CVE-2021-3759 : Exploit Details and Defense Strategies

A memory overflow vulnerability was found in the Linux kernel’s ipc functionality of the memcg subsystem, allowing a local user to starve resources and cause denial of service.

Understanding CVE-2021-3759

This CVE describes a memory overflow vulnerability in the Linux kernel, impacting system availability.

What is CVE-2021-3759?

CVE-2021-3759 is a flaw in the way a user calls the semget function multiple times, creating semaphores, leading to resource starvation and potential denial of service.

The Impact of CVE-2021-3759

The primary threat posed by this vulnerability is to system availability, potentially causing service disruption due to denied resources.

Technical Details of CVE-2021-3759

This section outlines the vulnerability's description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The vulnerability resides in the Linux kernel’s ipc functionality of the memcg subsystem, affecting how semaphores are created through the semget function.

Affected Systems and Versions

The vulnerability impacts the Linux kernel versions up to Linux kernel 5.15-rc1, prior to the fix implementation.

Exploitation Mechanism

An attacker can exploit this vulnerability by calling the semget function multiple times, triggering memory overflow and resource starvation.

Mitigation and Prevention

Learn how to address and prevent the exploitation of CVE-2021-3759 to ensure system security.

Immediate Steps to Take

Immediately apply patches and updates provided by Linux distributions to mitigate the vulnerability's impact on system availability.

Long-Term Security Practices

Implement robust security practices, such as least privilege access and regular security audits, to enhance overall system resilience.

Patching and Updates

Stay informed about kernel updates and security advisories to promptly apply relevant patches and ensure system protection.