CVE-2021-3428 : Security Advisory and Response

A detailed overview of CVE-2021-3428 focusing on the impact, technical details, and mitigation strategies.

Understanding CVE-2021-3428

This section delves into the essentials of CVE-2021-3428 to provide a comprehensive understanding.

What is CVE-2021-3428?

A flaw in the Linux kernel allows a local attacker to trigger a denial of service issue by corrupting an extent tree in a crafted ext4 filesystem. This manipulation can fabricate an integer overflow, leading to system crashes and availability threats.

The Impact of CVE-2021-3428

The vulnerability poses a significant risk as it enables a special user with local access to crash the system, thereby disrupting services and causing downtime.

Technical Details of CVE-2021-3428

This section focuses on the technical aspects of CVE-2021-3428, including the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The vulnerability lies in the ext4 filesystem within the Linux kernel. Specifically, the issue is present in

ext4_es_cache_extent

within

fs/ext4/extents.c

and stems from an integer overflow vulnerability.

Affected Systems and Versions

The vulnerability impacts Linux kernel versions before v5.9, making systems running on these versions susceptible to the exploitation of CVE-2021-3428.

Exploitation Mechanism

By corrupting the extent tree in a crafted ext4 filesystem, an attacker can trigger an integer overflow, leading to system crashes and a potential denial of service condition.

Mitigation and Prevention

In this final section, strategies to mitigate the risks posed by CVE-2021-3428 are discussed, focusing on immediate actions and long-term security practices.

Immediate Steps to Take

Administrators are advised to monitor security advisories related to the Linux kernel and apply patches promptly. Additionally, restricting access to privileged users can help mitigate the impact of this vulnerability.

Long-Term Security Practices

Implementing least privilege principles, regular security audits, and ensuring timely kernel updates are crucial for enhancing overall system security and resilience.

Patching and Updates

Regularly updating the Linux kernel to versions beyond v5.9 is imperative to safeguard systems against exploitation attempts targeting CVE-2021-3428. Patch management processes should be streamlined to ensure swift deployment of critical security updates.