無料提供されるSSCP問題集とSSCPリアル試験問題 [Q266-Q281]

Section: Access Control
Explanation/Reference:
In addition to the accuracy of the biometric systems, there are other factors that must also be considered.
These factors include the enrollment time, the throughput rate, and acceptability.
Enrollment time is the time it takes to initially “register” with a system by providing samples of the biometric characteristic to be evaluated. An acceptable enrollment time is around two minutes.
For example, in fingerprint systems, the actual fingerprint is stored and requires approximately 250kb per finger for a high quality image. This level of information is required for one-to-many searches in forensics applications on very large databases.
In finger-scan technology, a full fingerprint is not stored-the features extracted from this fingerprint are stored using a small template that requires approximately 500 to 1000 bytes of storage. The original fingerprint cannot be reconstructed from this template.
Updates of the enrollment information may be required because some biometric characteristics, such as voice and signature, may change with time.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 37 & 38.

The Data/Information Owner is ultimately responsible for the protection of the data. It is the Data/Information Owner that decides upon the classifications of that data they are responsible for.
The data owner decides upon the classification of the data he is responsible for and alters
that classification if the business need arises.
The following answers are incorrect:
Security Administrator. Is incorrect because this individual is responsible for ensuring that
the access right granted are correct and support the polices and directives that the
Data/Information Owner defines.
User. Is Incorrect because the user uses/access the data according to how the
Data/Information Owner defined their access.
Auditor. Is incorrect because the Auditor is responsible for ensuring that the access levels
are appropriate. The Auditor would verify that the Owner classified the data properly.
References:
CISSP All In One Third Edition, Shon Harris, Page 121

Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Explanation/Reference:
An investigator’s notebook cannot be used as evidence is court. It can only be used by the investigator to refresh his memory during a proceeding, but cannot be submitted as evidence in any form.
The following answers are incorrect:
When the investigator is unwilling to testify. Is incorrect because the notebook cannot be submitted as evidence in any form.
When other forms of physical evidence are not available. Is incorrect because the notebook cannot be submitted as evidence in any form.
If the defense has no objections. Is incorrect because the notebook cannot be submitted as evidence in any form.

As protocol was introduced by Visa and Mastercard to allow for more credit card transaction possibilities. It is comprised of three different pieces of software, running on the customer’s PC (an electronic wallet), on the merchant’s Web server and on the payment server of the merchant’s bank. The credit card information is sent by the customer to the merchant’s Web server, but it does not open it and instead digitally signs it and sends it to its bank’s payment server for processing.
The following answers are incorrect because :
SSH (Secure Shell) is incorrect as it functions as a type of tunneling mechanism that provides terminal like access to remote computers.
S/MIME is incorrect as it is a standard for encrypting and digitally signing electronic mail
and for providing secure data transmissions.
SSL is incorrect as it uses public key encryption and provides data encryption, server
authentication, message integrity, and optional client authentication.
Reference : Shon Harris AIO v3 , Chapter-8: Cryptography , Page : 667-669

The security of the RSA system is based on the assumption that factoring the product into two original large prime numbers is difficult
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 159). Shon Harris, CISSP All-in-One Examine Guide, Third Edition, McGraw-Hill Companies, August 2005, Chapter 8: Cryptography, Page 636 – 639

The Maximum Tolerable Downtime (MTD) is the maximum length of time a BUSINESS FUNCTION can endure without being restored, beyond which the BUSINESS is no longer viable
NIST SAYS: The ISCP Coordinator should analyze the supported mission/business processes and with the process owners, leadership and business managers determine the acceptable downtime if a given process or specific system data were disrupted or otherwise unavailable. Downtime can be identified in several ways.
Maximum Tolerable Downtime (MTD). The MTD represents the total amount of time the system owner/authorizing official is willing to accept for a mission/business process outage or disruption and includes all impact considerations. Determining MTD is important because it could leave contingency planners with imprecise direction on selection of an appropriate recovery method, and the depth of detail which will be required when developing recovery procedures, including their scope and content.
Other BCP and DRP terms you must be familiar with are:
Recovery Time Objective (RTO). RTO defines the maximum amount of time that a system resource can remain unavailable before there is an unacceptable impact on other system resources, supported mission/business processes, and the MTD. Determining the information system resource RTO is important for selecting appropriate technologies that are best suited for meeting the MTD. When it is not feasible to immediately meet the RTO and the MTD is inflexible, a Plan of Action and Milestone should be initiated to document the situation and plan for its mitigation.
Recovery Point Objective (RPO). The RPO represents the point in time, prior to a disruption or system outage, to which mission/business process data can be recovered (given the most recent backup copy of the data) after an outage. Unlike RTO, RPO is not considered as part of MTD. Rather, it is a factor of how much data loss the mission/business process can tolerate during the recovery process. Because the RTO must ensure that the MTD is not exceeded, the RTO must normally be shorter than the MTD. For example, a system outage may prevent a particular process from being completed, and because it takes time to reprocess the data, that additional processing time must be added to the RTO to stay within the time limit established by the MTD.
References used for this question:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Page 276. and http://csrc.nist.gov/publications/nistpubs/800-34-rev1/sp800-34-rev1_errata-Nov112010.pdf

