USN-3816-3: systemd regression

27 November 2018

systemd regression

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 16.04 LTS

Summary

USN-3816-1 caused a regression in systemd-tmpfiles.

Software Description

  • systemd - system and service manager

Details

USN-3816-1 fixed vulnerabilities in systemd. The fix for CVE-2018-6954 caused a regression in systemd-tmpfiles when running Ubuntu inside a container on some older kernels. This issue only affected Ubuntu 16.04 LTS. In order to continue to support this configuration, the fixes for CVE-2018-6954 have been reverted.

We apologize for the inconvenience.

Original advisory details:

Jann Horn discovered that unit_deserialize incorrectly handled status messages above a certain length. A local attacker could potentially exploit this via NotifyAccess to inject arbitrary state across re-execution and obtain root privileges. (CVE-2018-15686)

Jann Horn discovered a race condition in chown_one(). A local attacker could potentially exploit this by setting arbitrary permissions on certain files to obtain root privileges. This issue only affected Ubuntu 18.04 LTS and Ubuntu 18.10. (CVE-2018-15687)

It was discovered that systemd-tmpfiles mishandled symlinks in non-terminal path components. A local attacker could potentially exploit this by gaining ownership of certain files to obtain root privileges. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2018-6954)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 16.04 LTS
systemd - 229-4ubuntu21.10

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

After a standard system update you need to reboot your computer to make all the necessary changes.

References