CVE-2021-33656 Explained : Impact and Mitigation

This article provides details about CVE-2021-33656, a vulnerability found in the openEuler kernel affecting versions below 5.10.127.

Understanding CVE-2021-33656

This section will cover what CVE-2021-33656 is, its impact, technical details, and mitigation steps.

What is CVE-2021-33656?

CVE-2021-33656 is a vulnerability in the openEuler kernel that occurs when setting a font with malicious data using the ioctl command PIO_FONT, leading to out-of-bounds memory write.

The Impact of CVE-2021-33656

The vulnerability allows attackers to write memory out of bounds, potentially leading to system crashes, data corruption, or even remote code execution.

Technical Details of CVE-2021-33656

This section will delve into the vulnerability description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The flaw arises when the kernel writes memory out of bounds while setting fonts with malicious data using the PIO_FONT ioctl command.

Affected Systems and Versions

The vulnerability impacts the openEuler kernel versions below 5.10.127.

Exploitation Mechanism

Attackers can exploit this issue by crafting malicious font data and utilizing the PIO_FONT ioctl command to trigger out-of-bounds writes.

Mitigation and Prevention

Here, we outline immediate steps to take for protection, as well as long-term security practices and the importance of patching and updates.

Immediate Steps to Take

Users should apply patches promptly, restrict access to vulnerable systems, and monitor for any unusual activities.

Long-Term Security Practices

Implement secure coding practices, conduct regular security audits, and educate users on identifying and reporting suspicious activities.

Patching and Updates

Regularly update the openEuler kernel to versions beyond 5.10.127 or apply patches provided by the vendor to mitigate the CVE-2021-33656 vulnerability.