CVE-2021-42008 : Security Advisory and Response

A slab out-of-bounds write vulnerability in the Linux kernel before version 5.13.13 can result in root access for processes with CAP_NET_ADMIN capability.

Understanding CVE-2021-42008

This CVE involves a specific function in the Linux kernel that allows unauthorized access to the root level, posing a significant security risk.

What is CVE-2021-42008?

The decode_data function in drivers/net/hamradio/6pack.c in the Linux kernel before 5.13.13 experiences a slab out-of-bounds write. Malicious input from a process possessing the CAP_NET_ADMIN capability can potentially lead to obtaining root access.

The Impact of CVE-2021-42008

Exploitation of this vulnerability can result in unauthorized access to the root account, allowing malicious actors to take control of the affected system.

Technical Details of CVE-2021-42008

This section delves into the specific technical aspects of the CVE.

Vulnerability Description

The vulnerability stems from a slab out-of-bounds write issue in the decode_data function within a particular driver in the Linux kernel.

Affected Systems and Versions

Linux kernel versions before 5.13.13 are affected
Processes with the CAP_NET_ADMIN capability are particularly vulnerable

Exploitation Mechanism

Unauthorized processes with CAP_NET_ADMIN capability can exploit this flaw
Malicious input can trigger the out-of-bounds write, potentially leading to root access

Mitigation and Prevention

Protecting systems from the CVE-2021-42008 vulnerability is crucial for maintaining security.

Immediate Steps to Take

Update the Linux kernel to version 5.13.13 or above
Restrict the CAP_NET_ADMIN capability to trusted processes only

Long-Term Security Practices

Regularly monitor and update the kernel for any security patches
Implement strong access control and privilege separation mechanisms

Patching and Updates

Apply security patches promptly to address known vulnerabilities
Stay informed about security advisories and updates from reliable sources