February 2016

How many ways to transfer the data between input/output devices and main memory?

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Here I will discuss about the transferring data………… </div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%;">How many ways to
transfer the data between input/output devices and main memory?</span></b></div>
<div class="MsoNormal">
There are different<span style="mso-spacerun: yes;"> 
</span>ways to transfer data between i/o devices and main memory..</div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l1 level1 lfo1; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri;"><span style="mso-list: Ignore;">(1)<span style="font: 7.0pt "Times New Roman";">    </span></span></span><span dir="LTR"></span>Using interrupt</div>
<div class="MsoListParagraphCxSpLast" style="mso-list: l1 level1 lfo1; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri;"><span style="mso-list: Ignore;">(2)<span style="font: 7.0pt "Times New Roman";">    </span></span></span><span dir="LTR"></span>Using DMA(Direct Memory Access)</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%;">Interrupts:</span></b></div>
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<span style="mso-tab-count: 2;">                                </span>An
interrupt are the signals that is sent to CPU by an i/o device and also sent to
the i/o device by CPU. When CPU is interrupted in the execution of the program
then it stop its current all activities such as execution of the program. After
this, it transfer the control to interrupting device to check the interrupt.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglOE0hYi3333TKM4PKWVZdQKjKkXB26fvfxW1prnCSiBczO7_HZKlGaT_nRbErjH0UiEix4kLgzVjuKG9_NAPxLwaVT14feNjc5imDzgYfY4K2bcUw_OO9W31ufiFEVyJHHgyhXKyuw9M/s1600/images+%25281%2529.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglOE0hYi3333TKM4PKWVZdQKjKkXB26fvfxW1prnCSiBczO7_HZKlGaT_nRbErjH0UiEix4kLgzVjuKG9_NAPxLwaVT14feNjc5imDzgYfY4K2bcUw_OO9W31ufiFEVyJHHgyhXKyuw9M/s1600/images+%25281%2529.jpg" /></a></div>
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<span style="mso-tab-count: 2;">                                </span>Interrupt
are one that is most commonly used scheme to handle i/o devices. In this
scheme, the CPU normally called processer issues a command signals to the
input/output devices for i/o operation. When the device is ready , it generate
the interrupt signals to the processer(CPU). The processing exit all other
operations when it receives the interrupt signals for that device. Then it
perform the input/output operations.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Advantages of interrupt:</span></b></div>
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<span style="mso-tab-count: 3;">                                                </span>The
main advantages of the interrupt scheme is that there is no required of the
additional hardware. It is easy to and implement.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Disadvantages of interrupt:</span></b></div>
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The disadvantages of this interrupt scheme is that it reduces
the overall performance of the computer system.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%;">DMA: </span></b></div>
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<span style="mso-tab-count: 1;">                </span>DMA
stands for <i style="mso-bidi-font-style: normal;">Direct memory access</i>. DMA
scheme use a special hardware component to perform the task. This hardware is
called the DMA controller. In this scheme the data transferring between input/output
devices and main memory is takes place without the involvement of the CPU
(processer). To complete this operation, the CPU send the request to the DMA
controller to perform the input/output operation such as transferring the data
from input/output devices. Then CPU (processer) continue to perform their other
tasks. When the data transferring is complete with DMA, then the DMA controller
send an interrupt signals to CPU. Thus, CPU is involved only at the beginning and
the end of the data transferring.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Advantages of DMA:</span></b></div>
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<span style="mso-tab-count: 3;">                                                </span>The
main advantages of the DMA is that the processor does not have to wait the
completion of the tasks of i/o operations. The performance of the computer
system increased.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Disadvantages of the DMA:</span></b></div>
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<span style="mso-spacerun: yes;"> </span>The main
disadvantages of the DMA controller is that it is more complex and more
hardware is require to needed to implement this scheme.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%;">CPU Registers</span></b></div>
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The storage area that is used to store a small data is
called <i style="mso-bidi-font-style: normal;">register.</i><span style="mso-spacerun: yes;">  </span>These are the high speed memories. These memories
are use to store data and instruction during the program’s execution. <span style="mso-spacerun: yes;"> </span>The CPU consist of many types of the
registers. Each of the registers is use for special purposes. The size of these
registers is 2, 4, 8, 16 or more. The large size of these registers increase
the performance of the CPU (processer).</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%;">Types of Special Purpose Registers:</span></b></div>
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There are different special purpose registers that are used
to perform different task during executions of the program. These registers are
as follow:</div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l0 level1 lfo2; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri;"><span style="mso-list: Ignore;">1.<span style="font: 7.0pt "Times New Roman";">       </span></span></span><span dir="LTR"></span>Program counter register</div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo2; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri;"><span style="mso-list: Ignore;">2.<span style="font: 7.0pt "Times New Roman";">       </span></span></span><span dir="LTR"></span>Instruction register</div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo2; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri;"><span style="mso-list: Ignore;">3.<span style="font: 7.0pt "Times New Roman";">       </span></span></span><span dir="LTR"></span>Memory address register</div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l0 level1 lfo2; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri;"><span style="mso-list: Ignore;">4.<span style="font: 7.0pt "Times New Roman";">       </span></span></span><span dir="LTR"></span>Memory buffer register</div>
<div class="MsoListParagraphCxSpLast" style="mso-list: l0 level1 lfo2; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri;"><span style="mso-list: Ignore;">5.<span style="font: 7.0pt "Times New Roman";">       </span></span></span><span dir="LTR"></span>Stack register</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Program counter register (PC):</span></b></div>
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<span style="mso-tab-count: 4;">                                                                </span>The
program counter register is use to control the sequence of the instruction that
are comes or fetched from the memory. This register also store the address of
the next instruction that will be fetched form the memory. when the instruction
is fetched form the main memory then the value of PC is incremented. This
register is also known as <i style="mso-bidi-font-style: normal;">Instruction
pointer register</i>. </div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Instruction Register (IR):</span></b></div>
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<span style="mso-tab-count: 3;">                                                </span>Those
instructions are stored in the instruction register that are fetched from the
main memory. The instruction that is in IR, the control unit take these
instruction and decodes it and then executer these instruction one by one.</div>
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<span style="mso-tab-count: 1;">                </span>“The
next registers will be discuss in Next lecture”<span style="mso-tab-count: 2;">                           </span></div>

