Subject: Security Vulnerability in the Linux Kernel n_gsm line discipline CVE-2023-52564 / CVE-2023-6546

This document (000021437) is provided subject to the disclaimer at the end of this document.

Environment

For a comprehensive list of affected products please review the SUSE CVE announcements:

https://www.suse.com/security/cve/CVE-2023-52564.html
https://www.suse.com/security/cve/CVE-2023-6546.html

Situation

Security researchers have identified problems in the Linux Kernels n_gsm serial line discipline, which can be exploited by local attackers to gain kernel level root access.

Resolution

SUSE has applied a patch to the n_gsm line discipline that only allows it to be used as root user, and considers removing it from future kernel updates, service packs and products.

The last reported problems currently have no CVE assigned by the Linux Kernel CNA yet due to process reasons, but might assign one later. Hence the above CVE announcements point to the currently known CVEs only and will be updated as soon as possible.

SUSE has released fixed kernel packages for its distributions:

- SLES 15 SP4 LTSS, SLE Micro 5.3, 5.4: default kernel: 5.14.21-150400.24.116.1 and newer
- SLE Micro 5.3, 5.4: RT kernel: 5.14.21-150400.15.76.1 and newer

(more kernels are still in QA)

Status

Security Alert

Additional Information

Workaround:

rmmod n_gsm
echo "blacklist n_gsm" >> /etc/modprobe.d/99-n_gsm_blacklist.conf
echo "install n_gsm /bin/true" >> /etc/modprobe.d/99-n_gsm_blacklist.conf

To disallow auto-loading of tty line discipline modules in general:

sysctl dev.tty.ldisc_autoload = 0

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:000021437
Creation Date: 23-Apr-2024
Modified Date:23-Apr-2024
- SUSE Linux Enterprise Desktop
- SUSE Linux Enterprise Server
- SUSE Linux Enterprise Server for SAP Applications
- SUSE Manager
- SUSE Linux Enterprise Micro