1 Information Security: The Big Picture - SANS GIAC © 2000 1 Information Security: The Big Picture – Part I Stephen Fried Hello, and welcome to Information Security: The Big Picture. My name is Stephen Fried, and over the course of the next six hours I will be guiding you on a tour of the world of information security. This course provides an introduction into the area of computer and network security. As more and more people and companies connect to the Internet, the incidence of hacker attacks, break-ins, and vandalism continues to increase. With this comes an increasing need for trained professionals to understand and combat this growing threat. This course will teach you the basics you need to begin securing your systems against threats from both inside and outside your organization. The course takes a high-level approach, touching on many different topics in an overview style. The information here is presented in plain English, not technical jargon, so students from all backgrounds can understand the material and begin to apply the concepts immediately. Technical concepts (e.g. communications technology, networking, protocols) are explained thoroughly in an easy-to- understand manner, allowing even non-technical students to understand these areas. We rely heavily on real-world examples and common-sense descriptions, enabling students to take their own “real world” experiences and apply them to the information security arena. So, without further ado, let’s get started. 2 Information Security: The Big Picture - SANS GIAC © 2000 2 Preface • Course is designed to give a broad introduction to information security • Use of real-world analogies to explain security concepts • Will not go into too much technical depth • Some technical descriptions may be oversimplified • Use of sample data – not “real” As stated before, this course is designed to give the student an introduction to the broad spectrum of topics that are covered under the umbrella of Information Security. To completely and thoroughly discuss all the possible topics that could be housed under that term would really take several weeks of in-depth study. Unfortunately, we only have six hours so we are going to take a more practical approach. We will touch on a variety of areas, giving explanations of each and diving into a few in more detail, but we will refrain from diving too deep into any one topic. As much as possible, I will try to use real-world examples to illustrate different terms and concepts. I have found, over the years, that many issues in information security are really the same ones that arise in our everyday lives. By applying those experiences to this new area, I hope to better explain the terms, concepts, and topics we will be discussing. This course does not go into a great deal of technical detail. It is designed for people who do not necessarily have a technical background but need to know more about security. We won’t be discussing much about bit patterns, dissecting the mathematical algorithms used in cryptography, and we’ll stay pretty clear of discussion or dissection of hardware and software. That is not to say that the course does not have technical content, it’s just that I’ve tried to limit it as much as possible. Which brings me to my next point. Some of the topics we cover are, in actuality, highly technical and to completely understand them does take a certain amount of technical explanation. So, in order to allow non- geek regular folks to understand and enjoy the topics I have had to simplify some of the more esoteric technical details and descriptions. My apologies in advance if my simplification goes a little far. Please know that it was all for the sake of reaching as wide an audience as possible. Finally, I use many examples of sample data in this course – Social Security numbers, network addresses, people and company names, etc. I have tried my best to make as much of this up as possible. Any resemblance between the example data and any persons, companies, or groups, living or dead, is purely coincidental. 3 Information Security: The Big Picture - SANS GIAC © 2000 3 Agenda • General Security Introduction • Telecommunications Fundamentals •Network Fundamentals •Network Security • World Wide Web Security • Information Secrecy & Privacy • Identification and Access Control • Programmatic Security •Conclusion Our first topic is a General Security Introduction. In this section we introduce you to some basic terms, concepts, and definitions you will need to begin understanding information security. 4 Information Security: The Big Picture - SANS GIAC © 2000 4 What Is “Security”? • “Freedom from risk or danger”* • The application of safeguards to prevent loss • A subjective measurement of preparedness for risk •A feeling of safety *The American Heritage Dictionary of the English Language I suppose the best way to start talking about information security is to examine the term “security” itself. What is “security?” I looked it up in my handy dictionary and found that the definition of Security is “freedom from risk or danger.” So, by extension, this would mean that information security would be the science of keeping information free from risk or danger. Well, that sounds good, and is certainly a worthy goal, but as we shall see over the span of this course, it is not a very realistic one. Why? Because in today’s world, particularly in today’s on-line world, you can never be completely free from risk or danger. There is just too much danger going around. So there will always be some risk. But that means we can never be secure… I guess I am talking in circles here, somewhat intentionally. Let’s start at the beginning. You can never be completely free from risk. When we get to the section on risk and risk analysis we will see how this is true. But for now, suffice to say that you can never completely prepare for all the bad things that will happen. So you have to pick and choose the dangers you want to protect against. You put your energy into preparing for those that you think are the most threatening and spend less time on those that you think are more remote. So here we see that security becomes subjective. If you have prepared against your own personal top ten threats, you feel secure. But, your top threats might be different than someone else’s top threats. Given your list of preparations, someone else might not feel as secure. There are no absolutes in security, no quick measurement to say definitively if you are secure or not. So you can never be sure that you have covered all the bases. But, if you do your homework, define your goals and threats, and make the proper preparations and install the proper safeguards, you will be more secure than if you had done nothing. And, in the end, maybe that’s what security is really all about – a feeling of safety. The notion that you feel better about your efforts to protect yourself and your assets. Perhaps we’ve started off a bit philosophically. Don’t worry, we’ll get back into the meat of things quickly, but I wanted to start you out with a feel of what security people face every day. Security is part art, part science, part technical, part philosophy, and all very interesting. 