How many ways to transfer the data between input/output devices and main memory?

Normal 0 false false false EN-US X-NONE AR-SA

17 Feb 2016

Instruction set and its types

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Here I will discuss about the <u>execution</u> of the<span style="mso-spacerun: yes;">  </span><b>instructions</b> of the <u>computer system</u></div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Instruction set</span></b></div>
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<span style="mso-tab-count: 1;">                </span>A set
of all <i>instruction that a computer execute</i> at one time is called <i style="mso-bidi-font-style: normal;">instruction set</i>. Different types of CPUs
(processer) have different instruction set. Usually a CPU (processer) can
executer 80-120 instruction.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Types of instruction set:</span></b></div>
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<span style="mso-tab-count: 2;">                                </span>There
are different types of <b>instruction</b> set are as follow:</div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l1 level1 lfo1; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">1.<span style="font: 7.0pt "Times New Roman";">      
</span></span></span><span dir="LTR"></span>Data transfer instruction</div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l1 level1 lfo1; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">2.<span style="font: 7.0pt "Times New Roman";">      
</span></span></span><span dir="LTR"></span>Arithmetic and logical
instruction </div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l1 level1 lfo1; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">3.<span style="font: 7.0pt "Times New Roman";">      
</span></span></span><span dir="LTR"></span>I/O instruction </div>
<div class="MsoListParagraphCxSpLast" style="mso-list: l1 level1 lfo1; text-indent: -.25in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">4.<span style="font: 7.0pt "Times New Roman";">      
</span></span></span><span dir="LTR"></span>Control transfer instruction<span style="mso-spacerun: yes;">  </span><br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgILMjn1KlpyILGqVwZD30ufcJhz3fASm8yh8BAoGQY3MoBFl9T6TJiVoNg3kpsLKbL3g8JZK9k92Dh8c4-mM4mODVKBbLC4fi1bc7G7byW5PVzzItyoEvYd6GceS1eYqIA0dMJiOWVQfg/s1600/download+%25281%2529.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Instruction set" border="0" height="299" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgILMjn1KlpyILGqVwZD30ufcJhz3fASm8yh8BAoGQY3MoBFl9T6TJiVoNg3kpsLKbL3g8JZK9k92Dh8c4-mM4mODVKBbLC4fi1bc7G7byW5PVzzItyoEvYd6GceS1eYqIA0dMJiOWVQfg/s400/download+%25281%2529.jpg" title="Instruction set" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Instruction set</td></tr>
</tbody></table>
</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Data transfer instructions:</span></b></div>
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<span style="mso-tab-count: 3;">                                                </span>A
types of instruction set which is used to transfer data from one unit of the
computer system to another is called data transfer instruction.<span style="mso-spacerun: yes;">  </span>The CPUs provide different instruction for
the data transferring. A programmer or user can use these instruction to
transfer data from RAM to CPU registers and also back to RAM or to transfer the
data to the output devices.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Arithmetic and logical instructions:</span></b></div>
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<span style="mso-tab-count: 4;">                                                                </span>A<span style="mso-spacerun: yes;">  </span>type of instruction set which is use to
perform arithmetic instructions on the data is called arithmetic instructions.
Arithmetic operations means all mathematical operation like addition,<span style="mso-spacerun: yes;">  </span>subtraction, multiplication,<span style="mso-spacerun: yes;">  </span>and division. All the arithmetic instructions
are executed by ALU.</div>
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<span style="mso-tab-count: 2;">                                </span>Those
instructions that are used to perform an logical operation on the data are
called logical instructions. The logical operation means that to compare the
two values. All the logical operations are also executed by ALU.</div>
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<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">I/O instructions:</span></b></div>
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<span style="mso-tab-count: 2;">                                </span>A
type of instruction set which is use to write and read data to and from the I/O
devices are called I/O instructions. The I/O devices <span style="mso-spacerun: yes;"> </span>are also know as peripheral devices. In
peripheral devices keyboard, mouse, monitor and disks etc. The user or
programmer can use these instructions to perform I/O operations.</div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Control transfer instructions:</span></b></div>
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<span style="mso-tab-count: 3;">                                                </span>A
type of instruction set which is use to transfer the execution control from one
part of the computer to another during execution of the program is called
control transfer instruction. These instructions are also used to execute or
ignore a statement or set of statement after testing a condition.<span style="mso-spacerun: yes;">  </span>Similarly, these instructions are also use to
execute the statement repeatedly for a specified number of time. </div>
