CVE-2020-7451 Explained : Impact and Mitigation

In FreeBSD 12.1-STABLE before r358739, 12.1-RELEASE before 12.1-RELEASE-p3, 11.3-STABLE before r358740, and 11.3-RELEASE before 11.3-RELEASE-p7, a vulnerability exists due to improper initialization in handling TCP SYN-ACK or challenge TCP-ACK segments over IPv6, leading to disclosure of kernel memory over the network.

Understanding CVE-2020-7451

This CVE affects FreeBSD systems and can result in the exposure of sensitive kernel memory over the network.

What is CVE-2020-7451?

The vulnerability in FreeBSD versions mentioned allows for the disclosure of one byte of kernel memory over the network due to improper initialization of the Traffic Class field when handling specific TCP segments.

The Impact of CVE-2020-7451

The vulnerability could be exploited by an attacker to potentially access sensitive information from the kernel memory, compromising the security and integrity of the system.

Technical Details of CVE-2020-7451

The technical details of this CVE provide insight into the specific aspects of the vulnerability.

Vulnerability Description

The issue arises from the mishandling of TCP SYN-ACK or challenge TCP-ACK segments over IPv6, where the Traffic Class field is not properly initialized, leading to the exposure of one byte of kernel memory.

Affected Systems and Versions

FreeBSD 12.1-STABLE before r358739
FreeBSD 12.1-RELEASE before 12.1-RELEASE-p3
FreeBSD 11.3-STABLE before r358740
FreeBSD 11.3-RELEASE before 11.3-RELEASE-p7

Exploitation Mechanism

The vulnerability can be exploited by sending crafted TCP segments over IPv6 to trigger the improper initialization and disclose kernel memory over the network.

Mitigation and Prevention

Protecting systems from CVE-2020-7451 involves 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 activity that could indicate exploitation of the vulnerability.

Long-Term Security Practices

Regularly update and patch FreeBSD systems to mitigate potential security risks.
Implement network segmentation and access controls to limit exposure to external threats.

Patching and Updates

FreeBSD has released patches to fix the vulnerability. Ensure that systems are updated to the patched versions to prevent exploitation of CVE-2020-7451.