CVE-2021-46283 : Security Advisory and Response

CVE-2021-46283 relates to a vulnerability in the Linux kernel before version 5.12.13 that allows local users to launch a denial of service attack. This occurs due to a missing initialization, leading to a NULL pointer dereference and general protection fault.

Understanding CVE-2021-46283

This section delves into the details of the vulnerability.

What is CVE-2021-46283?

The vulnerability, identified as nf_tables_newset in net/netfilter/nf_tables_api.c, facilitates a denial of service attack by local users. The issue arises from the absence of initialization for nft_set_elem_expr_alloc, enabling a local user to manipulate a netfilter table expression in their namespace.

The Impact of CVE-2021-46283

The vulnerability can lead to a denial of service (NULL pointer dereference and general protection fault) when exploited by a local user.

Technical Details of CVE-2021-46283

Exploring the technical aspects of the CVE.

Vulnerability Description

The flaw in nf_tables_newset in the Linux kernel prior to 5.12.13 allows local users to exploit it, causing a denial of service due to missing initialization for nft_set_elem_expr_alloc.

Affected Systems and Versions

Systems running Linux kernel versions before 5.12.13

Exploitation Mechanism

Local users can manipulate a netfilter table expression in their namespace, leading to a denial of service.

Mitigation and Prevention

Understanding how to mitigate and prevent the vulnerability.

Immediate Steps to Take

Update the Linux kernel to version 5.12.13 or later.
Monitor and restrict user privileges to mitigate the risk of exploitation.

Long-Term Security Practices

Regularly update and patch all software components on the system.
Implement user privilege separation to limit the impact of potential vulnerabilities.

Patching and Updates

Apply patches provided by Linux kernel maintainers to address the vulnerability.