5 Information Security: The Big Picture - SANS GIAC © 2000 5 The Consequences of Inadequate Security • Loss of company assets • Loss of revenue/market share • Loss of intellectual property • Loss of privacy • Damage to reputation We will spend the rest of the course talking about the importance of security, risk and threats, and the steps you can take to improve the security of your organization. However, I believe the best way to start out the course is a brief discussion about the consequences of bad security. What would happen if you didn’t pay attention to security at all? Perhaps answering this question will get you in a frame of mind to think seriously about your security efforts. There are many consequences of bad security, and the list probably varies from organization to organization, but this slide shows the five major consequences. The first is loss of company assets. This the most obvious, as it deals with real, definable losses– damage to computers, loss of data, service disruptions on your network, etc. When most people think of security consequences they think of these types of issues. However, there are other consequences that can be just as damaging, but do not immediately come to mind. One of these is loss of revenue or market share. When an attacker comes in and defaces your web site, there will be time and expenses associated with repairing the damage. Those are the direct losses. However, the organization may also lose money because customers can’t get to the web site to order the company’s products or services. The longer the site takes to rebuild, the more potential revenue will be lost. Another indirect loss is market share. Depending on the type of business, a short-term loss is usually recoverable from a customer service perspective. Customers on the web today are used to short-term outages – annoyed, but used to it. However, if the outage lasts past a certain comfort level, customers will begin looking elsewhere for competing products. Ifthe outage is long enough, a serious loss of market share may be the result. An organization that does not pay proper attention to security can be risking its intellectual property. These represent the knowledge, experience, and research that the organization has developed, and can sometimes be so valuable to the organization that dollar figures can not even be placed on it. These are the types of assets that are most worthy of protection, since their loss might mean irreparable harm to the organization’s product development or financial outlook. A serious breach in security might mean the loss of privacy for your business or your customers. Privacy, particularly privacy of customer information, has become quite a hot topic over the past several years. We’ll discuss privacy issues in depth later in the course, but consumers and employees are coming to expect that their personal and financial information will be secured against unauthorized disclosure or theft. If an organization does not protect this information heavily and allows it to get in the handsof attackers, the loss to personal privacy may be irreparable. Finally, a great deal of e-commerce today is based on trust – trust in the vendor, trust in the vendor’s ability to perform as advertised, trust that information about yourself and your business will be kept confidential. A successful attack on your network or web site can cause that trust to be lost. Your organization’s reputation is based partly on the fact that it is perceived to be well run, treats business partners with respect, and that it takes the due care necessary to protect itself and its customers. As any businessperson knows, reputation can be as important as the balance sheet to a well-run business. Protecting your systems and networks helps to protect that reputation. 6 Information Security: The Big Picture - SANS GIAC © 2000 6 Basic Security Management Confidentiality Integrity Availability Information Security is generally said to rest on three fundamental pillars: Confidentiality, Integrity, and Availability. These three functions are commonly referred to as the C-I-A Triad. Confidentiality refers to the areas affecting the need to keep information private or secret and to prevent disclosure of information to those who do not need to see it. Confidentiality can be achieved through the use of encryption, by selective use of access controls, or by keeping sensitive information apart from publicly-available information. Integrity is the notion that information should be complete and unaltered as it is used and that any changes are made only by authorized people and properly recorded. Altering account balances in a financial system or modifying log records to hide a computer attack are examples of integrity attacks. Availability refers to the need to have information available for use when it is needed and in a form that is usable. Crashing a computer system or large-scale virus attacks are examples of availability attacks. These three elements - Confidentiality, Integrity, and Availability - are often interrelated. For instance, you can use encryption to handle both confidentiality and integrity issues. Alteration of a system’s information, generally considered an integrity issue, can also have availability consequences as well. Or, you may determine that for a particular environment or application, you need to pay less attention to one area or another. A web server that holds catalog or brochure information for a company may require high availability, but lower confidentiality, since the information is public anyway. Systems that handle bank wire transfers are usually concerned more with integrity than confidentiality or availability. However, in any review of overall security you will need to take all three of these issues into account. 