If you’re planning to take the SY0-501 version of the Security+ exam, you should understand business impact analysis concepts. It helps an organization identify critical systems and components that are essential to the organization’s success.
For example, can you answer this Security+ question?
Q. Lisa is the new chief technology officer (CTO) at your organization. She wants to ensure that critical business systems are protected from isolated outages. Which of the following would let her know how often these systems will experience outages?
A. MTTR
B. MTBF
C. RTO
D. RPO
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation are available at the end of this post.
Impact
The business impact analysis (BIA) evaluates various scenarios, such as fires, attacks, power outages, data loss, hardware and software failures, and natural disasters. Additionally, the BIA attempts to identify the impact from these scenarios.
When evaluating the impact, a BIA looks at multiple items. For example, a database server might host customer data, including credit card information. If an attacker was able to access this customer data, the cost to the organization might exceed millions of dollars.
You might remember the attack on retail giant Target during November and December 2013. Attackers accessed customer data on more than 110 million customers, resulting in significant losses for Target. Estimates of the total cost of the incident have ranged from $600 million to over $1 billion. This includes loss of sales—Target suffered a 46 percent drop in profits during the last quarter of 2013, compared with the previous year. Customers were afraid to use their credit cards at Target and simply stayed away. It also includes the cost to repair their image, the cost of purchasing credit monitoring for affected customers, fines from the payment-card industry, and an untold number of lawsuits. Target reportedly has $100 million in cyber insurance that helped them pay claims related to the data breach.
Recovery Time Objective
The recovery time objective (RTO) identifies the maximum amount of time it can take to restore a system after an outage. Many BIAs identify the maximum acceptable outage or maximum tolerable outage time for mission-essential functions and critical systems. If an outage lasts longer than this maximum time, the impact is unacceptable to the organization.
For example, imagine an organization that sells products via a web site generates $10,000 in revenue an hour. It might decide that the maximum acceptable outage for the web server is five minutes. This results in an RTO of five minutes, indicating any outage must be limited to less than five minutes. This RTO of five minutes only applies to the mission-essential function of online sales and the critical systems supporting it.
Imagine that the organization has a database server only used by internal employees, not online sales. Although the database server may be valuable, it is not critical. Management might decide they can accept an outage for as long as 24 hours, resulting in an RTO of less than 24 hours.
Recovery Point Objective
A recovery point objective (RPO) identifies a point in time where data loss is acceptable. As an example, a server may host archived data that has very few changes on a weekly basis. Management might decide that some data loss is acceptable, but they always want to be able to recover data from at least the previous week. In this case, the RPO is one week.
With an RPO of one week, administrators would ensure that they have at least weekly backups. In the event of a failure, they will be able to restore recent backups and meet the RPO.
In some cases, the RPO is up to the minute of the failure. For example, any data loss from an online database recording customer transactions might be unacceptable. In this case, the organization can use a variety of techniques to ensure administrators can restore data up to the moment of failure.
Comparing MTBF and MTTR
When working with a BIA, experts often attempt to predict the possibility of a failure.
For example, what is the likelihood that a hard disk within a RAID configuration will fail? The following two terms are often used to predict potential failures:
• Mean time between failures (MTBF). The mean time between failures (MTBF) provides a measure of a system’s reliability and is usually represented in hours. More specifically, the MTBF identifies the average (the arithmetic mean) time between failures. Higher MTBF numbers indicate a higher reliability of a product or system. Administrators and security experts attempt to identify the MTBF for critical systems with a goal of predicting potential outages.
• Mean time to recover (MTTR). The mean time to recover (MTTR) identifies the average (the arithmetic mean) time it takes to restore a failed system. In some cases, people interpret MTTR as the mean time to repair, and both mean essentially the same thing. Organizations that have maintenance contracts often specify the MTTR as a part of the contract. The supplier agrees that it will, on average, restore a failed system within the MTTR time. The MTTR does not provide a guarantee that it will restore the system within the MTTR every time. Sometimes, it might take a little longer and sometimes it might be a little quicker, with the average defined by the MTTR.
Q. Lisa is the new chief technology officer (CTO) at your organization. She wants to ensure that critical business systems are protected from isolated outages. Which of the following would let her know how often these systems will experience outages?
A. MTTR
B. MTBF
C. RTO
D. RPO
Answer is B. The mean time between failures (MTBF) provides a measure of a system’s reliability and would provide an estimate of how often the systems will experience outages.
The mean time to recover (MTTR) refers to the time it takes to restore a system, not the time between failures.
The recovery time objective (RTO) identifies the maximum amount of time it can take to restore a system after an outage.
The recovery point objective (RPO) identifies a point in time where data loss is acceptable.
See Chapter 9 of the CompTIA Security+: Get Certified Get Ahead: SY0-501 Study Guide for more information on business continuity.