CVE-2020-7459 : Exploit Details and Defense Strategies

In FreeBSD 12.1-STABLE before r362166, 12.1-RELEASE before p8, 11.4-STABLE before r362167, 11.4-RELEASE before p2, and 11.3-RELEASE before p12, a vulnerability exists that allows a malicious USB device to write beyond the end of an allocated network packet buffer.

Understanding CVE-2020-7459

This CVE involves a kernel out-of-bounds write vulnerability in FreeBSD.

What is CVE-2020-7459?

The CVE-2020-7459 vulnerability in FreeBSD allows a malicious USB device to write beyond the end of an allocated network packet buffer due to missing length validation code common to multiple USB network drivers.

The Impact of CVE-2020-7459

This vulnerability could be exploited by an attacker to potentially execute arbitrary code or cause a denial of service (DoS) on the affected system.

Technical Details of CVE-2020-7459

This section provides more technical insights into the CVE.

Vulnerability Description

The missing length validation code in multiple USB network drivers in FreeBSD versions mentioned allows a malicious USB device to write beyond the allocated network packet buffer.

Affected Systems and Versions

Affected Versions: FreeBSD 12.1-RELEASE before p8, 11.4-RELEASE before p2, 11.3-RELEASE before p12
Systems: FreeBSD 12.1-STABLE, 11.4-STABLE, and 11.3-RELEASE

Exploitation Mechanism

The vulnerability can be exploited by a malicious USB device to overwrite memory beyond the allocated buffer, potentially leading to arbitrary code execution or DoS.

Mitigation and Prevention

Protecting systems from CVE-2020-7459 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply the necessary patches provided by FreeBSD to address the vulnerability.
Monitor network traffic for any suspicious activities.
Restrict physical access to systems to prevent unauthorized USB device connections.

Long-Term Security Practices

Regularly update and patch FreeBSD systems to mitigate known vulnerabilities.
Implement network segmentation to limit the impact of potential attacks.
Educate users on safe USB device usage practices to prevent unauthorized access.

Patching and Updates

Ensure all FreeBSD systems are updated to versions that include the necessary patches to fix the vulnerability.
Stay informed about security advisories from FreeBSD to apply timely updates and patches.