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Ubuntu Security Notice USN-3717-1
July 16, 2018

policykit-1 vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS
- Ubuntu 17.10
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in PolicyKit.

Software Description:
- policykit-1: framework for managing administrative policies and privileges

Details:

Tavis Ormandy discovered that PolicyKit incorrectly handled certain invalid
object paths. A local attacker could possibly use this issue to cause
PolicyKit to crash, resulting in a denial of service. This issue only
affected Ubuntu 14.04 LTS. (CVE-2015-3218)

It was discovered that PolicyKit incorrectly handled certain duplicate
action IDs. A local attacker could use this issue to cause PolicyKit to
crash, resulting in a denial of service, or possibly escalate privileges.
This issue only affected Ubuntu 14.04 LTS. (CVE-2015-3255)

Tavis Ormandy discovered that PolicyKit incorrectly handled duplicate
cookie values. A local attacker could use this issue to cause PolicyKit to
crash, resulting in a denial of service, or possibly escalate privileges.
This issue only affected Ubuntu 14.04 LTS. (CVE-2015-4625)

Matthias Gerstner discovered that PolicyKit incorrectly checked users. A
local attacker could possibly use this issue to cause authentication
dialogs to show up for other users, leading to a denial of service or an
information leak. (CVE-2018-1116)

Update instructions:

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

Ubuntu 18.04 LTS:
  libpolkit-backend-1-0           0.105-20ubuntu0.18.04.1

Ubuntu 17.10:
  libpolkit-backend-1-0           0.105-18ubuntu0.1

Ubuntu 16.04 LTS:
  libpolkit-backend-1-0           0.105-14.1ubuntu0.1

Ubuntu 14.04 LTS:
  libpolkit-backend-1-0           0.105-4ubuntu3.14.04.2

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

References:
  https://usn.ubuntu.com/usn/usn-3717-1
  CVE-2015-3218, CVE-2015-3255, CVE-2015-4625, CVE-2018-1116

Package Information:
  https://launchpad.net/ubuntu/+source/policykit-1/0.105-20ubuntu0.18.04.1
  https://launchpad.net/ubuntu/+source/policykit-1/0.105-18ubuntu0.1
  https://launchpad.net/ubuntu/+source/policykit-1/0.105-14.1ubuntu0.1
  https://launchpad.net/ubuntu/+source/policykit-1/0.105-4ubuntu3.14.04.2