- (Topic 5)
Which of the following statements pertaining to link encryption is false?
Correct Answer:
C
When using link encryption, packets have to be decrypted at each hop and encrypted again.
Information staying encrypted from one end of its journey to the other is a characteristic of end-to-end encryption, not link encryption.
Link Encryption vs. End-to-End Encryption
Link encryption encrypts the entire packet, including headers and trailers, and has to be decrypted at each hop.
End-to-end encryption does not encrypt the IP Protocol headers, and therefore does not need to be decrypted at each hop.
Reference: All in one, Page 735 & Glossary and
Source: WALLHOFF, John, CBK#5 Cryptography (CISSP Study Guide), April 2002 (page 6).
- (Topic 5)
Which of the following was developed in order to protect against fraud in electronic fund transfers (EFT) by ensuring the message comes from its claimed originator and that it has not been altered in transmission?
Correct Answer:
B
In order to protect against fraud in electronic fund transfers (EFT), the Message Authentication Code (MAC), ANSI X9.9, was developed. The MAC is a check value, which is derived from the contents of the message itself, that is sensitive to the bit changes in a message. It is similar to a Cyclic Redundancy Check (CRC).
The aim of message authentication in computer and communication systems is to verify that he message comes from its claimed originator and that it has not been altered in transmission. It is particularly needed for EFT Electronic Funds Transfer). The protection mechanism is generation of a Message Authentication Code (MAC), attached to the message, which can be recalculated by the receiver and will reveal any alteration in transit. One standard method is described in (ANSI, X9.9). Message authentication mechanisms an also be used to achieve non-repudiation of messages.
The Secure Electronic Transaction (SET) was developed by a consortium including MasterCard and VISA as a means of preventing fraud from occurring during electronic payment.
The Secure Hash Standard (SHS), NIST FIPS 180, available at http://www.itl.nist.gov/fipspubs/fip180-1.htm, specifies the Secure Hash Algorithm (SHA-1).
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 170)
also see:
http://luizfirmino.blogspot.com/2011/04/message-authentication-code-mac.html and
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.22.2312&rep=rep1&type=pdf
- (Topic 1)
What security model implies a central authority that define rules and sometimes global rules, dictating what subjects can have access to what objects?
Correct Answer:
D
As a security administrator you might configure user profiles so that users cannot change the system’s time, alter system configuration files, access a command prompt, or install unapproved applications. This type of access control is referred to as nondiscretionary, meaning that access decisions are not made at the discretion of the user. Nondiscretionary access controls are put into place by an authoritative entity (usually a security administrator) with the goal of protecting the organization’s most critical assets.
Non-discretionary access control is when a central authority determines what subjects can have access to what objects based on the organizational security policy. Centralized access control is not an existing security model.
Both, Rule Based Access Control (RuBAC or RBAC) and Role Based Access Controls (RBAC) falls into this category.
Reference(s) used for this question:
Harris, Shon (2012-10-18). CISSP All-in-One Exam Guide, 6th Edition (p. 221). McGraw- Hill. Kindle Edition.
and
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 33).
- (Topic 5)
Which of the following protocols that provide integrity and authentication for IPSec, can also provide non-repudiation in IPSec?
Correct Answer:
A
As per the RFC in reference, the Authentication Header (AH) protocol is a mechanism for providing strong integrity and authentication for IP datagrams. It might also provide non-repudiation, depending on which cryptographic algorithm is used and how keying is performed. For example, use of an asymmetric digital signature algorithm, such as RSA, could provide non-repudiation.
from a cryptography point of view, so we will cover it from a VPN point of view here. IPSec is a suite of protocols that was developed to specifically protect IP traffic. IPv4 does not have any integrated security, so IPSec was developed to bolt onto IP and secure the data the protocol transmits. Where PPTP and L2TP work at the data link layer, IPSec works at the network layer of the OSI model. The main protocols that make up the IPSec suite and their basic functionality are as follows: A. Authentication Header (AH) provides data integrity, data origin authentication, and protection from replay attacks. B. Encapsulating Security Payload (ESP) provides confidentiality, data-origin authentication, and data integrity. C. Internet Security Association and Key Management Protocol (ISAKMP) provides a framework for security association creation and key exchange. D. Internet Key Exchange (IKE) provides authenticated keying material for use with ISAKMP.
