Which of the following is related to physical security and is not considered a technical control?
Correct Answer: D
Explanation/Reference: All of the above are considered technical controls except for locks, which are physical controls. Administrative, Technical, and Physical Security Controls Administrative security controls are primarily policies and procedures put into place to define and guide employee actions in dealing with the organization's sensitive information. For example, policy might dictate (and procedures indicate how) that human resources conduct background checks on employees with access to sensitive information. Requiring that information be classified and the process to classify and review information classifications is another example of an administrative control. The organization security awareness program is an administrative control used to make employees cognizant of their security roles and responsibilities. Note that administrative security controls in the form of a policy can be enforced or verified with technical or physical security controls. For instance, security policy may state that computers without antivirus software cannot connect to the network, but a technical control, such as network access control software, will check for antivirus software when a computer tries to attach to the network. Technical security controls (also called logical controls) are devices, processes, protocols, and other measures used to protect the C.I.A. of sensitive information. Examples include logical access systems, encryptions systems, antivirus systems, firewalls, and intrusion detection systems. Physical security controls are devices and means to control physical access to sensitive information and to protect the availability of the information. Examples are physical access systems (fences, mantraps, guards), physical intrusion detection systems (motion detector, alarm system), and physical protection systems (sprinklers, backup generator). Administrative and technical controls depend on proper physical security controls being in place. An administrative policy allowing only authorized employees access to the data center do little good without some kind of physical access control. From the GIAC.ORG website
Question 253
Why is traffic across a packet switched network difficult to monitor?
Correct Answer: C
With a packet switched network, packets are difficult to monitor because they can be transmitted using different paths. A packet-switched network is a digital communications network that groups all transmitted data, irrespective of content, type, or structure into suitably sized blocks, called packets. The network over which packets are transmitted is a shared network which routes each packet independently from all others and allocates transmission resources as needed. The principal goals of packet switching are to optimize utilization of available link capacity, minimize response times and increase the robustness of communication. When traversing network adapters, switches and other network nodes, packets are buffered and queued, resulting in variable delay and throughput, depending on the traffic load in the network. Most modern Wide Area Network (WAN) protocols, including TCP/IP, X.25, and Frame Relay, are based on packet-switching technologies. In contrast, normal telephone service is based on a circuit-switching technology, in which a dedicated line is allocated for transmission between two parties. Circuit-switching is ideal when data must be transmitted quickly and must arrive in the same order in which it's sent. This is the case with most real-time data, such as live audio and video. Packet switching is more efficient and robust for data that can withstand some delays in transmission, such as e-mail messages and Web pages. All of the other answer are wrong Reference(s) used for this question: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation. and https://en.wikipedia.org/wiki/Packet-switched_network and http://www.webopedia.com/TERM/P/packet_switching.html
Question 254
Which of the following concerning the Rijndael block cipher algorithm is false?
Correct Answer: C
Explanation/Reference: The answer above is the correct answer because it is FALSE. Rijndael does not support multiples of 64 bits but multiples of 32 bits in the range of 128 bits to 256 bits. Key length could be 128, 160, 192, 224, and 256. Both block length and key length can be extended very easily to multiples of 32 bits. For a total combination of 25 different block and key size that are possible. The Rijndael Cipher Rijndael is a block cipher, designed by Joan Daemen and Vincent Rijmen as a candidate algorithm for the Advanced Encryption Standard (AES) in the United States of America. The cipher has a variable block length and key length. Rijndael can be implemented very efficiently on a wide range of processors and in hardware. The design of Rijndael was strongly influenced by the design of the block cipher Square. The Advanced Encryption Standard (AES) The Advanced Encryption Standard (AES) keys are defined to be either 128, 192, or 256 bits in accordance with the requirements of the AES. The number of rounds, or iterations of the main algorithm, can vary from 10 to 14 within the Advanced Encryption Standard (AES) and is dependent on the block size and key length. 128 bits keys uses 10 rounds or encryptions, 192 bits keys uses 12 rounds of encryption, and 256 bits keys uses 14 rounds of encryption. The low number of rounds has been one of the main criticisms of Rijndael, but if this ever becomes a problem the number of rounds can easily be increased at little extra cost performance wise by increasing the block size and key length. Range of key and block lengths in Rijndael and AES Rijndael and AES differ only in the range of supported values for the block length and cipher key length. For Rijndael, the block length and the key length can be independently specified to any multiple of 32 bits, with a minimum of 128 bits, and a maximum of 256 bits. The support for block and key lengths 160 and 224 bits was introduced in Joan Daemen and Vincent Rijmen, AES submission document on Rijndael, Version 2, September 1999 available at http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf AES fixes the block length to 128 bits, and supports key lengths of 128, 192 or 256 bits only. Reference used for this question: The Rijndael Page and http://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf and FIPS PUB 197, Advanced Encryption Standard (AES), National Institute of Standards and Technology, U.S. Department of Commerce, November 2001.
Question 255
Which of the following algorithms is a stream cipher?
Correct Answer: B
Section: Cryptography Explanation/Reference: RC2, RC4, RC5 and RC6 were developed by Ronal Rivest from RSA Security. In the RC family only RC4 is a stream cipher. RC4 allows a variable key length. RC2 works with 64-bit blocks and variable key lengths, RC5 has variable block sizes, key length and number of processing rounds. RC6 was designed to fix a flaw in RC5. Source: ANDRESS, Mandy, Exam Cram CISSP, Coriolis, 2001, Chapter 6: Cryptography (page 103).
Question 256
Which backup method is additive because the time and tape space required for each night's backup grows during the week as it copies the day's changed files and the previous days' changed files up to the last full backup?
Correct Answer: A
Section: Risk, Response and Recovery Explanation/Reference: The Differential Backup Method is additive because the time and tape space required for each night's backup grows during the week as it copies the day's changed files and the previous days' changed files up to the last full backup. Archive Bits Unless you've done a lot of backups in your time you've probably never heard of an Archive Bit. An archive bit is, essentially, a tag that is attached to every file. In actuality, it is a binary digit that is set on or off in the file, but that's crummy technical jargon that doesn't really tell us anything. For the sake of our discussion, just think of it as the flag on a mail box. If the flag is up, it means the file has been changed. If it's down, then the file is unchanged. Archive bits let the backup software know what needs to be backed up. The differential and incremental backup types rely on the archive bit to direct them. Backup Types Full or Normal The "Full" or "normal" backup type is the most standard. This is the backup type that you would use if you wanted to backup every file in a given folder or drive. It backs up everything you direct it to regardless of what the archive bit says. It also resets all archive bits (puts the flags down). Most backup software, including the built-in Windows backup software, lets you select down to the individual file that you want backed up. You can also choose to backup things like the "system state". Incremental When you schedule an incremental backup, you are in essence instructing the software to only backup files that have been changed, or files that have their flag up. After the incremental backup of that file has occured, that flag will go back down. If you perform a normal backup on Monday, then an incremental backup on Wednesday, the only files that will be backed up are those that have changed since Monday. If on Thursday someone deletes a file by accident, in order to get it back you will have to restore the full backup from Monday, followed by the Incremental backup from Wednesday. Differential Differential backups are similar to incremental backups in that they only backup files with their archive bit, or flag, up. However, when a differential backup occurs it does not reset those archive bits which means, if the following day, another differential backup occurs, it will back up that file again regardless of whether that file has been changed or not. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 69. And: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, chapter 9: Disaster Recovery and Business continuity (pages 617-619). And: http://www.brighthub.com/computing/windows-platform/articles/24531.aspx
