Page 299 - DCAP103_Principle of operating system

Principles of Operating Systems

Notes Even once better protocols are in hand, convincing the world to accept them represents its own
set of headaches. No central governing body rules the Internet, and standards bodies have been
ineffective at getting parties to adopt adequate security specifications. The situation is further
complicated by the fact that national governments differ in their views of how the Internet
should be run, and many key Internet players argue against any government intervention at all.
What is clear is that cybersecurity deserves immediate, sustained attention. As noted in the
PITAC report, “the IT infrastructure of the U.S. is highly vulnerable to terrorist and criminal
attacks. It is imperative that we take action before the situation worsens and the cost of inaction
becomes even greater.”

Operating systems provide the fundamental mechanisms for securing
computer processing. Since the 1960s, operating systems designers have
explored how to build “secure” operating systems.

9.3 Program Threats

Threats originated from viruses, which are strictly speaking programs that replicate themselves
without your knowledge. The earliest known viruses were simply annoying, appearing as a
MS-DOS program in folders of infected computers, transferred through floppy disks. They
became dangerous when these viruses started to spoof and infect valid files. With the advent
of the Internet, viruses further evolved into worms that spread through networks. Worms not
only propagate themselves, but also “carry” other malicious files in them, such as Trojan horses,
which drop malicious files in computers.

Threats make affected the system.

9.3.1 Types of Threats
Worms: This malicious program category largely exploits operating system vulnerabilities to
spread itself. The class was named for the way the worms crawl from computer to computer,
using networks and e-mail. This feature gives many worms a rather high speed in spreading
themselves.
Viruses: Programs that infected other programs, adding their own code to them to gain control
of the infected files when they are opened. This simple definition explains the fundamental
action performed by a virus-infection.
Trojans: Programs that carry out unauthorized actions on computers, such as deleting information
on drives, making the system hang, stealing confidential information, etc. This class of malicious
program is not a virus in the traditional sense of the word (meaning it does not infect other
computers or data). Trojans cannot break into computers on their own and are spread by hackers,
who disguise them as regular software. The damage that they incur can exceed that done by
traditional virus attacks by several fold.
Spyware: Software that collects information about a particular user or organization without
their knowledge. You might never guess that you have spyware installed on your computer.
Riskware: Potentially dangerous applications include software that has not malicious features
but could form part of the development environment for malicious programs or could be used
by hackers as auxiliary components for malicious programs.
Rootkits: Utilities used to conceal malicious activity. They mask malicious programs to keep

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