<div align="center" class="MsoNormal" style="text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Operating system</span></b></div>
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A collection of system software that control and co-ordinate
the overall operations of the computer system is called operating system. For
to do work, a computer need an operating system. Without operating system a
computer cannot work. Without operating system a computer is like a car that
have no fuel.</div>
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An operating system can perform different kind of operation.
It is used</div>
<div class="MsoListParagraphCxSpFirst" style="margin-left: .75in; mso-add-space: auto; mso-list: l2 level1 lfo2; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(i)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span>To provide user interface</div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l2 level1 lfo2; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(ii)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span>To accept input from input
devices</div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l2 level1 lfo2; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(iii)<span style="font: 7.0pt "Times New Roman";">              
</span></span></span><span dir="LTR"></span>To send output to output
devices</div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l2 level1 lfo2; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(iv)<span style="font: 7.0pt "Times New Roman";">             
</span></span></span><span dir="LTR"></span>To manage the<span style="mso-spacerun: yes;">  </span>application programs in memory</div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l2 level1 lfo2; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(v)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span>To organize data on the
storage devices</div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l2 level1 lfo2; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(vi)<span style="font: 7.0pt "Times New Roman";">             
</span></span></span><span dir="LTR"></span>To perform memory management
tasks</div>
<div class="MsoListParagraphCxSpLast" style="margin-left: .75in; mso-add-space: auto; mso-list: l2 level1 lfo2; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(vii)<span style="font: 7.0pt "Times New Roman";">            
</span></span></span><span dir="LTR"></span>To manage and control the
I/O devices</div>
<div align="center" class="MsoNormal" style="margin-left: .25in; text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Functions of Operating system</span></b></div>
<div class="MsoNormal" style="margin-left: .25in;">
The operating system can perform
different kind of operations. Some of these functions are as follow:</div>
<div class="MsoNormal" style="margin-left: .25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Manage hardware resources:</span></b></div>
<div class="MsoNormal" style="margin-left: .25in;">
<span style="mso-tab-count: 4;">                                                        </span>The
operating system is used to manage the hardware resources. It has different
hardware resources like input/output devices, CPU and disks etc. </div>
<div class="MsoNormal" style="margin-left: .25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Memory management:</span></b></div>
<div class="MsoNormal" style="margin-left: .25in;">
<span style="mso-tab-count: 4;">                                                        </span>The
main memory plays a<span style="mso-spacerun: yes;">  </span>very important in
data processing. The data and instructions must be loaded into memory for
execution. Different kind of the instructions are loaded for execution at the
same time. The operating system manage these instructions and allocate to the
memory.</div>
<div class="MsoNormal" style="margin-left: .25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Load and execute programs:</span></b></div>
<div class="MsoNormal" style="margin-left: .25in;">
<span style="mso-tab-count: 4;">                                                        </span>A
program must be loaded into memory for execution. The operating system to do
work to perform these operations.</div>
<div class="MsoNormal" style="margin-left: .25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Data security:</span></b></div>
<div class="MsoNormal" style="margin-left: .25in;">
<span style="mso-tab-count: 2;">                        </span>Data
security is very important to protect our data. An operating system provide us
security facilities. </div>
<div class="MsoNormal" style="margin-left: .25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 16.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: "Times New Roman"; mso-fareast-font-family: Calibri; mso-hansi-font-family: Calibri;">Provide interface to the users:</span></b></div>
<div class="MsoNormal" style="margin-left: .25in;">
<span style="mso-tab-count: 4;">                                                        </span><span style="mso-spacerun: yes;"> </span>Operating system provide us the interface to
the user. User interface means how the user interact with the computer system
to perform different operations. The operating system provide to types of
interface;</div>
<div class="MsoListParagraphCxSpFirst" style="margin-left: .75in; mso-add-space: auto; mso-list: l0 level1 lfo3; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(i)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span>Command prompt</div>
<div class="MsoListParagraphCxSpLast" style="margin-left: .75in; mso-add-space: auto; mso-list: l0 level1 lfo3; text-indent: -.5in;">
<span style="mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">(ii)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span>Graphical user
interface(GUI)</div>

