What are three broad mechanisms that malware can use to propagate? What are four broad categories of payloads that malware may carry? What are typical phases of operation of a virus or worm? What mechanisms can a virus use to conceal itself? What is the difference between machine-executable and macro viruses? What means can a worm use to access remote systems to propagate? What is a drive-by-download and how does it differ from a worm? What is a logic bomb? Differentiate among the following: a backdoor, a bot, a keylogger, spyware, and a rootkit? Can they all be present in the same malware? List some of the different levels in a system that a rootkit may use. Describe some malware countermeasure elements. List three places malware mitigation mechanisms may be located. Briefly describe the four generations of antivirus software. How does behaviour-blocking software work? What is a distributed denial-of-service system?