attackers exploit the buffer overflow by sending specially crafted requests to the vulnerable Web management page, causing the service to terminate abnormally and potentially allowing unauthorized access.

Mitigation and Prevention

To address CVE-2021-28201, ASUS recommends updating affected BMC firmware to secure versions. Implementing immediate patches, following robust security practices, and prioritizing software updates are essential to prevent potential exploits.

Immediate Steps to Take

Update BMC firmware versions for affected ASUS server models to mitigate the buffer overflow vulnerability. Regularly monitor security advisories and apply patches promptly.

Long-Term Security Practices

Enforce strict input validation mechanisms, perform regular security audits, conduct penetration testing, and stay informed about emerging threats to enhance overall system security.

Patching and Updates

Refer to the ASUS Product Security Advisory for the list of affected products and their corresponding firmware versions. Maintain a proactive approach to firmware updates and security measures to safeguard against potential vulnerabilities.