Virus Damage Scenarious in OS Security

Virus

• Blackmail
• Denial of service as long as virus runs
• Permanently damage hardware
• Target a competitor's computer

            - Do harm
            - Espionage

• Intra-corporate dirty tricks

            - Practical joke
            - Sabotage another corporate officer's files

Worms vs Viruses

• Viruses require other programs to run
• Worms are self-running (separate process)
• The 1988 Internet Worm

            - Consisted of two programs
                   Bootstrap to upload worm
                   The worm itself
            - Exploited bugs in sendmail and finger
            - Worm first hid its existence
            - Next replicated itself on new machines
            - Brought the Internet (1988 version) to a screeching halt.