CVE-2019-11478 : Security Advisory and Response

A vulnerability was found in the Linux kernel's tcp_fragment function, affecting versions 4.4, 4.9, 4.14, 4.19, and 5.1. This vulnerability could be exploited by a remote attacker to launch a denial of service attack.

Understanding CVE-2019-11478

This CVE involves a vulnerability discovered by Jonathan Looney in the Linux kernel's handling of TCP Selective Acknowledgment (SACK) sequences.

What is CVE-2019-11478?

CVE-2019-11478 is a vulnerability in the Linux kernel's tcp_fragment function that could lead to a denial of service attack when exploited by a remote attacker.

The Impact of CVE-2019-11478

The vulnerability could allow a remote attacker to cause a denial of service by fragmenting the TCP retransmission queue implementation.

Technical Details of CVE-2019-11478

This section provides more technical insights into the vulnerability.

Vulnerability Description

The vulnerability in the Linux kernel's tcp_fragment function could result in a fragmented TCP retransmission queue, potentially leading to a denial of service.

Affected Systems and Versions

Linux kernel versions affected: 4.4, 4.9, 4.14, 4.19, 5.1

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Network
Availability Impact: Low
Base Score: 5.3 (Medium)
Privileges Required: None
User Interaction: None
Vector String: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Mitigation and Prevention

Here are the steps to mitigate and prevent exploitation of CVE-2019-11478.

Immediate Steps to Take

Update the Linux kernel to the fixed versions: 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11
Monitor for any unusual network activity that could indicate a denial of service attack

Long-Term Security Practices

Regularly update the Linux kernel to the latest stable releases
Implement network security measures to detect and prevent potential attacks

Patching and Updates

Apply the necessary patches provided by the Linux kernel maintainers to address the vulnerability