Severity

Medium

Vendor

Canonical Ubuntu

Versions Affected

• Canonical Ubuntu 16.04

Description

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)

Affected Cloud Foundry Products and Versions

Severity is unknown unless otherwise noted.

• Cloud Foundry BOSH xenial-stemcells are vulnerable, including:
  • 170.x versions prior to 170.12
  • 97.x versions prior to 97.39
  • All other stemcells not listed.

Mitigation

Users of affected products are strongly encouraged to follow one of the mitigations below:

• The Cloud Foundry project recommends upgrading the following BOSH xenial-stemcells:
  • Upgrade 170.x versions to 170.12
  • Upgrade 97.x versions to 97.39
  • All other stemcells should be upgraded to the latest version available on bosh.io.

References

• USN-3816-3