CVE-2021-38208 : Security Advisory and Response

A vulnerability has been identified in the Linux kernel before version 5.12.10, designated as CVE-2021-38208. This vulnerability, if exploited, could lead to a denial of service (NULL pointer dereference and BUG) by local unprivileged users. Here's what you need to know about this CVE.

Understanding CVE-2021-38208

This section provides insights into the nature and impact of CVE-2021-38208.

What is CVE-2021-38208?

The vulnerability exists in net/nfc/llcp_sock.c in the Linux kernel before 5.12.10. It allows local unprivileged users to trigger a denial of service by invoking a getsockname call subsequent to a specific bind call failure.

The Impact of CVE-2021-38208

Exploitation of this vulnerability could result in a NULL pointer dereference and a BUG, leading to a denial of service condition on affected systems.

Technical Details of CVE-2021-38208

This section delves into the technical aspects of CVE-2021-38208, outlining the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The flaw in the Linux kernel enables local unprivileged users to create a denial of service by executing a getsockname call following a particular bind call failure in net/nfc/llcp_sock.c.

Affected Systems and Versions

The vulnerability impacts Linux kernel versions prior to 5.12.10, exposing them to the risk of a denial of service attack by malicious local users.

Exploitation Mechanism

By leveraging the identified vulnerability, attackers with local unprivileged access can trigger a NULL pointer dereference and potentially cause a BUG, resulting in a denial of service.

Mitigation and Prevention

To safeguard systems against CVE-2021-38208, it is crucial to implement the following mitigation strategies.

Immediate Steps to Take

Immediate actions involve applying relevant security patches, monitoring system logs for unusual activities, and restricting untrusted access to vulnerable systems.

Long-Term Security Practices

Establish robust security practices including regular system updates, security training for personnel, and proactive threat hunting to enhance the overall security posture.

Patching and Updates

Ensure timely installation of patches released by the Linux kernel maintainers to address the vulnerability and prevent potential exploitation by threat actors.