Explanation/Reference:
Many times when a connection is opened, the firewall will inspect all layers of the packet. While this inspection is scaled back for subsequent packets to improve performance, this is the best of the four answers.
When packet filtering is used, a packet arrives at the firewall, and it runs through its ACLs to determine whether this packet should be allowed or denied. If the packet is allowed, it is passed on to the destination host, or to another network device, and the packet filtering device forgets about the packet. This is different from stateful inspection, which remembers and keeps track of what packets went where until each particular connection is closed. A stateful firewall is like a nosy neighbor who gets into people’s business and conversations. She keeps track of the suspicious cars that come into the neighborhood, who is out of town for the week, and the postman who stays a little too long at the neighbor lady’s house. This can be annoying until your house is burglarized. Then you and the police will want to talk to the nosy neighbor, because she knows everything going on in the neighborhood and would be the one most likely to know something unusual happened.
“Inspected at only one Open Systems Interconnetion (OSI) layer” is incorrect. To perform stateful packet inspection, the firewall must consider at least the network and transport layers.
“Decapsulated at all Open Systems Interconnection (OSI) layers” is incorrect. The headers are not stripped (“decapsulated” if there is such a word) and are passed through in their entirety IF the packet is passed.
“Encapsulated at all Open Systems Interconnect (OSI) layers” is incorrect. Encapsulation refers to the adding of a layer’s header/trailer to the information received from the above level. This is done when the packet is assembled not at the firewall.
Reference(s) used for this question:
CBK, p. 466
Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (pp. 632-633). McGraw-Hill. Kindle Edition.

Section: Risk, Response and Recovery
Explanation/Reference:
The Business Assessment is divided into two components. Risk Assessment (RA) and Business Impact Analysis (BIA). Risk Assessment is designed to evaluate existing exposures from the organization’s environment, whereas the BIA assesses potential loss that could be caused by a disaster. The Business Continuity Plan’s goal is to reduce the risk of financial loss by improving the ability to recover and restore operations efficiently and effectively.
Source: BARNES, James C. & ROTHSTEIN, Philip J., A Guide to Business Continuity Planning, John Wiley & Sons, 2001 (page 57).
And: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 8: Business Continuity Planning and Disaster Recovery Planning (page 276).

A trusted system is one that meets its intended security requirements. It involves sufficiency and effectiveness, not necessarily efficiency, in enforcing a security policy. Put succinctly, trusted systems have (1) policy, (2) mechanism, and (3) assurance. Source: HARE, Chris, Security Architecture and Models, Area 6 CISSP Open Study Guide, January 2002.

Access Control Techniques
Discretionary Access Control
Mandatory Access Control
Lattice Based Access Control
Rule-Based Access Control
Role-Based Access Control

Section: Risk, Response and Recovery
Explanation/Reference:
One of the key item to understand regarding backup is the archive bit. The archive bit is used to determine what files have been backuped already. The archive bit is set if a file is modified or a new file is created, this indicates to the backup program that it has to be saved on the next backup. When a full backup is performed the archive bit will be cleared indicating that the files were backup. This allows backup programs to do an incremental or differential backup that only backs up the changes to the filesystem since the last time the bit was cleared Full Backup (or Reference Backup) A Full backup will backup all the files and folders on the drive every time you run the full backup. The archive bit is cleared on all files indicating they were all backuped.
Advantages:
All files from the selected drives and folders are backed up to one backup set.
In the event you need to restore files, they are easily restored from the single backup set.
Disadvantages:
A full backup is more time consuming than other backup options.
Full backups require more disk, tape, or network drive space.
Incremental Backup
An incremental backup provides a backup of files that have changed or are new since the last incremental backup.
For the first incremental backup, all files in the file set are backed up (just as in a full backup). If you use the same file set to perform a incremental backup later, only the files that have changed are backed up. If you use the same file set for a third backup, only the files that have changed since the second backup are backed up, and so on.
Incremental backup will clear the archive bit.
Advantages:
Backup time is faster than full backups.
Incremental backups require less disk, tape, or network drive space.
You can keep several versions of the same files on different backup sets.
Disadvantages:
In order to restore all the files, you must have all of the incremental backups available.
It may take longer to restore a specific file since you must search more than one backup set to find the latest version of a file.
Differential Backup
A differential backup provides a backup of files that have changed since a full backup was performed. A differential backup typically saves only the files that are different or new since the last full backup. Together, a full backup and a differential backup include all the files on your computer, changed and unchanged.
Differential backup do not clear the archive bits.
Advantages:
Differential backups require even less disk, tape, or network drive space than incremental backups.
Backup time is faster than full or incremental backups.
Disadvantages:
Restoring all your files may take considerably longer since you may have to restore both the last differential and full backup.
Restoring an individual file may take longer since you have to locate the file on either the differential or full backup.
For more info see: http://support.microsoft.com/kb/136621
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 69.

Explanation/Reference:
Security awareness is a preventive measure, not a compensating measure for access violations.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 2: Access control systems (page 50).

TACACS+ is a proprietary Cisco enhancement to TACACS and is more robust than RADIUS. PAP is not a remote access authentication system but a remote node security protocol.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page 122).

Section: Security Operation Adimnistration
Explanation/Reference:
The Answer: security awareness training is to modify employees behaviour and attitude towards towards enterprise’s security posture.
Security-awareness training is performed to modify employees’ behavior and attitude toward security. This can best be achieved through a formalized process of security-awareness training.
It is used to increase the overall awareness of security throughout the company. It is targeted to every single employee and not only to one group of users.
Unfortunately you cannot apply a patch to a human being, the only thing you can do is to educate employees and make them more aware of security issues and threats. Never underestimate human stupidity.
Reference(s) used for this question:
TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.
also see:
Harris, Shon (2012-10-18). CISSP All-in-One Exam Guide, 6th Edition (p. 130). McGraw-Hill. Kindle Edition.