7 Information Security: The Big Picture - SANS GIAC © 2000 7 How Secure is Secure Enough? (1) • Three fundamental questions –What are you protecting? –What is it worth to you? –What is it worth to someone else? Information security practitioners often wrestle with the problem of determining how much security is considered “enough” for a particular application. Unfortunately, there is no single correct answer to this question. The best place to start is by answering what I call the three fundamental questions about information security: First, what are you trying to protect? You need to define clearly what is the thing you have that is worth time and effort and energy to keep it safe from harm. Is it a web site? A business plan? A patented formula? An accounting system? You need to define as specifically as possible the object that needs protection, and without knowing this, you can go no further. Many security efforts go awry because they fail to answer this one basic question. Second, you need to determine what the object is worth to you. What is the intrinsic value this thing has that makes it worth protecting? It may be a monetary value. For instance, the amount of revenue an e-commerce site brings into your company. Or it may be more of a symbolic or subjective value. For instance, the amount your company’s reputation will suffer if its network gets hacked. In any case, you need to have a good idea of the value of the object, since that will lead you to determine how much effort you will put into protecting it. If the object is the cafeteria’s lunch menu for the week, you probably won’t put a lot of effort or money into protecting it. If, however, the object is the secret formula to your best-selling perfume, that is probably worth a lot more money to your company and worth putting extra resources into protecting it. Finally, how valuable the thing might be to someone else. If it is valuable to you, you can bet that there are others that will be willing to put effort into getting it as well. How much money could your top competitor make if they got hold of that secret formula? If word leaked out that your system for holding customer credit card numbers got attacked, would your customers move to your business rival? The value of your information to others may factor into how much you put into security. You need to address these three questions early on in your security planning. Until you have answered them to your satisfaction, do not go any further, because you will be putting money and resources into an ill- defined goal. 8 Information Security: The Big Picture - SANS GIAC © 2000 8 How Secure is Secure Enough? (2) • Dealing with motivations • Raising the effort bar • Making yourself less “attractive” • Security “lifetime” There are other factors to consider as well when determining how much security is “enough”. Conventional wisdom has it that you need to make security hard enough to break so that eventually an attacker will give up and go somewhere else. This is because it may become too expensive for an attacker to continue, or they may fear that additional time spent risks getting caught, or they may just get bored and go elsewhere. Much of this goes to the motivation of the attacker. Why are they trying to attack you? What do you have that they want? Unfortunately, the answer may not be so obvious. Sure, you may have something immediately identifiable like a product or money that they want. But you may be getting attacked because of who you are (like a government or a big, mean, oppressive multinational corporation). You may be getting attacked because of association with something you represent, like a particular industry (e.g. fur trading or a tobacco company). Or you may be attacked because your name popped into the head of the attacker as someone that might be “cool” to break into. The problem is that you may never know why you are getting hit. Without knowing the motivation, how do you determine how much security to apply? One of the best strategies is to raise the effort bar, so to speak. You need to apply enough security so that the level of effort required is greater than you think most attackers will be able to apply. You do this by applying the Defense in Depth strategy we will discuss shortly. Each layer of defense will hopefully serve to deter the attacker from going further in his attack so that eventually he will give up without getting to the “prize.” In this way, only the most determined, well funded, and experienced criminals will be able toget through all your defenses. You may never be able to completely secure your systems against all attacks, as that might be too expensive or resource intensive. But you can raise the effort level high enough for your own comfort. You can also make an effort to make yourself less “attractive” to a potential attacker. I know people in my neighborhood that put up “Beware of Dog” signs even if they don’t have a dog, or put burglar alarm company stickers in their windows even though they don’t have an alarm, or light up their house like a Christmas tree at night, all in an effort to deter burglars from trying to break into their house. You can apply the same concept with your systems and networks. Let people (both inside and outside your company) know you use a strong firewall system, or that you monitor and check all transactions that go through your web site, or that you actively prosecute attackers. These are the system equivalents of dog signs and flood lights. This may be enough to deter some would-be attackers from even attempting to break into your systems. Be careful, though. If you brag too much about your defenses you may actually encourage someone who wants to prove they are better than you. Finally, you want to make your security efforts commensurate with the useful lifetime of your information. For example, if you are trying to protect the revenue projections for your next quarter, you only really need to protect them until they are made public. Devising a system that will protect the secret for the next 50 years will not only be expensive, it may be overkill. 