Instruction set and its types

Here I will discuss about the execution of the instructions of the computer system Instruction set A set of all instruction that a computer execute at one time is called instruction …

17 Feb 2016

Network Security (Vulnerability, Threats, Attacks)

<h2>
Network Security: </h2>
<h2>
                         <b style="-webkit-text-stroke-width: 0px; background-color: white; color: #222222; font-family: arial, sans-serif; font-size: 16px; font-style: normal; font-variant: normal; letter-spacing: normal; line-height: 19.2px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;">Network security</b><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #222222; display: inline !important; float: none; font-family: arial, sans-serif; font-size: 16px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.2px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;"><span class="Apple-converted-space"> </span>is protection of the access to files and directories in a <u><i>computer<span class="Apple-converted-space"> </span></i></u></span><u><i><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #222222; font-family: arial, sans-serif; font-size: 16px; font-style: normal; font-variant: normal; letter-spacing: normal; line-height: 19.2px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;">network</span></i></u><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #222222; display: inline !important; float: none; font-family: arial, sans-serif; font-size: 16px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.2px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;"><span class="Apple-converted-space"> </span>against hacking, misuse and unauthorized changes to the system. An example of<span class="Apple-converted-space"> </span></span><b style="-webkit-text-stroke-width: 0px; background-color: white; color: #222222; font-family: arial, sans-serif; font-size: 16px; font-style: normal; font-variant: normal; letter-spacing: normal; line-height: 19.2px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;">network security</b><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #222222; display: inline !important; float: none; font-family: arial, sans-serif; font-size: 16px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.2px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;"><span class="Apple-converted-space"> </span>is an anti virus system. Now a days Security is the first priority in any services. </span></h2>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghNMAk-WDgCbiAmkMfNxxYlQwRkua_MIjYlPP-sg3fA8WMonY0S7l9avtcms0mdz42bHnHz2CB4YqX10abgKFO-3V4we5PbgtbJJoo1ojNG3pi9wt5tFXvKz_8oyYnNXtuijl6QNtHzv0/s1600/netwrok-security-banner.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Network Security" border="0" height="101" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghNMAk-WDgCbiAmkMfNxxYlQwRkua_MIjYlPP-sg3fA8WMonY0S7l9avtcms0mdz42bHnHz2CB4YqX10abgKFO-3V4we5PbgtbJJoo1ojNG3pi9wt5tFXvKz_8oyYnNXtuijl6QNtHzv0/s400/netwrok-security-banner.jpg" title="Network Security" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Network Security</td></tr>
</tbody></table>
<h2>
<span style="-webkit-text-stroke-width: 0px; background-color: white; color: #222222; display: inline !important; float: none; font-family: arial, sans-serif; font-size: 16px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19.2px; orphans: auto; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;"> </span></h2>

