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System Security

Question No. 1

The computer security failure of Internal Revenue Service (IRS) causing from using weak password and inadequate control access to computer system and information is the most significant reported failure of computer security. The computer security failure occurred due to lack of control access to computer systems and information making the system vulnerable for the hackers. It is further reported that due to the issues such as easiest penetration, and weakest links, the data of the taxpayer has been at risk while failure to computer security is further caused by the weaknesses in program deficiencies (Mills, 2010). The lack of adequate computer security and failure to computer security caused the computing system data to be at the risk of the attackers and external hackers. Regarding the issue about security failure of computer, it is found that secrecy, integrity, availability and accountability are the major concerns. Computer security failure in such organization can lead to threats such as secrecy in a system is defined as data to be read by specific person, but computer security failure can make the secrecy vulnerable by letting the intruder to read the message or data. Integrity defined as a control on the changes and resources is the other concern in the computer security failure because computer security failure leads to access to unwanted users to get hold on the changes and control of the system while making the real users to lose integrity due to the intrusion. Availability in computer security failure refers to the provision of access to information and resources that must be accessed only by the authorized person. However, computer security failure leads to the threat to availability in which computer system can be accessed by an intruder or external hackers. Moreover, accountability is referred to knowing the individuals accessing the system while computer security failure leads to lack of information who is accessing the information and how the information is being used. Computer security that is explained as process of protecting the computing system against the threats can cause serious harms to computers, computing data, and other computing programs (Guttman& Roback, 1995). In the case of Internal Revenue Service (IRS) computer security failure, the computer systems were identified with major vulnerability including availability or easiest penetration, and correctness or inadequate protection. 

Question No. 2

The key identified for decrypting the message SELGBUAXOZKSUBOKOYHRGJKXATTKX is 20. To decrypt the text, letters were first converted into numbers and 20 was subtracted in each numbers of letter. Since the answer was gained in negative therefore, 26 will be added. The decrypted answer of the text is MYFAVOURITEMOVIEISBLADERUNNER.

Question No. 3

It has been noticed in observing the security of a system that as much as the secret encryption key and the encryption cipher stay on the use, the same gives more chances to the hackers and attackers to break down the rules of encryption. Therefore, in order to protect the system from such attacks, there is a need to buy thesis writing service. Cryptologists make recommendation time to time for changing the secret key and cipher for a creating a connection for a long period of time and for saving the system from the threats of the hackers. On the other hand, on considering the period for which a cryptographic key would be changed, it is observed that the default time set by the cryptologists for renegotiating the cryptographic keys is once in an hour (Assche, 2006). In addition to this, one could also set the time according to their requirements in minutes to renegotiate the keys using the switch frequency option in the system. Likewise, it could also be said that, cryptographic keys are required to be cancelled or changed as a method adopted to ensure the computer security of the system from the attackers.  Hence, the significant reason behind the recommendation made by the cryptographers for frequent changing of the cryptographic key is that the workload placed on the key by the process of encryption, that is going to be done by that key, keeps on reducing as more the load has been placed on that key (Pfleeger& Pfleeger, 2003). In other words, it could also be said that, the considerable volume of cipher text puts more pressure on the cryptographic key that has been used for decryption. Therefore, the cryptographers make an assumption that the attackers and hackers are analyzing all the transactions that are being performed by the key. This security element of the cryptographic keys, give rise to the need for the changing of the keys frequently. It has also been observed that the need for the change in cryptographic keys might be due to the need for stronger prevention against the cracking of the data.  Hence, it could be stated that with the emergence of new techniques to be used for the protection of computer security, there has been also an increase in the fundamental security problems attached with these new technologies.

Question No. 4

for the detection of the polymorphic viruses includes a generic decryption scanner to perform its task. This generic decryption scanner is itself comprised of several parts that include a CPU emulator, a module for controlling emulation (ECM) and a scanner to detect the signature of the virus. In addition to this, when a request is made by the user for the scanning of an executable file, the same suspected program is being loaded by the generic decryption into its software-stimulated system. After that, the program is permitted to be executed in this virtual system only just like that as if it has been executing in a real system. On the other hand, Finish poly has been considered as the first actual virus that tried to make confusion in the emulator using number of system calls, which is also offered by many coursework writing service providers. As it has been observed that many of the emulator do not assist the complete set of system calls that is accessible on a real computer system.  The virus did this by simply adding the system calls to confuse the element of the generic decryption technology that in turn results in the end of the emulation process (Ghonaim, El-Hadidi,& Aslan, 2002).

