We were contacted by a company who have several dedicated servers using the Plesk interface provided by Parallels to manage the user interface (a common alternative to CPanel).  Their server had been taken down as it had been compromised via a recently released, critical vulnerability with Parallels Plesk affecting versions 7.6.1 – 10.3.1.

We received a call just after midnight from a server administrator who was having difficulties with his mail server - to the point that his international clients were unable to receive email at the middle of their peak period.  Nobody else picked up the phone ... we did!