Explanation/Reference:
Conducting security awareness and technical training to ensure that end users and system users are aware of the rules of behaviour and their responsibilities in protecting the organization’s mission is an example of a preventive management control, therefore not an operational control.
Source: STONEBURNER, Gary et al., NIST Special publication 800-30, Risk management Guide for Information Technology Systems, 2001 (page 37).

Explanation/Reference:
Instead of using a Certificate Authority, PGP uses a “Web of Trust”, where users can certify each other in a mesh model, which is best applied to smaller groups.
In cryptography, a web of trust is a concept used in PGP, GnuPG, and other OpenPGP compatible systems to establish the authenticity of the binding between a public key and its owner. Its decentralized trust model is an alternative to the centralized trust model of a public key infrastructure (PKI), which relies exclusively on a certificate authority (or a hierarchy of such). The web of trust concept was first put forth by PGP creator Phil Zimmermann in 1992 in the manual for PGP version 2.0.
Pretty Good Privacy (PGP) is a data encryption and decryption computer program that provides cryptographic privacy and authentication for data communication. PGP is often used for signing, encrypting and decrypting texts, E-mails, files, directories and whole disk partitions to increase the security of e-mail communications. It was created by Phil Zimmermann in 1991.
As per Shon Harris’s book:
Pretty Good Privacy (PGP) was designed by Phil Zimmerman as a freeware e-mail security program and was released in 1991. It was the first widespread public key encryption program. PGP is a complete cryptosystem that uses cryptographic protection to protect e-mail and files. It can use RSA public key encryption for key management and use IDEA symmetric cipher for bulk encryption of data, although the user has the option of picking different types of algorithms for these functions. PGP can provide confidentiality by using the IDEA encryption algorithm, integrity by using the MD5 hashing algorithm, authentication by using the public key certificates, and nonrepudiation by using cryptographically signed messages. PGP initially used its own type of digital certificates rather than what is used in PKI, but they both have similar purposes. Today PGP support X.509 V3 digital certificates.
Reference(s) 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, Chapter 4: Cryptography (page 169).
Shon Harris, CISSP All in One book
https://en.wikipedia.org/wiki/Pretty_Good_Privacy
TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Its primary function is to send messages between network devices regarding the health of the network. ARP matches an IP address to an Ethernet address. RARP matches and Ethernet address to an IP address. ICMP runs on top of IP.

The 802.11 standard outlines how wireless clients and APs communicate, lays out the specifications of their interfaces, dictates how signal transmission should take place, and describes how authentication, association, and security should be implemeted.
The following answers are incorrect:
Public Key Infrastructure (PKI) Public Key Infrastructure is a supporting infrastructure to manage public keys. It is not part of the IEEE 802 Working Group standard.
Packet-switching technology A packet-switching technology is not included in the IEEE 802 Working Group standard. It is a technology where-in messages are broken up into packets, which then travel along different routes to the destination.
The OSI/ISO model The Open System Interconnect model is a sevel-layer model defined as an international standard describing network communications.
802.11 refers to a family of specifications developed by the IEEE for Wireless LAN technology.
802.11 specifies an over-the-air interface between a wireless client and a base station or between two wireless clients. The IEEE accepted the specification in 1997. There are several specifications in the 802.11 family:
802.11 # applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
802.11a # an extension to 802.11 that applies to wireless LANs and provides up to 54 Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or DSSS.
802.11b (also referred to as 802.11 High Rate or Wi-Fi) # an extension to 802.11 that applies to wireless LANS and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the
2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing wireless functionality comparable to Ethernet. 802.11g # applies to wireless LANs and provides 20+ Mbps in the 2.4 GHz band.

Physical controls are items put into place to protect facility, personnel, and resources. Examples of physical controls are security guards, locks, fencing, and lighting.
The following answers are incorrect answers:
Monitoring of system activity is considered to be administrative control.
Identification and authentication methods are considered to be a technical control.
Logical access control mechanisms is also considered to be a technical control.

Section: Network and Telecommunications
Explanation/Reference:
The TCP/IP protocol model is similar to the OSI model but it defines only four layers:
Application
Host-to-host
Internet
Network access
Reference(s) used for this question:
http://www.novell.com/documentation/nw65/ntwk_ipv4_nw/data/hozdx4oj.html and KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page 84).
also see:
http://en.wikipedia.org/wiki/Internet_Protocol_Suite#Layer_names_and_number_of_layers_in_the_literature

Explanation/Reference:
Infrared is generally considered to be more secure to eavesdropping than multidirectional radio transmissions because infrared requires direct line-of-sight paths.
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 173).

Data owners decide who has access to resources based only on the identity of the person accessing the resource.
The following answers are incorrect :
Mandatory Access Control : users and data owners do not have as much freedom to determine who can access files. The operating system makes the final decision and can override the users’ wishes and access decisions are based on security labels.
Sensitive Access Control : There is no such access control in the context of the above question.
Role-based Access Control : uses a centrally administered set of controls to determine how subjects and objects interact , also called as non discretionary access control.
In a mandatory access control (MAC) model, users and data owners do not have as much freedom to determine who can access files. The operating system makes the final decision and can override the users’ wishes. This model is much more structured and strict and is based on a security label system. Users are given a security clearance (secret, top secret, confidential, and so on), and data is classified in the same way. The clearance and classification data is stored in the security labels, which are bound to the specific subjects and objects. When the system makes a decision about fulfilling a request to access an object, it is based on the clearance of the subject, the classification of the object, and the security policy of the system. The rules for how subjects access objects are made by the security officer, configured by the administrator, enforced by the operating system, and supported by security technologies