<br />
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%;">Introduction to Vulnerabilities,
Threats, and Attacks</span></b></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<u><b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Vulnerability</span></b></u><span style="font-size: 12.0pt; line-height: 107%;">—A weakness that is inherent in every<i>
network</i> and device. This includes routers, switches, desktops, servers, and
even security devices themselves. </span></div>
<div class="MsoNormal">
<u><b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Threats</span></b></u><span style="font-size: 12.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: Calibri; mso-hansi-font-family: Calibri;">—</span><span style="font-size: 12.0pt; line-height: 107%;">the people eager, willing, and
qualified to take advantage of each security weakness, and they continually
search for new exploits and weaknesses. </span><span style="font-family: "arial" , sans-serif; font-size: 12.0pt; line-height: 107%;"></span></div>
<div class="MsoNormal">
<u><b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Attacks</span></b></u><span style="font-size: 12.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: Calibri; mso-hansi-font-family: Calibri;">—</span><span style="font-size: 12.0pt; line-height: 107%;">the threats use a variety of tools,
scripts, and programs to launch attacks against networks and network devices.
Typically, the network devices under attack are the endpoints, such as servers
and desktops.</span></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 18.0pt; line-height: 107%;">Vulnerabilities</span></b><span style="font-size: 18.0pt; line-height: 107%;">:</span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 107%;">Vulnerabilities
in network security can be summed up as the “soft spots” that are present in
every network. The vulnerabilities are present in the network and individual
devices that make up the network.</span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 107%;">Networks are
typically plagued by one or all of three primary vulnerabilities or weaknesses:</span></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l8 level1 lfo6; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Technology
weaknesses </span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l8 level1 lfo6; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Configuration
weaknesses </span></div>
<div class="MsoListParagraphCxSpLast" style="mso-list: l8 level1 lfo6; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Security policy
weaknesses</span></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l9 level1 lfo1; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-font-size: 12.0pt; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">a)<span style="font: 7.0pt "Times New Roman";">    
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Technological
Weaknesses</span></b><span style="font-size: 12.0pt; line-height: 107%;">: Computer
and network technologies have intrinsic security weaknesses. These include
TCP/IP protocol weaknesses, operating system weaknesses, and network equipment
weaknesses.</span></div>
<div class="MsoListParagraphCxSpMiddle">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Weakness </span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 123.75pt; mso-add-space: auto; mso-list: l10 level1 lfo2; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">I)<span style="font: 7.0pt "Times New Roman";">                   
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">TCP/IP protocol weaknesses</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 123.75pt; mso-add-space: auto;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                               </span><span style="mso-spacerun: yes;">       </span><span style="mso-spacerun: yes;">   </span>(HTTP, FTP, and ICMP are inherently insecure)</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 123.75pt; mso-add-space: auto; mso-list: l10 level1 lfo2; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">II)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Operating system weaknesses</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 123.75pt; mso-add-space: auto;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">        </span><span style="mso-spacerun: yes;">                                </span>(The UNIX,
Linux, Macintosh, Windows NT, 9x, 2K, XP, and OS/2 operating systems all have
security problems that must be addressed.)</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 123.75pt; mso-add-space: auto; mso-list: l10 level1 lfo2; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">III)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Network equipment weaknesses</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 123.75pt; mso-add-space: auto;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                                        </span>(Password
protection, Lack of authentication,</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 123.75pt; mso-add-space: auto;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;"> </span>Routing protocols, Firewall holes.)</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l9 level1 lfo1; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-font-size: 12.0pt; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">b)<span style="font: 7.0pt "Times New Roman";">   
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Configuration
Weaknesses: </span></b><span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;"> </span>Network administrators or network engineers
need to learn what the configuration weaknesses are and correctly configure
their computing and network devices to compensate.</span></div>
<div class="MsoListParagraphCxSpMiddle">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Weakness</span></b><span style="font-size: 12.0pt; line-height: 107%;"></span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l4 level1 lfo3; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">i)<span style="font: 7.0pt "Times New Roman";">                   
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Unsecured user account</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l4 level1 lfo3; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">ii)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">System accounts with easily guessed password</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l4 level1 lfo3; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">iii)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Misconfigured Internet service</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l4 level1 lfo3; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">iv)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Unsecured default settings within products</span></div>