Section: Security Operation Adimnistration
Explanation/Reference:
It is critical that a determination be made of WHAT data is important and should be retained and protected.
Without determining the data to be backed up, the potential for error increases. A record or file could be vital and yet not included in a backup routine. Alternatively, temporary or insignificant files could be included in a backup routine unnecessarily.
The following answers were incorrect:
When to make backups Although it is important to consider schedules for backups, this is done after the decisions are made of what should be included in the backup routine.
Where to keep backups The location of storing backup copies of data (Such as tapes, on-line backups, etc) should be made after determining what should be included in the backup routine and the method to store the backup.
How to store backups The backup methodology should be considered after determining what data should be included in the backup routine.

Section: Analysis and Monitoring
Explanation/Reference:
By reviewing system logs you can detect events that have occured.
The following answers are incorrect:
avoidance. This is incorrect, avoidance is a distractor. By reviewing system logs you have not avoided anything.
deterrence. This is incorrect because system logs are a history of past events. You cannot deter something that has already occurred.
prevention. This is incorrect because system logs are a history of past events. You cannot prevent something that has already occurred.

Block ciphers do not use public cryptography (private and public keys). Block ciphers is a type of symmetric-key encryption algorithm that transforms a fixed-size block of plaintext (unencrypted text) data into a block of ciphertext (encrypted text) data of the same length. They are appropriate for software implementations and can operate internally as a stream. See more info below about DES in Output Feedback Mode (OFB), which makes use internally of a stream cipher.
The output feedback (OFB) mode makes a block cipher into a synchronous stream cipher. It generates keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext. Just as with other stream ciphers, flipping a bit in the ciphertext produces a flipped bit in the plaintext at the same location. This property allows many error correcting codes to function normally even when applied before encryption.
Reference(s) used for this question:
Wikipedia on Block Cipher mode at: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation and http://www.itl.nist.gov/fipspubs/fip81.htm

Packet filtering is used in the first generation of firewalls and does not keep
track of the state of a connection. Stateful packet filtering does.
Source: WALLHOFF, John, CISSP Summary 2002, April 2002, CBK#2
Telecommunications and Network Security (page 6)

Explanation/Reference:
“Ultimately, people are the last line of defense for your company’s assets” (Pastore & Dulaney, 2006, p.
529).
Pastore, M. and Dulaney, E. (2006). CompTIA Security+ study guide: Exam SY0-101. Indianapolis, IN:
Sybex.

Explanation/Reference:
Only data to and from critical systems and applications should be allowed through the firewall is a detractor. Critical systems or applications do not necessarily need to have traffic go through a firewall.
Even if they did, only the minimum required services should be allowed. Systems that are not deemed critical may also need to have traffic go through the firewall.
Least privilege is a basic tenet of computer security that means users should be given only those rights required to do their jobs or tasks. Least privilege is ensuring that you have the minimum privileges necessary to do a task. An admin NOT using his admin account to check email is a clear example of this.
Reference(s) used for this question:
National Security Agency, Systems and Network Attack Center (SNAC), The 60 Minute Network Security Guide, February 2002, page 9.

