CVE-2021-21554 : Exploit Details and Defense Strategies

Dell PowerEdge R640, R740, R740XD, R840, R940, R940xa, MX740c, MX840c, and Dell Precision 7920 Rack Workstation BIOS contain a stack-based buffer overflow vulnerability affecting systems with Intel Optane DC Persistent Memory. This vulnerability could be exploited by a local malicious user with high privileges, potentially leading to a denial of service, arbitrary code execution, or information disclosure in UEFI or BIOS Preboot Environment.

Understanding CVE-2021-21554

This section delves into the details of CVE-2021-21554, highlighting its impact, technical description, affected systems, exploitation mechanism, and mitigation strategies.

What is CVE-2021-21554?

CVE-2021-21554 identifies a stack-based buffer overflow vulnerability in Dell PowerEdge and Precision BIOS firmware. This flaw could be leveraged by a local attacker with elevated privileges to execute arbitrary code or disrupt system services.

The Impact of CVE-2021-21554

The vulnerability's impact ranges from potential denial of service to information disclosure and arbitrary code execution. Attackers with local access and elevated privileges could exploit the flaw to compromise system integrity and confidentiality.

Technical Details of CVE-2021-21554

This section dives into the technical aspects of the vulnerability, detailing its description, affected systems, and how attackers can exploit it.

Vulnerability Description

The stack-based buffer overflow in Dell BIOS firmware poses a significant threat to systems with Intel Optane DC Persistent Memory. It opens the door for attackers to manipulate memory and potentially cause system instability or data leaks.

Affected Systems and Versions

Dell PowerEdge BIOS Intel 15G versions earlier than 2.9.4 are vulnerable to this exploit. Systems including R640, R740, R740XD, R840, R940, R940xa, MX740c, MX840c, and Dell Precision 7920 Rack Workstation are at risk.

Exploitation Mechanism

Local malicious users with high privileges can take advantage of the buffer overflow to disrupt system services, execute unauthorized code, or access sensitive information in the UEFI or BIOS Preboot Environment.

Mitigation and Prevention

To safeguard systems from CVE-2021-21554, immediate action and long-term security practices are crucial.

Immediate Steps to Take

Implementing security best practices, restricting access rights, and monitoring system logs can help mitigate the risk of exploitation. Promptly applying patches and updates is critical to address known vulnerabilities.

Long-Term Security Practices

Regular security assessments, employee training on cybersecurity awareness, and maintaining up-to-date security configurations are essential for long-term protection against such vulnerabilities.

Patching and Updates

Dell provides security updates and patches to address CVE-2021-21554. Ensuring the timely installation of these updates on affected systems is paramount to prevent exploitation and enhance system security.