- (Topic 4)
How is Annualized Loss Expectancy (ALE) derived from a threat?
Correct Answer:B
Three steps are undertaken in a quantitative risk assessment:
Initial management approval
Construction of a risk assessment team, and
The review of information currently available within the organization.
There are a few formulas that you MUST understand for the exam. See them below: SLE (Single Loss Expectancy)
Single loss expectancy (SLE) must be calculated to provide an estimate of loss. SLE is defined as the difference between the original value and the remaining value of an asset after a single exploit.
The formula for calculating SLE is as follows: SLE = asset value (in $) ?? exposure factor (loss due to successful threat exploit, as a %)
Losses can include lack of availability of data assets due to data loss, theft, alteration, or denial of service (perhaps due to business continuity or security issues).
ALE (Annualized Loss Expectancy)
Next, the organization would calculate the annualized rate of occurrence (ARO). This is done to provide an accurate calculation of annualized loss expectancy (ALE).
ARO is an estimate of how often a threat will be successful in exploiting a vulnerability over the period of a year.
When this is completed, the organization calculates the annualized loss expectancy (ALE). The ALE is a product of the yearly estimate for the exploit (ARO) and the loss in value of an asset after an SLE.
The calculation follows ALE = SLE x ARO
Note that this calculation can be adjusted for geographical distances using the local annual frequency estimate (LAFE) or the standard annual frequency estimate (SAFE). Given that there is now a value for SLE, it is possible to determine what the organization should spend, if anything, to apply a countermeasure for the risk in question.
Remember that no countermeasure should be greater in cost than the risk it mitigates, transfers, or avoids.
Countermeasure cost per year is easy and straightforward to calculate. It is simply the cost of the countermeasure divided by the years of its life (i.e., use within the organization). Finally, the organization is able to compare the cost of the risk versus the cost of the countermeasure and make some objective decisions regarding its countermeasure selection.
The following were incorrect answers: All of the other choices were incorrect.
The following reference(s) were used for this quesiton:
Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 10048-10069). Auerbach Publications. Kindle Edition.
- (Topic 3)
Which of the following usually provides reliable, real-time information without consuming network or host resources?
Correct Answer:A
A network-based IDS usually provides reliable, real-time information without consuming network or host resources.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the
Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 48.
- (Topic 5)
Which of the following is best at defeating frequency analysis?
Correct Answer:B
Simple substitution and transposition ciphers are vulnerable to attacks that perform frequency analysis.
In every language, there are words and patterns that are used more than others.
Some patterns common to a language can actually help attackers figure out the transformation between plaintext and ciphertext, which enables them to figure out the key that was used to perform the transformation. Polyalphabetic ciphers use different alphabets to defeat frequency analysis.
The ceasar cipher is a very simple substitution cipher that can be easily defeated and it does show repeating letters.
Out of list presented, it is the Polyalphabetic cipher that would provide the best protection against simple frequency analysis attacks.
Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw- Hill/Osborne, 2002, Chapter 8: Cryptography (page 507).
And : DUPUIS, Clement, CISSP Open Study Guide on domain 5, cryptography, April 1999.
- (Topic 4)
What can be defined as a momentary low voltage?
Correct Answer:B
A sag is a momentary low voltage. A spike is a momentary high voltage. A fault is a momentary power out and a brownout is a prolonged power supply that is below normal voltage.
Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw- Hill/Osborne, 2002, chapter 6: Physical security (page 299)
- (Topic 1)
Which of the following is the most reliable, secure means of removing data from magnetic storage media such as a magnetic tape, or a cassette?
Correct Answer:A
A "Degausser (Otherwise known as a Bulk Eraser) has the main function of reducing to near zero the magnetic flux stored in the magnetized medium. Flux density is measured in Gauss or Tesla. The operation is speedier than overwriting and done in one short operation. This is achieved by subjecting the subject in bulk to a series of fields of alternating polarity and gradually decreasing strength.
The following answers are incorrect:Parity Bit Manipulation. Parity has to do with disk lerror detection, not data removal. A bit or series of bits appended to a character or block of characters to ensure that the information received is the same as the infromation that was sent.
Zeroization. Zeroization involves overwrting data to sanitize it. It is time-consuming and not foolproof. The potential of restoration of data does exist with this method.
Buffer overflow. This is a detractor. Although many Operating Systems use a disk buffer to temporarily hold data read from disk, its primary purpose has no connection to data removal. An overflow goes outside the constraints defined for the buffer and is a method used by an attacker to attempt access to a system.
The following reference(s) were/was used to create this question: Shon Harris AIO v3. pg 908
Reference: What is degaussing.