A server is performing slowly, and users are reporting issues connecting to the application on that server. Upon investigation, the server administrator notices several unauthorized services running on that server that are successfully communicating to an external site. Which of the following are MOST likely causing the issue? (Choose two.)

A. Adware is installed on the users' devices
B. The firewall rule for the server is misconfigured
C. The server is infected with a virus
D. Intrusion detection is enabled on the network
E. Unnecessary services are disabled on the server
F. SELinux is enabled on the server