=========================================================================Ubuntu Security Notice USN-3816-2
November 19, 2018
systemd vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
Summary:
systemd-tmpfiles could be made to change ownership of arbitrary files.
Software Description:
- 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:
systemd 239-7ubuntu10.4
Ubuntu 18.04 LTS:
systemd 237-3ubuntu10.9
Ubuntu 16.04 LTS:
systemd 229-4ubuntu21.9
After a standard system update you need to reboot your computer to make
all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-3816-2
https://ubuntu.com/security/notices/USN-3816-1
CVE-2018-6954
Package Information:
https://launchpad.net/ubuntu/+source/systemd/239-7ubuntu10.4
https://launchpad.net/ubuntu/+source/systemd/237-3ubuntu10.9
https://launchpad.net/ubuntu/+source/systemd/229-4ubuntu21.9
