Security vulnerability: CVE-2022-25636, a heap out of bounds write in the Linux kernel.

This document (000020615) is provided subject to the disclaimer at the end of this document.

Environment

For a comprehensive list of affected products and package versions, please see the SUSE CVE announcement:
https://www.suse.com/security/cve/CVE-2022-25636.html

Situation

An out-of-bounds (OOB) memory access flaw was found in the netfilter kernel subsystem. This security bug could lead an attacker with a user account on the system to escalate his privilege (LPE) or crash the system (DoS).

Resolution

Installing the updated packages provided by SUSE is sufficient to fix the problem. Please use the following command to search for the specific patch information.

zypper lp -a --cve=CVE-2022-25636

After a kernel update a restart is required. Unless using SUSE Linux Enterprise Live Patching extension, for which SUSE provides the live patch to fix this vulnerability allowing to patch the kernel without shutting down the system and reducing the need for planned downtime and increasing service availability.

Status

Security Alert

Additional Information

Workaround

Please note that user namespaces are required to run Linux containers. If containers are in use, the following workaround is not suitable.

The workaround can be implemented by deny unprivileged users to run unshare(CLONE_NEWUSER) or unshare(CLONE_NEWNET):

echo 0 > /proc/sys/user/max_user_namespaces

this change will be lost as soon as the operating system is rebooted. To make a permanent change, set the following value in the "/etc/sysctl.d/" directory:

echo "user.max_user_namespaces = 0" > /etc/sysctl.d/disable_user_namespaces.conf

then the system configuration files need to be reloaded:

sysctl --system

References:

https://bugzilla.suse.com/show_bug.cgi?id=1196299
https://www.suse.com/security/cve/CVE-2022-25636.html
https://nickgregory.me/linux/security/2022/03/12/cve-2022-25636
https://github.com/Bonfee/CVE-2022-25636

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

Document ID:000020615
Creation Date: 16-Mar-2022
Modified Date:16-Mar-2022
- SUSE Linux Enterprise Desktop
- SUSE Linux Enterprise Real Time
- SUSE Linux Enterprise Server
- SUSE Linux Enterprise Server for SAP Applications
- SUSE Open Stack Cloud
- SUSE Manager
- SUSE Linux Enterprise Micro