The following are incorrect answers:
ESP is a mechanism for providing integrity and confidentiality to IP datagrams. It may also provide authentication, depending on which lgorithm and algorithm mode are used. Non- repudiation and protection from traffic analysis are not provided by ESP (RFC 1827).
SSL is a secure protocol used for transmitting private information over the Internet. It works by using a public key to encrypt data that is transferred of the SSL connection. OIG 2007, page 976
SSH-2 is a secure, efficient, and portable version of SSH (Secure Shell) which is a secure replacement for telnet.
Reference(s) used for this question:
Shon Harris, CISSP All In One, 6th Edition , Page 705
and
RFC 1826, http://tools.ietf.org/html/rfc1826, paragraph 1.
- (Topic 1)
Which of the following would be used to implement Mandatory Access Control (MAC)?
Correct Answer:
C
The lattice is a mechanism use to implement Mandatory Access Control (MAC)
Under Mandatory Access Control (MAC) you have: Mandatory Access Control
Under Non Discretionary Access Control (NDAC) you have: Rule-Based Access Control
Role-Based Access Control
Under Discretionary Access Control (DAC) you have: Discretionary Access Control
The Lattice Based Access Control is a type of access control used to implement other access control method. A lattice is an ordered list of elements that has a least upper bound and a most lower bound. The lattice can be used for MAC, DAC, Integrity level, File Permission, and more
For example in the case of MAC, if we look at common government classifications, we have the following:
TOP SECRET
SECRET -----------------------I am the user at secret CONFIDENTIAL
SENSITIVE BUT UNCLASSIFIED UNCLASSIFIED
If you look at the diagram above where I am a user at SECRET it means that I can access document at lower classification but not document at TOP SECRET. The lattice is a list of ORDERED ELEMENT, in this case the ordered elements are classification levels. My least upper bound is SECRET and my most lower bound is UNCLASSIFIED.
However the lattice could also be used for Integrity Levels such as: VERY HIGH
HIGH
MEDIUM ----------I am a user, process, application at the medium level LOW
VERY LOW
In the case of of Integrity levels you have to think about TRUST. Of course if I take for example the the VISTA operating system which is based on Biba then Integrity Levels would be used. As a user having access to the system I cannot tell a process running with administrative privilege what to do. Else any users on the system could take control of the system by getting highly privilege process to do things on their behalf. So no read down would be allowed in this case and this is an example of the Biba model.
Last but not least the lattice could be use for file permissions: RWX
RW ---------User at this level
R
If I am a user with READ and WRITE (RW) access privilege then I cannot execute the file
because I do not have execute permission which is the X under linux and UNIX.
Many people confuse the Lattice Model and many books says MAC = LATTICE, however the lattice can be use for other purposes.
There is also Role Based Access Control (RBAC) that exists out there. It COULD be used to simulate MAC but it is not MAC as it does not make use of Label on objects indicating sensitivity and categories. MAC also require a clearance that dominates the object.
You can get more info about RBAC at:http://csrc.nist.gov/groups/SNS/rbac/faq.html#03 Also note that many book uses the same acronym for Role Based Access Control and Rule
Based Access Control which is RBAC, this can be confusing.
The proper way of writing the acronym for Rule Based Access Control is RuBAC, unfortunately it is not commonly used.
References:
There is a great article on technet that talks about the lattice in VISTA: http://blogs.technet.com/b/steriley/archive/2006/07/21/442870.aspx
also see:
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 33).
and
http://www.microsoft-watch.com/content/vista/gaging_vistas_integrity.html