Question No. 5

Yes, a computer program can be used to automate the testing for trapdoors because trapdoors are the undocumented entry point to a module and testing for trapdoor can be carried out in integration that is done through automated option. It is because computing system is composed of complex structure, therefore, it is important to develop a methodical and organized system by testing the system components. Since the purpose of testing is to detect the bugging issues by taking advantage of the way system is composed, automated integration testing ensures that all components of the program system are functioning well together (Pfleeger'& Pfleeger, 2003).  Yes, a computer program can be designed using the source and object version of another program that has trapdoors and it is explained as the system with two modules namely MODA and MODB are tested using the driver MAIN and the stubs SORT, OUTPUT and NEWLINE. However, the automated system requires having only integration testing, conducting unit and integration testing, faults are recognized in the components. It could not be found what the source of problem was, debugging code was inserted in the suspicious module because debugging code makes it prominent to identify what is happening when components interact. In order to control the stubs debugging code, special control sequences in the design of components was embedded to support the testing. The component in the text formatting system can be designed to identify commands including .PAGE, .TITLE, and .SKIP. When testing the integration system, debugging code was invoked through command with series of parameters of the formvar= value. In order to explain the design with trapdoors, following is the coding: 

The above figure shows that modification is made using the value of internal program variables while executing the test correction to the components or to provide values passed to components. As it can be seen that command insertion is an identified testing practice, if left in place after testing, the additional commands might create problem. Moreover, they are undocumented control sequences, which generates side effects and it can be used as trapdoors. 

Question No. 6

Yes, there is a possibility that the File X could be leak by the subject A to the process C with help of process B. This might be because of the interconnection between the three processes mentioned in the shared resource matrix. The interconnectivity of the various processes within an organization, in turn give rise to the security issues related to the memory. As the process A is granted the authority to read the resource and due to the absence of virtual boundaries between two processes, one process could be easily transfer the resources that comes in its authorization to the another process that has been not granted authority.  

Question No. 7

From the security point of view, it is necessary to make maintenance of the field in the segment translation table as the table specifies the length of each segment. It has been assumed that the physical memory of the system is quite sufficient to hold the whole virtual address space in itself. The translation performed by MMU is 32- bit addresses from virtual memory that is converted in to the 32 bits of the physical memory. The data structure used for the purpose of translation is referred as the segment table (Pfleeger& Pfleeger, 2003). As the segment holds one entry for one virtual segment and this single entry itself is comprised of the three fields that includes physical addresses, length of the segment and the valid field. For protection of the different segments, the issues arise related to the size of the segment. Therefore, there is a need for the creation of the balanced protection accompanied with the efficient ways. Therefore, there is a need to understand the ways for making the segmentation as effective as possible (Lie, 2002). The segment translation table protects the security of the field of the table by maintaining the current length of the segments and by making comparison of the every address that has been generated. The security benefits attached with the segment translation table includes that each and every segment is being checked for the purpose of protection, different types of levels of protection could be assigned to the various types of data in the fields, this could allow an accessibility rights by allotting them totally different data. Moreover, on the other hand, a user could not be able to make generation of the address for those segments that are not permitted to the user. On the other hand, with the segment translation table, one could also make conversion of the different segment names into the numbers that are difficult to be recognized, which is very significant from the security point of view (Pfleeger& Pfleeger, 2003).

Question No. 8

A buffer overflow can be defined as the condition in which a program attempts to carry more data in a buffer than it can contain. In other words, buffer overflow occurs when program attempts to carry more data in a memory area past the buffer. When this occurs, a buffer becomes the sequential part of the memory that is allocated to carry anything from the character to string to an array of integers. Thus, when program writes outside the boundary of the block of the memory, it can corrupt the data, crash the program and can cause the execution of malicious codes.  The buffer overflow problem is the main issue in the network security emphasizing to realize how memory overflows and what impacts it has on the memory protection of the system. To deal with the buffer overflow issue, there are certain techniques used through memory data protection techniques such as fencing, relocating, bounding registers, segmentation, and paging. Through using the security or protection measures, protection measures can be taken by developing the protection in the hardware mechanism. When there is no fence developed for the protection of memory, there is possibility that buffer overflow occurs. However, fence is the simplest form of memory protection it is used in single-user operating system. In the relocating technique, if the size of the operating system is fixed then codes can be written starting at the constant address. Thus, the program of the operating system will identify the address of the object and will protect the memory of the system. Moreover, base or bounds registers can also be built in the operating system to protect the memory. It is mainly done when allocating the size or space required for specific program. Through fence registers, the programming can be relocated while with two or more than two users, none can know where the program is being loaded. 

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