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Monthly TuxCare Update – October 2021

November 2, 2021 - TuxCare PR Team

Welcome to the next installment of our monthly news round-up, brought to you by TuxCare. We have developed live patching solutions that minimise maintenance workload and disruption while at the same time maximising security and uptime for your systems.

In this latest monthly overview, we’ll start as usual with a round-up of the latest CVEs patched by the TuxCare Team. We’ll also bring you the latest valuable tips and advice and some exciting videos created by the TuxCare Team.


1. CVEs Disclosed in October
2. Enterprise Linux Security Video Podcasts
3. The latest CentOS 8 End Of Life News
4. TuxCare Blog: Editor’s Pick

CVEs Disclosed in October

October saw the disclosure of a series of vulnerabilities that affect Ubuntu 20.04 Hardware Enablement Stacks (HWE) and Amazon Web Services (AWS).

The first, designated CVE-2020-3702, affects the Atheros Ath9k Wi-Fi driver within the Kernel. A potential race condition between concurrent threads could cause unexpected and attacker exploitable behaviour. Principally affecting Snapdragon-based wireless adapters, the vulnerability could allow a system attack using the wireless connection as an ingress vector.

The next, designated CVE-2021-3732, affects file access controls allowing unprivileged access to protected data.

The next, designated CVE-2021-3739, affects the BTRFS code within the Kernel, where a hijacked process running with CAP_SYS_ADMIN privileges can be used to launch a denial of service.

The next, designated CVE-2021-3743, was found in the implementation of the Qualcomm IPC Router protocol. Unvalidated metadata can be exploited to access sensitive information, disrupt processing, or launch a denial of service.

The next, designated CVE-2021-3753, affects the virtual terminal (VT) device used for local access to a system through the console. A race condition can be exploited to cause an out-of-bounds read error that can be leveraged for unauthorised information disclosure.

The next, designated CVE-2021-38166, affects the BPF subsystem of the Kernel. An attacker with CAP_SYS_ADMIN privileges can cause an integer overflow to produce an out-of-bounds write in the HashTab code. This vulnerability can be leveraged to initiate arbitrary code execution, disrupt processing, or launch a denial of service. This kernel code has been the subject of other recent vulnerabilities that have been previously mentioned extensively.

The next, designated CVE-2021-40490, affects the EXT4 codebase and is another exploitable race condition that can be leveraged to launch a denial of service. There is a known path towards privilege escalation for this vulnerability in this widely deployed code, so its potential significance is considered very high.

The final vulnerability, designated CVE-2021-42008, was found in the “decode_data” function of the “hamradio” networking driver. An attacker with CAP_SYS_ADMIN privileges can use this to cause an out-of-bounds write. This vulnerability can be remotely leveraged to obtain root access or launch a denial of service.

Enterprise Linux Security Video Podcasts

The TuxCare team’s Enterprise Linux Security podcast continues to offer in-depth topical explanations for the latest hot topics and foundational concepts. Co-hosted by Learn Linux TV’s Jay LaCroix and TuxCare’s very own Joao Correia, the next two episodes are now available to view.

You can watch the fifth episode that discusses how attackers think and operate here: Enterprise Linux Security Episode 05 – The “Attacker” Mindset – YouTube

Also available is the sixth episode that discusses deployment images here: Enterprise Linux Security Episode 06 – Image Defaults – YouTube

These video podcasts discussing Linux security issues are essential viewing for anyone involved in managing Linux-based enterprise systems.

The latest CentOS 8 End Of Life News

In September, we announced the launch of our Extended Lifecycle Support for CentOS 8, following the sudden announcement of its end of life. It’s now only sixty days until CentOS 8’s end of life, with the end coming in that period between Christmas and New Year when no one wants to be managing a major OS migration. If you’re still undecided about how to proceed at this very late stage, check out this video by Jay from the LearnLinuxTV for the complete list of options. Don’t forget that our support package includes our live patching service for critical system components and 24/7 support.

TuxCare Blog: Editor’s Pick

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