Section: Cryptography
Explanation/Reference:
RFC 2828 (Internet Security Glossary) defines a digital signature as a value computed with a cryptographic algorithm and appended to a data object in such a way that any recipient of the data can use the signature to verify the data’s origin and integrity.
The steps to create a Digital Signature are very simple:
1. You create a Message Digest of the message you wish to send
2. You encrypt the message digest using your Private Key which is the action of Signing
3. You send the Message along with the Digital Signature to the recipient To validate the Digital Signature the recipient will make use of the sender Public Key. Here are the steps:
1. The receiver will decrypt the Digital Signature using the sender Publick Key producing a clear text message digest.
2. The receiver will produce his own message digest of the message received.
3. At this point the receiver will compare the two message digest (the one sent and the one produce by the receiver), if the two matches, it proves the authenticity of the message and it confirms that the message was not modified in transit validating the integrity as well. Digital Signatures provides for Authenticity and Integrity only. There is no confidentiality in place, if you wish to get confidentiality it would be needed for the sender to encrypt everything with the receiver public key as a last step before sending the message.
A Digital Envelope is a combination of encrypted data and its encryption key in an encrypted form that has been prepared for use of the recipient. In simple term it is a type of security that uses two layers of encryption to protect a message. First, the message itself is encoded using symmetric encryption, and then the key to decode the message is encrypted using public-key encryption. This technique overcomes one of the problems of public-key encryption, which is that it is slower than symmetric encryption. Because only the key is protected with public-key encryption, there is very little overhead.
A cryptographic hash is the result of a cryptographic hash function such as MD5, SHA-1, or SHA-2. A hash value also called a Message Digest is like a fingerprint of a message. It is used to proves integrity and ensure the message was not changed either in transit or in storage.
A Message Authentication Code (MAC) refers to an ANSI standard for a checksum that is computed with a keyed hash that is based on DES or it can also be produced without using DES by concataning the Secret Key at the end of the message (simply adding it at the end of the message) being sent and then producing a Message digest of the Message+Secret Key together. The MAC is then attached and sent along with the message but the Secret Key is NEVER sent in clear text over the network.
In cryptography, HMAC (Hash-based Message Authentication Code), is a specific construction for calculating a message authentication code (MAC) involving a cryptographic hash function in combination with a secret key.
As with any MAC, it may be used to simultaneously verify both the data integrity and the authenticity of a message. Any cryptographic hash function, such as MD5 or SHA-1, may be used in the calculation of an HMAC; the resulting MAC algorithm is termed HMAC-MD5 or HMAC-SHA1 accordingly. The cryptographic strength of the HMAC depends upon the cryptographic strength of the underlying hash function, the size of its hash output length in bits and on the size and quality of the cryptographic key.
There is more than one type of MAC: Meet CBC-MAC
In cryptography, a Cipher Block Chaining Message Authentication Code, abbreviated CBC-MAC, is a technique for constructing a message authentication code from a block cipher. The message is encrypted with some block cipher algorithm in CBC mode to create a chain of blocks such that each block depends on the proper encryption of the previous block. This interdependence ensures that a change to any of the plaintext bits will cause the final encrypted block to change in a way that cannot be predicted or counteracted without knowing the key to the block cipher.
References:
SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.
and
http://www.webopedia.com/TERM/D/digital_envelope.html
and
http://en.wikipedia.org/wiki/CBC-MAC

Section: Security Operation Adimnistration
Explanation/Reference:
This is an example of Separation of Duties because operators are prevented from modifying the system time which could lead to fraud. Tasks of this nature should be performed by they system administrators.
AIO defines Separation of Duties as a security principle that splits up a critical task among two or more individuals to ensure that one person cannot complete a risky task by himself.
The following answers are incorrect:
Programmers are permitted to use the system console. Is incorrect because programmers should not be permitted to use the system console, this task should be performed by operators. Allowing programmers access to the system console could allow fraud to occur so this is not an example of Separation of Duties..
Console operators are permitted to mount tapes and disks. Is incorrect because operators should be able to mount tapes and disks so this is not an example of Separation of Duties.
Tape operators are permitted to use the system console. Is incorrect because operators should be able to use the system console so this is not an example of Separation of Duties.
References:
OIG CBK Access Control (page 98 – 101)
AIOv3 Access Control (page 182)

Explanation/Reference:
Replay can be accomplished on Kerberos if the compromised tickets are used within an allotted time window.
The security depends on careful implementation:enforcing limited lifetimes for authentication credentials minimizes the threat of of replayed credentials, the KDC must be physically secured, and it should be hardened, not permitting any non-kerberos activities.
Reference:
Official ISC2 Guide to the CISSP, 2007 Edition, page 184
also see:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 42.