You have discovered that the ls, su and ps commands no longer function as expected. They do not return information in a manner similar to any other Linux system. Also, the implementation of Tripwire you have installed on this server is returning new hash values. Which of the following has most likely occurred?
A.
A trojan has attacked the system.
B.
A SQL injection attack has occurred.
C.
A spyware application has been installed.
D.
A root kit has been installed on the system.