<div class="MsoListParagraphCxSpLast" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l4 level1 lfo3; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">v)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Misconfigured network equipment</span></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l9 level1 lfo1; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-font-size: 12.0pt; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">c)<span style="font: 7.0pt "Times New Roman";">    
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Security Policy
Weaknesses: </span></b><span style="font-size: 12.0pt; line-height: 107%;">Security
policy weaknesses can create unforeseen security threats. The network can pose
security risks to the network if users do not follow the security policy</span></div>
<div class="MsoListParagraphCxSpMiddle">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Weakness</span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l7 level1 lfo4; text-align: justify; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">i)<span style="font: 7.0pt "Times New Roman";">                   
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Lack of written security policy</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l7 level1 lfo4; text-align: justify; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">ii)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Politic</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l7 level1 lfo4; text-align: justify; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">iii)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Lack of continuity</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l7 level1 lfo4; text-align: justify; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">iv)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Logical access controls not applied</span></div>
<div class="MsoListParagraphCxSpLast" style="margin-left: 120.75pt; mso-add-space: auto; mso-list: l7 level1 lfo4; text-align: justify; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">v)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Software and hardware installation of installation and
changes do not follow policy.</span><br />
<div class="separator" style="clear: both; text-align: center;">
<span style="font-size: 12.0pt; line-height: 107%;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaJYZSgznLBEoEKP1T1BfM_k_sptKlnSij-cHEtIyC7_Bh0IhWJR0FnQ7XXaoqAVisBKtaiX_IiDDk5kQT5XsDQcAtDFFFKLrXGNruPhACzi6Snsj71K_fjibnSEZQBHNycmuTFr8MYQE/s1600/SAS-IT-NETWORK-SECURITY-BANNER.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaJYZSgznLBEoEKP1T1BfM_k_sptKlnSij-cHEtIyC7_Bh0IhWJR0FnQ7XXaoqAVisBKtaiX_IiDDk5kQT5XsDQcAtDFFFKLrXGNruPhACzi6Snsj71K_fjibnSEZQBHNycmuTFr8MYQE/s640/SAS-IT-NETWORK-SECURITY-BANNER.jpg" width="640" /></a></span></div>
</div>
<div class="MsoNormal">
<br /></div>
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<br /></div>
<div align="center" class="MsoListParagraphCxSpLast" style="text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 22.0pt; line-height: 107%;">Threats</span></b></div>
<div class="MsoNormal" style="text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;">“A threat is an event that can take advantage of
vulnerability and cause a negative impact on the network.”</span></div>
<div class="MsoNormal" style="text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;">“A context of computer security, refers to anything that has
the potential to cause several harm to a computer system.”</span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 107%;">There are
the following type of Threat:</span></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l5 level1 lfo5; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Unstructured
threats</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l5 level1 lfo5; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Structured
threats</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l5 level1 lfo5; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">2External
threats</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l5 level1 lfo5; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Internal threats</span></div>
<div class="MsoListParagraphCxSpMiddle">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; mso-list: l3 level1 lfo7; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">a)<span style="font: 7.0pt "Times New Roman";">     
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Unstructured threats</span></b><b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">:<span style="mso-spacerun: yes;">  </span></span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;">Unstructured
threats consist of mostly inexperienced individuals using easily available
hacking tools such as shell scripts and password crackers. Even unstructured
threats that are only executed with the intent of testing and challenging a
hacker’s skills can still do serious damage to a company. For example, if an
external company website is hacked, the integrity of the company is damaged.
Even if the external website is separate from the internal information that
sits behind a protective firewall, the public does not know that.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; mso-list: l3 level1 lfo7; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">b)<span style="font: 7.0pt "Times New Roman";">   
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Structured threats:</span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                                   </span></span></b><span style="font-size: 12.0pt; line-height: 107%;">Structured threats come from hackers
who are more highly motivated and technically competent. These people know
system vulnerabilities and can understand and develop exploit code and scripts.
They understand, develop, and use sophisticated hacking techniques to penetrate
unsuspecting businesses. These groups are often involved with the major fraud
and theft cases reported to law enforcement agencies.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; mso-list: l3 level1 lfo7; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">c)<span style="font: 7.0pt "Times New Roman";">    
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">External threats:</span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                              </span><span style="mso-spacerun: yes;">      </span>External threats can arise from
