==========================================================================
Ubuntu Security Notice USN-4269-1
February 05, 2020

systemd vulnerabilities
==========================================================================

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

- Ubuntu 19.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in systemd.

Software Description:
- systemd: system and service manager

Details:

It was discovered that systemd incorrectly handled certain PIDFile files.
A local attacker could possibly use this issue to trick systemd into
killing privileged processes. This issue only affected Ubuntu 16.04 LTS.
(CVE-2018-16888)

It was discovered that systemd incorrectly handled certain udevadm trigger
commands. A local attacker could possibly use this issue to cause systemd
to consume resources, leading to a denial of service. (CVE-2019-20386)

Jann Horn discovered that systemd incorrectly handled services that use the
DynamicUser property. A local attacker could possibly use this issue to
access resources owned by a different service in the future. This issue
only affected Ubuntu 18.04 LTS. (CVE-2019-3843, CVE-2019-3844)

Tavis Ormandy discovered that systemd incorrectly handled certain Polkit
queries. A local attacker could use this issue to cause systemd to crash,
resulting in a denial of service, or possibly execute arbitrary code and
escalate privileges. (CVE-2020-1712)

Update instructions:

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

Ubuntu 19.10:
  systemd                         242-7ubuntu3.6

Ubuntu 18.04 LTS:
  systemd                         237-3ubuntu10.38

Ubuntu 16.04 LTS:
  systemd                         229-4ubuntu21.27

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

References:
  https://usn.ubuntu.com/4269-1
  CVE-2018-16888, CVE-2019-20386, CVE-2019-3843, CVE-2019-3844,
  CVE-2020-1712

Package Information:
  https://launchpad.net/ubuntu/+source/systemd/242-7ubuntu3.6
  https://launchpad.net/ubuntu/+source/systemd/237-3ubuntu10.38
  https://launchpad.net/ubuntu/+source/systemd/229-4ubuntu21.27