CVE-2019-11477 : Vulnerability Insights and Analysis

An integer overflow vulnerability in the Linux kernel's handling of TCP Selective Acknowledgments (SACKs) was discovered by Jonathan Looney from Netflix. This vulnerability could be exploited by a remote attacker to cause a denial of service.

Understanding CVE-2019-11477

This CVE identifies a critical security issue in the Linux kernel related to TCP_SKB_CB(skb)->tcp_gso_segs.

What is CVE-2019-11477?

The CVE-2019-11477 vulnerability is an integer overflow in the Linux kernel when processing TCP Selective Acknowledgments (SACKs), potentially leading to a denial of service.

The Impact of CVE-2019-11477

The vulnerability has a CVSS base score of 7.5 (High severity) with a low attack complexity. It could allow a remote attacker to disrupt the availability of affected systems.

Technical Details of CVE-2019-11477

This section provides more in-depth technical information about the vulnerability.

Vulnerability Description

The flaw arises from an integer overflow in the TCP_SKB_CB(skb)->tcp_gso_segs value within the Linux kernel, triggered by the processing of TCP SACKs.

Affected Systems and Versions

The vulnerability affects the following Linux kernel versions:

4.4 (less than 4.4.182)
4.9 (less than 4.9.182)
4.14 (less than 4.14.127)
4.19 (less than 4.19.52)
5.1 (less than 5.1.11)

Exploitation Mechanism

By exploiting this vulnerability, a remote attacker could potentially launch a denial of service attack on the affected systems.

Mitigation and Prevention

Protecting systems from CVE-2019-11477 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply the necessary patches provided by the Linux kernel to mitigate the vulnerability.
Monitor for any unusual network activity that could indicate exploitation of the flaw.

Long-Term Security Practices

Regularly update the Linux kernel to the latest stable versions to ensure all security patches are applied.
Implement network security measures to detect and prevent potential attacks targeting this vulnerability.

Patching and Updates

Ensure that all affected systems are updated with the stable kernel versions 4.4.182, 4.9.182, 4.14.127, 4.19.52, and 5.1.11, or have the necessary commit (3b4929f65b0d8249f19a50245cd88ed1a2f78cff) applied.