individuals or organizations working outside of a company. They do not have
authorized access to the computer systems or network. They work their way into
a network mainly from the Internet or dialup access servers.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; mso-list: l3 level1 lfo7; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">d)<span style="font: 7.0pt "Times New Roman";">   
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Internal threats:</span></b></div>
<div align="center" class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; text-align: center;">
<span style="font-size: 12.0pt; line-height: 107%;">Internal threats occur when someone has authorized access to the network
with either an account on a server or physical access to the network. According
to the FBI, internal access and misuse account for 60 percent to 80 percent of
reported incidents.</span><span style="font-size: 22.0pt; line-height: 107%;"></span></div>
<div align="center" class="MsoListParagraphCxSpMiddle" style="margin-left: 39.0pt; mso-add-space: auto; text-align: center;">
<br /></div>
<div align="center" class="MsoListParagraphCxSpLast" style="margin-left: 39.0pt; mso-add-space: auto; text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 22.0pt; line-height: 107%;">Attacks</span></b></div>
<div class="MsoNormal" style="text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;">“An action taken against a target with the intention of doing
harm.”</span></div>
<div class="MsoNormal" style="text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;">Four primary classes of attacks exist:</span></div>
<div class="MsoListParagraphCxSpFirst" style="mso-list: l6 level1 lfo8; text-align: justify; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Reconnaissance</span><span style="font-family: "arial" , sans-serif; font-size: 12.0pt; line-height: 107%;"></span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l6 level1 lfo8; text-align: justify; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Access Attack</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l6 level1 lfo8; text-align: justify; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Denial of
service</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l6 level1 lfo8; text-align: justify; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Worms, viruses,
and Trojan horses</span></div>
<div class="MsoListParagraphCxSpMiddle" style="text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l0 level1 lfo9; text-align: justify; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">a)<span style="font: 7.0pt "Times New Roman";">    
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Reconnaissance:</span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                               </span></span></b><span style="font-size: 12.0pt; line-height: 107%;">Reconnaissance is the unauthorized
discovery and mapping of systems, services, or vulnerabilities (see Figure
1-13). It is also known as information gathering and, in most cases, it
precedes an actual access or denial-of-service (DoS) attack. Reconnaissance is
somewhat analogous to a thief casing a neighborhood for vulnerable homes to
break into, such as an unoccupied residence, easy-to-open doors, or open
windows.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l0 level1 lfo9; text-align: justify; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">b)<span style="font: 7.0pt "Times New Roman";">   
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Denial of Service
(DoS): </span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">           </span><span style="mso-spacerun: yes;">                                </span></span></b><span style="font-size: 12.0pt; line-height: 107%;">Denial of service implies that an
attacker disables or corrupts networks, systems, or services with the intent to
deny services to intended users. DoS attacks involve either crashing the system
or slowing it down to the point that it is unusable. But DoS can also be as
simple as deleting or corrupting information. In most cases, performing the
attack simply involves running a hack or script. The attacker does not need
prior access to the target because a way to access it is all that is usually
required. For these reasons, DoS attacks are the most feared.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l0 level1 lfo9; text-align: justify; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">c)<span style="font: 7.0pt "Times New Roman";">    
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Worms, Viruses, and
Trojan Horses:</span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                                                                 
</span></span></b><span style="font-size: 12.0pt; line-height: 107%;">Viruses are
malicious software that is attached to another program to execute a particular
unwanted function on a user’s workstation. An e example of example of a virus
is a program that is attached to command.com (the primary interpreter for
Windows systems) that deletes certain files and infects any other versions of
command.com that it can find.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;"><span style="mso-spacerun: yes;"> </span></span></b><span style="font-size: 12.0pt; line-height: 107%;">Malicious software is inserted onto a host to damage a
system; corrupt a system; replicate itself; or deny services or access to
networks, systems or services. They can also allow sensitive information to be
copied or echoed to other systems.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Trojan horses</span></b><span style="font-size: 12.0pt; line-height: 107%;"> can be used to ask the user to enter
sensitive information in a commonly trusted screen. For example, an attacker
might log in to a Windows box and run a program that looks like the true
Windows logon screen, prompting a user to type his username and password. The
program would then send the information to the attacker and then give the
Windows error for bad password. The user would then log out, and the correct
Windows logon screen would appear; the user is none the wiser that his password
has just been stolen.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; mso-list: l0 level1 lfo9; text-align: justify; text-indent: -.25in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">d)<span style="font: 7.0pt "Times New Roman";">   
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 14.0pt; line-height: 107%;">Access Attacks:</span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                                 </span><span style="mso-spacerun: yes;"> </span>Access attacks exploit known vulnerabilities
