Ubuntu Security Notice 3938-1 - Jann Horn discovered that pam_systemd created logind sessions using some parameters from the environment. A local attacker could exploit this in order to spoof the active session and gain additional PolicyKit privileges.
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Ubuntu Security Notice USN-3938-1
April 08, 2019
systemd vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.10
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS
Summary:
The systemd PAM module could be used to gain additional PolicyKit
privileges.
Software Description:
- systemd: system and service manager
Details:
Jann Horn discovered that pam_systemd created logind sessions using some
parameters from the environment. A local attacker could exploit this in
order to spoof the active session and gain additional PolicyKit
privileges.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 18.10:
libpam-systemd 239-7ubuntu10.12
Ubuntu 18.04 LTS:
libpam-systemd 237-3ubuntu10.19
Ubuntu 16.04 LTS:
libpam-systemd 229-4ubuntu21.21
Ubuntu 14.04 LTS:
libpam-systemd 204-5ubuntu20.31
In general, a standard system update will make all the necessary changes.
References:
https://usn.ubuntu.com/usn/usn-3938-1
CVE-2019-3842
Package Information:
https://launchpad.net/ubuntu/+source/systemd/239-7ubuntu10.12
https://launchpad.net/ubuntu/+source/systemd/237-3ubuntu10.19
https://launchpad.net/ubuntu/+source/systemd/229-4ubuntu21.21
https://launchpad.net/ubuntu/+source/systemd/204-5ubuntu20.31