A systemd vulnerability has been reported which freezes systemd calls.

Systemd has been widely adopted in latest Linux Distributions like Redhat Enterprise Linux, Ubuntu, Debian, SUSE Linux Enterprise Servers. Systemd is the daemon that manages other daemons in Linux.

A zero sized message received in systemd notification socket will hang its pause system call. It will no longer be possible to start or stop services. The shutdown routine will get affected and it will not be possible to do a clean shutdown.

An exploited system can be checked with systemctl list-units command. If systemctl hangs or no result is available when running systemctl list-units, this can indicate an exploited system.

Some of the affected operating systems are

  1. Redhat Enterprise Linux v7
  2. Centos 7
  3. Ubuntu 15/16