Debian 8: DLA-1762-1 Moderate: Systemd Local Access Control Issues

debian lts

April 24, 2019

Two vulnerabilities have been addressed in the systemd components systemd-tmpfiles and pam_systemd.so

Topics Covered

security advisory Debian environment variable systemd local access control

Summary

CVE-2017-18078

systemd-tmpfiles in systemd attempted to support ownership/permission
changes on hardlinked files even if the fs.protected_hardlinks sysctl
is turned off, which allowed local users to bypass intended access
restrictions via vectors involving a hard link to a file for which
the user lacked write access.

CVE-2019-3842

It was discovered that pam_systemd did not properly sanitize the
environment before using the XDG_SEAT variable. It was possible for
an attacker, in some particular configurations, to set a XDG_SEAT
environment variable which allowed for commands to be checked against
polkit policies using the "allow_active" element rather than
"allow_any".

For Debian 8 "Jessie", these problems have been fixed in version
215-17+deb8u12.

We recommend that you upgrade your systemd packages.

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these updates to your system and frequently asked questions can be