CVE-2021-29649 : Exploit Details and Defense Strategies

An issue was discovered in the Linux kernel before version 5.11.11. The user mode driver (UMD) has a copy_process() memory leak due to a lack of cleanup steps, specifically in kernel/usermode_driver.c and kernel/bpf/preload/bpf_preload_kern.c, also known as CID-f60a85cad677.

Understanding CVE-2021-29649

This section will cover the details, impact, technical aspects, and mitigation strategies related to CVE-2021-29649.

What is CVE-2021-29649?

CVE-2021-29649 is a vulnerability found in the Linux kernel, affecting versions prior to 5.11.11. It involves a memory leak issue in the user mode driver (UMD) due to inadequate cleanup procedures.

The Impact of CVE-2021-29649

The vulnerability could potentially be exploited by attackers to trigger a denial of service (DoS) attack by consuming system memory resources, leading to system instability or crashes.

Technical Details of CVE-2021-29649

This section will delve into the specific technical aspects of the vulnerability.

Vulnerability Description

The vulnerability arises from a memory leak in the copy_process() function within the UMD, specifically within kernel/usermode_driver.c and kernel/bpf/preload/bpf_preload_kern.c.

Affected Systems and Versions

Systems running Linux kernel versions prior to 5.11.11 are vulnerable to this issue.

Exploitation Mechanism

Attackers could potentially exploit this vulnerability to exhaust system memory resources, leading to DoS conditions.

Mitigation and Prevention

Protecting systems against CVE-2021-29649 requires immediate action and long-term security practices.

Immediate Steps to Take

Update to the latest Linux kernel version (5.11.11 or later) to mitigate the vulnerability.
Monitor system resources for any unusual behavior that could indicate an ongoing exploit.

Long-Term Security Practices

Regularly update the kernel and system software to address known vulnerabilities.
Implement strict access controls and monitoring mechanisms to detect and prevent unauthorized access.

Patching and Updates

Keep track of security advisories and patches released by Linux distributions and vendors to apply timely updates and security fixes.