systemd - security update

The manager_dispatch_notify_fd function in systemd allowed local users to cause
a denial of service (system hang) via a zero-length message received over a
notify socket, which caused an error to be returned and the notification
handler to be disabled.

For Debian 7 Wheezy, these problems have been fixed in version
44-11+deb7u5.

We recommend that you upgrade your systemd packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: <https://wiki.debian.org/LTS&gt;