USN-3816-2: systemd vulnerability

19 November 2018

systemd-tmpfiles could be made to change ownership of arbitrary files.

Releases

Packages

  • systemd - system and service manager

Details

USN-3816-1 fixed several vulnerabilities in systemd. However, the fix for
CVE-2018-6954 was not sufficient. This update provides the remaining fixes.

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 18.10
Ubuntu 18.04
Ubuntu 16.04

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

References

Related notices