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Answers to Exam Prep Questions
- C. A superscalar processor can execute multiple instructions at the same time. Answer A describes a scalar processor; it can execute only one instruction at a time. Answer B does not describe a superscalar processor because it does not have two large caches that are used as input and output buffers. Answer D is incorrect because a superscalar processor does not have two large caches that are used as output buffers.
- A. Back doors, also referred to as maintenance hooks, are used by programmers during development to give them easy access into a piece of software. Answer B is incorrect because a trap is a message used by the Simple Network Management Protocol (SNMP) to report a serious condition to a management station. Answer C is incorrect because a buffer overflow occurs because of poor programming. Answer D is incorrect because a covert channel is a means of moving information in a manner in which it was not intended.
- C. A covert channel is a means of moving information in a manner in which it was not intended. A buffer overflow occurs because of poor programming and usually results in program failure or the attacker’s ability to execute his code; thus, answer A is incorrect. An asynchronous attack deals with performing an operation between the TOC and the TOU (so answer B is incorrect), whereas a DoS attack affects availability not confidentiality (making answer D incorrect).
- D. The Complex Instruction Set Computing (CISC) CPU can perform multiple operations from a single instruction. Answer A is incorrect because DITSCAP is the Defense Information Technology Systems Certification and Accreditation Process. Answer B describes the Reduced Instruction Set Computing (RISC) CPU which uses simple instructions that require a reduced number of clock cycles. Answer C is incorrect because NIACAP is the National Information Assurance Certification and Accreditation Process, an accreditation process.
- C. ITSEC is a European standard that evaluates functionality and assurance separately. All other answers are incorrect because they do not separate the evaluation criteria. TCSEC is also known as the Orange Book, TNI is known as the Red Book, and CTCPEC is a Canadian assurance standard; therefore, answers A, B, and D are incorrect.
- A. Bell-LaPadula was the first model developed that is based on confidentiality. It uses two main rules to enforce its operation. Answers B, C, and D are incorrect. Biba and Clark-Wilson both deal with integrity, whereas the Take-Grant model is based on four basic operations.
- B. Clark-Wilson was developed for commercial activities. This model dictates that the separation of duties must be enforced, subjects must access data through an application, and auditing is required. Answers A, C, and D are incorrect. The Information Flow model addresses the flow of information and can be used to protect integrity or confidentiality. Bell-LaPadula is an integrity model and Brewer-Nash was developed to prevent conflict of interest.
- B. The Biba model assumes that internal threats are being protected by good coding practices and, therefore, focuses on external threats. Answers A, C, and D are incorrect. Biba addresses only integrity not availability or confidentiality.
- D. The Brewer-Nash model is also known as the Chinese Wall model and was specifically developed to prevent conflicts of interest. Answers A, B, and C are incorrect because they do not fit the description. Biba is integrity based, Take-Grant is based on four modes, and Harrison-Ruzzo-Ullman defines how access rights can be changed, created, or deleted.
- C. The Red Book examines integrity and availability of networked components. Answer A is incorrect because the Orange Book deals with confidentiality. Answer B is incorrect because the Brown Book is a guide to understanding trusted facility management. Answer D is incorrect because the Purple Book deals with database management.
- D. The *-property enforces “no write down” and is used to prevent someone with high clearance from writing data to a lower classification. Answers A, B, and C do not properly describe the Bell-LaPadula model star property.
- C. The purpose of the simple integrity property of the Biba model is to prevent someone to read an object of lower integrity. This helps protect the integrity of sensitive information.
- D. A guard is used to connect various MAC systems together and allow for communication between these systems. Answer A is incorrect because labels are associated with MAC systems but are not used to connect them together. Answer B is incorrect because the reference monitor is associated with the TCB. Answer C is incorrect because the term controls here is simply a distracter.
- A. Out of the four modes listed, only dedicated supports a valid need to know for all information on the system. Therefore, answers B, C, and D are incorrect.
- B. The Clark Wilson model was designed to support the goals of integrity and is focused on TLC, which stands for tampered, logged, and consistent. Answers A, C, and D are incorrect; Biba, Bell-LaPadula, and Brewer Nash are not associated with TLC.