Chapter 5 Exercises
1. If an organization must evaluate the following three information assets for risk management, which vulnerability should be evaluated first for additional safety controls? Which should be evaluated last?
· Switch L47 connects a network to the Internet. It has two vulnerabilities: it is susceptible to hardware failure at a likelihood of 0.2, and it is subject to an SNMP buffer overflow attack at a likelihood of 0.1. This switch has an impact rating of 90 and has no current controls in place. You are 75% certain of the assumptions and data.
· Server WebSrv6 hosts a company Web site and performs e-commerce transactions. It has a Web server version that can be attacked by sending it invalid Unicode values. The likelihood of that attack is estimated at 0.1. The server has been assigned an impact value of 100, and a control has been implanted that reduces the impact of vulnerability by 75%. You are 80% certain of the assumptions and data.
· Operators use an MGMT45 control console to monitor operations in the server room. It has no passwords and is susceptible to unlogged misuse by the operators. Estimates show the likelihood of the misuse is 0.1. There are no controls in place on this asset; it has an impact rating of 5. You are 90% certain of the assumptions and data.
a. First, I would calculate the risk of vulnerability by using the formula:
Rr = (Lv x I)(1 – Rc + U)
Switch L47 vulnerability 1 = (0.2 x 90)(1 – 0 + 0.25)
Switch L47 vulnerability 2 = (0.1 x 90)(1 – 0 + 0.25)
Server WebSrv6 vulnerability 3 = (0.1 x 100)(1 – 0.75 + 0.2)
MGMT45 control console vulnerability 4 = (0.1 x 5)(1 – 0 + 0.1)
Therefore, the vulnerability of Switch L47 would need to evaluated first because it has the highest risk rate (22.5) and the MGMT45 control console would be evaluated last because it has the lowest risk rate (0.55).
2. Using the data identification scheme in this chapter, identify and classify the information in your personal computer or personal digital assistant. Based on the potential for misuse or embarrassment, what information would be confidential, sensitive but unclassified, or for public release?
a. Confidential information would include my passwords, credit card information, social security number, or anything I don’t want other people to have access to. Information that would be sensitive but unclassified (internal) would be things that I allow close friends or family members to see such as usernames or banking documents. Information that would be for public release would be any information that I wouldn’t mind anyone knowing. For example, social media posts.
3. Suppose XYZ Software Company has a new application development project, with projected revenues of $1,200,000. Using the following table, calculate the ARO and ALE for each threat category that XYZ Software Company faces for this project.
a. ARO = Annualized Rate of Occurrence (expected frequency of an attack on a per-year basis). ALE = Annualized Loss Expectancy (calculated from ARO and SLE [single loss expectancy])
b. Formulas: ALE = SLE x ARO
(Answers are added on the chart below in the far right 3 columns in bold)
4. How might XYZ Software Company arrive at the values in the table shown in Exercise 3? For each entry, describe the process of determining the cost per incident and frequency of occurrence.
Programmer Mistakes- By using their salary, the value of possible damage, and the time it would take to fix the mistake. Also by using how many mistakes the programmer by make.
Loss of Intellectual Property- By estimating the overall value of the property that may be based on similar companies for the percentage lost each week. Then multiply by 52 to find the cost for the year.
Software Piracy- By finding out how much revenue could be lost each week based on the price of the software used, projected sales, and loss stats in other similar companies.
Theft of Information (Hacker)- By setting a value for possible information owned they find what % might be stolen within 3 months.
Theft of Information (Employee)- They double the stats of the above theft because an employee will probably wait before they attempt any type of theft against the company.
Web defacement- By finding a value on their Web page that is based on the cost of developing it, then finding the % of damage defacement would cost. Frequency of occurrence is based on other stats.
Theft of Equipment- Based on the fact that $5,000 worth of equipment is likely stolen from similar companies each year.
Viruses, worms, Trojan horses- Based on their network implementations and other known stats of exploitations and the time and money it would take to recover (paid to IT staff).
Denial-of-service attacks- Determine the amount of money lost if a server goes down. Average downtime multiplied by the # of employees multiplied by the average wage of each employee would be the cost of the damage.
Earthquake- Based on location.
Flood- Same as above.
Fire- Can be determined by looking up fire statistics.
5. Assume that a year has passed and XYZ has improved security by applying several controls. Using the information from Exercise 3 and the following table, calculate the post-control ARO and ALE for each threat category listed.
Why have some values changed in the Cost per Incident and Frequency of Occurrence columns?
-Because of the difference control methods that are used for each.
How could a control affect one but not the other?
Assume that the values in the Cost of Control column are unique costs directly associated with protecting against the threat. In other words, don’t consider overlapping costs between controls. Calculate the CBA for the planned risk controls approach in each threat category. For each threat category, determine whether the proposal control is worth the costs.
-Shown in chart above.