in authentication services, FTP services, and web services to gain entry to web
accounts, confidential databases, and other sensitive information. Access
attacks can consist of the following:</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: .75in; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l1 level1 lfo10; text-align: justify; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Password attacks</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l1 level1 lfo10; text-align: justify; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Man-in-the-middle
attacks</span></div>
<div class="MsoListParagraphCxSpMiddle" style="mso-list: l1 level1 lfo10; text-align: justify; text-indent: -.25in;">
<span style="font-family: "wingdings"; font-size: 12.0pt; line-height: 107%;"><span style="mso-list: Ignore;">§<span style="font: 7.0pt "Times New Roman";">  </span></span></span><span dir="LTR"></span><span style="font-size: 12.0pt; line-height: 107%;">Phishing</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; mso-list: l2 level1 lfo11; text-align: justify; text-indent: -.5in;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">i)<span style="font: 7.0pt "Times New Roman";">                   
</span></span></span></b><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Password Attacks: </span></b></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                                </span>Password
attacks can be implemented using several methods, including brute-force
attacks, Trojan horse programs, IP spoofing, and packet sniffers. Although
packet sniffers and IP spoofing can yield user accounts and passwords, password
attacks usually refer to repeated attempts to identify a user account,
password, or both (see Figure 1-17 for an illustration of an attempt to attack
using the administrator’s profile). These repeated attempts are called <b style="mso-bidi-font-weight: normal;">brute-force attacks.</b></span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;">The
following are the two methods for computing passwords: </span><span style="font-family: "arial" , sans-serif; font-size: 12.0pt; line-height: 107%;"></span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Dictionary cracking</span></b><span style="font-size: 12.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: Calibri; mso-hansi-font-family: Calibri;">—</span><span style="font-size: 12.0pt; line-height: 107%;">All of the words in a dictionary file
are computed and compared against the possible users’ password. This method is
extremely fast and finds simple passwords. </span><span style="font-family: "arial" , sans-serif; font-size: 12.0pt; line-height: 107%;"></span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;"> </span><b style="mso-bidi-font-weight: normal;">Brute-force
computation</b></span><span style="font-size: 12.0pt; line-height: 107%; mso-ascii-font-family: Calibri; mso-bidi-font-family: Calibri; mso-hansi-font-family: Calibri;">—</span><span style="font-size: 12.0pt; line-height: 107%;">This method
uses a particular character set, such as A to Z, or A to Z plus 0 to 9, and
computes the hash for every possible password made up of those characters. It
always computes the password if that password is made up of the character set
you have selected to test. The downside is that time is required for completion
of this type of attack. </span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; mso-list: l2 level1 lfo11; text-align: justify; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">ii)<span style="font: 7.0pt "Times New Roman";">                 
</span></span></span><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Man-in-the-Middle
Attacks</span></b><span style="font-size: 12.0pt; line-height: 107%;"> </span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                                                
</span>A man-in-the-middle attack requires that the hacker have access to
network packets that come across a network. An example could be someone who is
working for an Internet service provider (ISP) and has access to all network
packets transferred between the ISP network and any other network.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<span style="font-size: 12.0pt; line-height: 107%;">Such
attacks are often implemented using network packet sniffers and routing and
transport protocols. The possible uses of such attacks are theft of
information, hijacking of an ongoing session to gain access to private network
resources, traffic analysis to derive information about a network and its
users, denial of service, corruption of transmitted data, and introduction of
new information into network sessions.</span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<br /></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; mso-list: l2 level1 lfo11; text-align: justify; text-indent: -.5in;">
<span style="font-size: 12.0pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;">iii)<span style="font: 7.0pt "Times New Roman";">               
</span></span></span><span dir="LTR"></span><b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;">Phishing:</span></b><span style="font-size: 12.0pt; line-height: 107%;"></span></div>
<div class="MsoListParagraphCxSpMiddle" style="margin-left: 87.0pt; mso-add-space: auto; text-align: justify;">
<b style="mso-bidi-font-weight: normal;"><span style="font-size: 12.0pt; line-height: 107%;"><span style="mso-spacerun: yes;">                 </span></span></b><span style="font-size: 12.0pt; line-height: 107%;">Phishing is a type of social-engineering
attack that involves using e-mail or other types of messages in an attempt to
trick others into providing sensitive information, such as credit card numbers
or passwords. The phisher masquerades as a trusted party that has a seemingly
legitimate need for the sensitive information. Frequent phishing scams involve
sending out spam e-mails that appear to be from common online banking or
auction sites. These e-mails contain hyperlinks that appear to be legitimate
but actually cause users to visit a phony site set up by the phisher to capture
their information. The site appears to belong to the party that was faked in
the e-mail, and when users enter their information it is recorded for the
phisher to use.</span></div>
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Network Security (Vulnerability, Threats, Attacks)

Network Security: Network security is protection of the access to files and directories in a computer network against hacking, misuse and unauthorized changes to t…

11 Feb 2016

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