CVE-2023-6039 : Exploit Details and Defense Strategies

This CVE-2023-6039 involves a use-after-free vulnerability in the Linux Kernel's network sub-component, specifically in the

lan78xx_disconnect

function located in

drivers/net/usb/lan78xx.c

. The flaw allows a local attacker to trigger a system crash by detaching the LAN78XX USB device.

Understanding CVE-2023-6039

This section delves into the specifics of CVE-2023-6039.

What is CVE-2023-6039?

CVE-2023-6039 is a moderate-severity vulnerability in the Linux Kernel, allowing a local attacker to crash the system by exploiting a use-after-free flaw in the network component.

The Impact of CVE-2023-6039

The impact of this vulnerability is considered medium, with a CVSS base score of 5.5. It poses a high availability impact, but does not affect confidentiality or integrity. The privileges required for exploitation are low, with an attack complexity of low and vector string as "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H".

Technical Details of CVE-2023-6039

This section provides more technical insights into CVE-2023-6039.

Vulnerability Description

The vulnerability stems from a use-after-free flaw in the

lan78xx_disconnect

function in the

drivers/net/usb/lan78xx.c

file within the Linux Kernel. Exploiting this flaw allows a local attacker to crash the system by detaching the LAN78XX USB device.

Affected Systems and Versions

The affected products include Red Hat Enterprise Linux 6, 7, 8, 9, and Fedora. Notably, versions like "6.5-rc5" are unaffected, while specific package names under different Red Hat products are listed as unaffected or have workarounds available.

Exploitation Mechanism

The vulnerability can be exploited by a local attacker through detaching the LAN78XX USB device, leading to a use-after-free condition and subsequent system crash.

Mitigation and Prevention

In this section, strategies to mitigate the CVE-2023-6039 vulnerability are outlined.

Immediate Steps to Take

An immediate mitigation step is to prevent loading the affected module "lan78xx" onto the system until a fix is available. This can be achieved through a blacklist mechanism to ensure the driver is not loaded at boot time.

Long-Term Security Practices

Implementing regular security updates and staying informed about patches for the affected systems is crucial to maintain system integrity and protection against potential exploits.

Patching and Updates

Regularly check for patches and updates from the respective vendors, especially for Red Hat Enterprise Linux 6, 7, 8, 9, and Fedora, to address CVE-2023-6039 and enhance system security.

By following these mitigation steps and best security practices, organizations can safeguard their systems from the risks associated with CVE-2023-6039.