Security Risk Assessment

In this case study assignment, you will perform a quantitative risk analysis for a company’s network. Please use your imagination and feel free to specify any vulnerabilities and threats while completing the steps of this case study.

 

1. Download and read the Case Study: Information Security Risk Assessment Word document.
2. Download the Case Study Information Security Risk Assessment Answer Sheet.
3. Type all of your answers into the answer sheet.

Case Study: Information Security Risk Assessment

 

In this case study assignment, you will perform a quantitative risk analysis for the company network shown below. Write your answers on the Case Study Information Security Risk Assessment Answer Sheet.

 

 

Please use your imagination and feel free to specify any vulnerabilities and threats while completing the steps of this case study.

 

As depicted in the textbook, the following risk analysis formula will guide you throughout the process.

 

Risk = Probability (Threat + Exploit of Vulnerability) * Cost of Asset Damage

 

This formula tells that “Risk can be calculated by multiplying the probability (of exploitation of a vulnerability by a threat) with the impact (of the exploitation once occurred.)”

 

Rewrite the formula as follows:

 

Risk = Probability of the exploitation of a vulnerability by a threat * Impact of the exploitation

 

There are five steps of the risk analysis process.

 

• Specify three assets by using the network topology and the explanations.[1]
• For each of the assets, determine one vulnerability.[2]
• For each vulnerability, determine one threat that may exploit the vulnerability.[3]

 

Fill out the first three columns of Table-1.

 

Table-1
Assets	Vulnerabilities	Threats	Probability -numerical value	Impact-numerical value	Risk

 

Think about the threats and vulnerabilities for each asset. For each asset, appraise the probability of the exploitation of the vulnerability (in the second column) by the threat (in the third column). For this estimation, use the following reference table.  You should also think about the factors like “is the threat agent external or internal, what is the severity of the vulnerability, is it remotely exploitable?”

 

Probability	Numerical value	Frequency of exploitation
Very Low	1	Once per year
Low	2	Once every six months
Medium	3	Once per month
High	4	Once per week
Very High	5	Once per day

 

Write the numerical value to the fourth column of Table-1.

 

Write your justifications here:

Probability-numerical value	Your Justification (Why you assigned that value for the probability)

 

• Think about the assets. For each asset, appraise the impact once the asset is damaged. For this estimation, use the following reference table.

 

Impact	Numerical value	Impact of exploitation
Very Low	1	The systems/asset may be restored immediately.
Low	2	The systems/asset may be restored in the short term.
Medium	3	The systems/asset may be restored in the medium term.
High	4	The systems/asset may be restored in the long term.
Very High	5	The systems/asset may not restored in the long term, and the adverse effects may persist even longer.

 

Write the numerical value to the fifth column of Table-1.

 

Write your justifications here:

Impact-numerical value	Your Justification (Why you assigned that value for the impact)

 

• Multiply the values in the fourth and fifth columns in Table-1 and write the result to the sixth column.

 

Risk		Impact
		1	2	3	4	5
Probability	1	1	2	3	4	5
	2	2	4	6	8	10
	3	3	6	9	12	15
	4	4	8	12	16	20
	5	5	10	15	20	25

 

Risk Value	Priority
12, 15, 16, 20, 25	Highest priority
5, 6, 8, 9, 10	Medium priority
1, 2, 3, 4	Lowest priority

 

Fill out Table-2 from the highest-level risk to the lowest level. Also replace the <asset>, <vulnerability>, and <threat> by your findings. Write your action to the third column. If it has low probability, you may accept risk; otherwise, consider mitigating the risk, and write your mitigation actions.

 

Table-2
Definition of Risk	Priority	Action (Risk Acceptance or Risk Mitigation)
The exploitation of the <vulnerability> of <asset> by <threat>
The exploitation of the <vulnerability> of <asset> by <threat>
The exploitation of the <vulnerability> of <asset> by <threat>

 

Use “Case Study Information Security Risk Assessment Answer Sheet” document for your answers. 

[1] An asset is anything that has a value for the company. It can be software, hardware, storage media, documents, even employees. One of the most critical assets is information. Note that, one of the essential duties of the other assets (software, hardware, etc.) is to process information. Therefore, the value of a software, for example, is directly proportional to the value of information it processes.

[2] A vulnerability is a weakness in design, development, structure, properties or configurations of an asset. An asset’s weakness could allow it to be exploited and harmed by one or more threats.

[3] A threat is an active agent that has the intent and/or potential of exploiting vulnerabilities and causing harm. There are many threat agents that fall into broad categories of deliberate or accidental actions of human (internal or external to the organization) and acts of nature.

 

 

Case Study: Information Security Risk Assessment – Answer Sheet

 

 

Table-1
Assets	Vulnerabilities	Threats	Probability -numerical value	Impact-numerical value	Risk

 

 

Probability-numerical value	Your Justification (Why you assigned that value for the probability)

 

 

Impact-numerical value	Your Justification (Why you assigned that value for the impact)

 

 

Table-2
Definition of Risk	Priority	Action (Risk Acceptance or Risk Mitigation)
The exploitation of the <vulnerability> of <asset> by <threat>
The exploitation of the <vulnerability> of <asset> by <threat>
The exploitation of the <vulnerability> of <asset> by <threat>