Section: Network and Telecommunications
Explanation/Reference:
Any opening of an internal network to the Internet is susceptible of creating a new vulnerability.
Of the given rules, the one that permits all inbound tcp connections is the less likely to be used since it amounts to almost having no firewall at all, tcp being widely used on the Internet.
Reference(s) used for this question:
ALLEN, Julia H., The CERT Guide to System and Network Security Practices, Addison-Wesley, 2001, Appendix B, Practice-Level Policy Considerations (page 409).

When seeking to determine the security position of an organization, the security professional will eventually turn to a vulnerability assessment to help identify specific areas of weakness that need to be addressed. A vulnerability assessment is the use of various tools and analysis methodologies to determine where a particular system or process may be susceptible to attack or misuse. Most vulnerability assessments concentrate on technical vulnerabilities in systems or applications, but the assessment process is equally as effective when examining physical or administrative business processes.
The vulnerability assessment is often part of a BIA. It is similar to a Risk Assessment in that there is a quantitative (financial) section and a qualitative (operational) section. It differs in that i t is smaller than a full risk assessment and is focused on providing information that is used solely for the business continuity plan or disaster recovery plan.
A function of a vulnerability assessment is to conduct a loss impact analysis. Because there will be two parts to the assessment, a financial assessment and an operational assessment, it will be necessary to define loss criteria both quantitatively and qualitatively.
Quantitative loss criteria may be defined as follows: Incurring financial losses from loss of revenue, capital expenditure, or personal liability resolution The additional operational expenses incurred due to the disruptive event Incurring financial loss from resolution of violation of contract agreements Incurring financial loss from resolution of violation of regulatory or compliance requirements
Qualitative loss criteria may consist of the following:
The loss of competitive advantage or market share The loss of public confidence or credibility, or incurring public mbarrassment
During the vulnerability assessment, critical support areas must be defined in order to assess the impact of a disruptive event. A critical support area is defined as a business unit or function that must be present to sustain continuity of the business processes, maintain life safety, or avoid public relations embarrassment.
Critical support areas could include the following:
Telecommunications, data communications, or information technology areas Physical infrastructure or plant facilities, transportation services Accounting, payroll, transaction processing, customer service, purchasing
The granular elements of these critical support areas will also need to be identified. By granular elements we mean the personnel, resources, and services the critical support areas need to maintain business continuity
Reference(s) used for this question:
Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 4628-4632). Auerbach Publications. Kindle Edition.
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Page 277.

Section: Network and Telecommunications
Explanation/Reference:
A smurf attack occurs when an attacker sends a spoofed (IP spoofing) PING (ICMP ECHO) packet to the broadcast address of a large network (the bounce site). The modified packet containing the address of the target system, all devices on its local network respond with a ICMP REPLY to the target system, which is then saturated with those replies. An IP spoofing attack is used to convince a system that it is communication with a known entity that gives an intruder access. It involves modifying the source address of a packet for a trusted source's address. A teardrop attack consists of modifying the length and fragmentation offset fields in sequential IP packets so the target system becomes confused and crashes after it receives contradictory instructions on how the fragments are offset on these packets. A SYN attack is when an attacker floods a system with connection requests but does not respond when the target system replies to those requests.
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
76).

Explanation/Reference:
The Diffie-Hellman algorithm is used for Key agreement (key distribution) and cannot be used to encrypt and decrypt messages.
Source: WALLHOFF, John, CBK#5 Cryptography (CISSP Study Guide), April 2002 (page 4).
Note: key agreement, is different from key exchange, the functionality used by the other asymmetric algorithms.
References:
AIO, third edition Cryptography (Page 632)
AIO, fourth edition Cryptography (Page 709)

Explanation/Reference:
In cryptography, the one-time pad (OTP) is a type of encryption that is impossible to crack if used correctly.
Each bit or character from the plaintext is encrypted by a modular addition with a bit or character from a secret random key (or pad) of the same length as the plaintext, resulting in a ciphertext. If the key is truly random, at least as long as the plaintext, never reused in whole or part, and kept secret, the ciphertext will be impossible to decrypt or break without knowing the key. It has also been proven that any cipher with the perfect secrecy property must use keys with effectively the same requirements as OTP keys. However, practical problems have prevented one-time pads from being widely used.
First described by Frank Miller in 1882, the one-time pad was re-invented in 1917 and patented a couple of years later. It is derived from the Vernam cipher, named after Gilbert Vernam, one of its inventors.
Vernam's system was a cipher that combined a message with a key read from a punched tape. In its original form, Vernam's system was vulnerable because the key tape was a loop, which was reused whenever the loop made a full cycle. One-time use came a little later when Joseph Mauborgne recognized that if the key tape were totally random, cryptanalysis would be impossible.
The "pad" part of the name comes from early implementations where the key material was distributed as a pad of paper, so the top sheet could be easily torn off and destroyed after use. For easy concealment, the pad was sometimes reduced to such a small size that a powerful magnifying glass was required to use it.
Photos show captured KGB pads that fit in the palm of one's hand, or in a walnut shell. To increase security, one-time pads were sometimes printed onto sheets of highly flammable nitrocellulose so they could be quickly burned.
The following are incorrect answers:
A running key cipher uses articles in the physical world rather than an electronic algorithm. In classical cryptography, the running key cipher is a type of polyalphabetic substitution cipher in which a text, typically from a book, is used to provide a very long keystream. Usually, the book to be used would be agreed ahead of time, while the passage to use would be chosen randomly for each message and secretly indicated somewhere in the message.
The Running Key cipher has the same internal workings as the Vigenere cipher. The difference lies in how the key is chosen; the Vigenere cipher uses a short key that repeats, whereas the running key cipher uses a long key such as an excerpt from a book. This means the key does not repeat, making cryptanalysis more difficult. The cipher can still be broken though, as there are statistical patterns in both the key and the plaintext which can be exploited.
Steganography is a method where the very existence of the message is concealed. It is the art and science of encoding hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message. it is sometimes referred to as Hiding in Plain Sight.
Cipher block chaining is a DES operating mode. IBM invented the cipher-block chaining (CBC) mode of operation in 1976. In CBC mode, each block of plaintext is XORed with the previous ciphertext block before being encrypted. This way, each ciphertext block depends on all plaintext blocks processed up to that point. To make each message unique, an initialization vector must be used in the first block.
Reference(s) used for this question:
HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, chapter 8:
Cryptography (page 555).
and
http://en.wikipedia.org/wiki/One-time_pad
http://en.wikipedia.org/wiki/Running_key_cipher
http://en.wikipedia.org/wiki/Cipher_block_chaining#Cipher-block_chaining_.28CBC.29