are usually spread by users downloading viral programs from public bulletin boards or exchanging floppy disks containing an infection

are beneficial for program

both (a) and (b)

none of these

Trojan Horse

trap doors

both 1) Trojan Horse and 2) trap doors

none of these

prevention

practice of safe computing

purchasing unopened software from vendors

avoiding free or pirated copies from public sources

A code segment that misuses its file is called Trojan horse

good for file accessing

both (a) and (b)

none of these

the system can check for suspicious patterns of activity in an attempt to detect a security violation

a time sharing a system that counts the number of incorrect passwords given

both 1) the system can check for suspicious patterns of activity in an attempt to detect a security violation and 2) a time sharing a system that counts the number of incorrect passwords given

none of these