New Ubuntu Security Fixes for Linux Kernel Vulnerabilities

Rohan Timalsina

December 6, 2023 - TuxCare expert team

Ubuntu has recently released security fixes for Ubuntu 22.04 LTS and Ubuntu 23.04, addressing several vulnerabilities found in the Linux kernel. Exploiting these vulnerabilities could lead to a denial of service (system crash) or potentially arbitrary code execution on the system.

In this blog, we delve into the details of these vulnerabilities, including their CVE, severity score, and the security issues in the kernel.

Linux Kernel Security Fixes

CVE-2023-25775 (Cvss 3 Severity Score: 9.8)

Ivan D Barrera, Christopher Bednarz, Mustafa Ismail, and Shiraz Saleem identified a vulnerability in the InfiniBand RDMA driver within the Linux kernel. The driver failed to correctly check for zero-length STAG or MR registration, potentially enabling a remote attacker to execute arbitrary code.

CVE-2023-31085 (Cvss 3 Severity Score: 5.5)

Yu Hao found a flaw in the UBI driver of the Linux kernel, where improper validation for MTD with zero erasesize during device attachment. This could be exploited by a local attacker to cause a denial of service.

CVE-2023-45871 (Cvss 3 Severity Score: 9.8)

One of the Ubuntu security fixes includes a patch for a vulnerability in the Linux kernel’s Intel(R) PCI-Express Gigabit (igb) Ethernet driver. The driver incorrectly validated received frames larger than the set MTU size, creating a buffer overflow issue. An attacker could take advantage of this issue to crash the system or potentially execute arbitrary code.

CVE-2023-5090 (Cvss 3 Severity Score: 5.5)

Maxim Levitsky identified a flaw in the KVM nested virtualization (SVM) implementation for AMD processors in the Linux kernel. The issue arose from improper handling of x2AVIC MSRs, allowing an attacker in a guest VM to cause a denial of service by crashing the host kernel.

CVE-2023-5345 (Cvss 3 Severity Score: 7.8)

A vulnerability was found in the SMB network file sharing protocol implementation in the Linux kernel, where certain error conditions were not properly handled. This resulted in a use-after-free vulnerability that a local attacker could exploit to crash the system or potentially execute arbitrary code.

CVE-2023-5633 (Cvss 3 Severity Score: 7.8)

Murray McAllister found a use-after-free vulnerability in the Linux kernel’s VMware Virtual GPU DRM driver. This resulted due to the incorrect handling of memory objects when storing surfaces. A local attacker in a guest VM could use this flaw to cause a denial of service or potentially execute arbitrary code.

Conclusion

It is essential to update your Ubuntu 23.04 and Ubuntu 22.04 LTS systems to fix these security problems, and then a system reboot is required. For rebootless and automated patching, you can utilize TuxCare’s KernelCare Enterprise for live patching the Linux kernels in all popular Linux Enterprise distributions, including Ubuntu, CentOS, RHEL, Rocky Linux, AlmaLinux, Oracle Linux, and more.

The sources for this article can be found on USN-6502-1.

Summary