GIAC Exam GSLC Topic 1 Question 69 Discussion

You work as a Network Administrator for Infosec Inc. The company has a Windows 2003-based server. You have installed McAfee antivirus as well as anti-spyware software on the server. One day, you come to know that not only have the security applications running on the server (including software firewalls, anti-virus, and anti-spyware) been disabled, but the anti-virus and anti-spyware definitions have also been deleted. You suspect that this is due to malware infection. Which of the following types of malware is the most likely cause of the issue?