9 Information Security: The Big Picture - SANS GIAC © 2000 9 Who Are The Threats? • Hackers? •Vandals? •Espionage? • Insiders When looking at the possible sources that threaten your organization’s systems, you have to look at several types. The first group is the “hacker.” I use hacker in quotes because the real definition of hacker has changed so much over the years. By hacker I mean a person that uses computers and networks to inflict damage (either real or threatened) upon your environment. (Editor’s note: some people use the term ‘hacker’ simply to refer to someone who is interested in computers and in finding out how they work. This is in contrast with the work ‘cracker’, which refers to someone with malicious intent. – JEK) Hackers have certainly gotten a large amount of press in recent years and for good reason. But they are not necessarily your only threat, nor are they the biggest. Vandals are a sub-class of hackers. Whereas hackers may or may not be out to steal or disrupt your information, more often than not they will attempt to cover their tracks, at least initially. And, if they are really good, you may never know they have been in your systems. Vandals, on the other hand, are out to do visible damage to your systems. They will deface your web pages, erase your files, anything they can do to disrupt or damage your systems. You will know instantly when a vandal has been in your computer. Hackers and vandals present a real threat to your systems, but for the most part, they may not be out to get you directly. You are just a symbol or an object to them. However, practitioners of espionage are out to target you specifically. They will try to get your intellectual property, try to disrupt your operations or communications, and wreak havoc on your environment. They will be backed by your competitors or by a foreign government, and in some respects represent the most dangerous of all outside threats. They are generally well financed, well trained, and have a valuable goal in mind. Finally, one of the largest threats to any environment is insiders. Studies have repeatedly shown that insiders represent the largest cause of security incidents year after year. The reasons are obvious. These people are already in a position of trust, they know their way around the systems, and they know what security controls are in place and usually how they can be defeated. Whether it is through bribery, disgruntled employees, outsourced personnel, or someone with personal financial hardship, you need to be as mindful of the security impact of your insiders as you do of outsiders. 10 Information Security: The Big Picture - SANS GIAC © 2000 10 Who Do You “Trust?” • System will operate in ways that can be predicted • According to specifications • Only allow authorized activities • No undocumented features • Trust vs. Security Central to all discussions about information security is the concept of trust. In the real world, trust is an intangible concept that can be difficult to define but is readily understood. You trust someone based on your experiences with them, their reputation, your preferences, your ability to reach agreements with them, etc. These are all intangible properties, and there is no real way to measure trust . Computer and network security also uses the concept of trust and in many of the same ways. However, unlike real life, trust in the security sense has a precise definition and a set of measurable criteria. In order to have trust in a system, it must operate in ways that can be predicted, according to specifications, allowing only authorized activities, and can contain no undocumented information paths or features. Let’s look at each one of those criteria individually. The system will operate in ways that can be predicted. If you give input into a computer, given the same runtime environment, it should give you the exact same output every time. There should be no variation in the way the system operates. For example, if you install a building card access system, you need to know that every time a person holds their card up to the reader, the system will give an accurate response. If there is any variability in the system, if it sometimes allows unauthorized people in or prevents entry to authorized people, the system is of no use. The system must run according to specifications. This means that the system must have a formal specification of its operation and can not deviate from that specification. Like operating in predictable ways, operating according to specifications eliminates any random elements in the system’s operation. The system should only allow authorized activities. This means that every action taken by and within the system must be authorized by the system, and any users must be authorized both for access to the system itself as well as any activities they may perform while on the system. There must be no undocumented features in the system. One of the more common causes of security problems is the discovery of undocumented or hidden features. Once these features are discovered, they can be used to manipulate the system in unpredictable ways, thus violating the trust of the system. We should also make a distinction here between “trust” and “security”. As we have seen, trust refers to the dependability of a system to perform as expected within certain parameters. Security, on the other hand, is the sum total of issues relating to the confidentiality, integrity, and availability of systems and information. Trust is an important part of security, but it is only one part. [...]... dealing with risk is at the core of the information security professional’s job 18 Handling Risk • Eliminate risk • Minimize risk • Accept risk • Transfer risk Information Security: The Big Picture - SANS GIAC © 2000 19 There are several ways of dealing with risk First, you can eliminate the risk You do this by eliminating the cause of the risk or by decreasing your vulnerability to the risk For instance,... to drive? The cost of eliminating the risk is just too high So the second method of dealing with risk is to minimize the risk In our example we can minimize the risk of accidents in many ways We can drive slower and avoid crowded streets Or we can avoid driving at rush hour Many of these may impose some restrictions on our driving habits, but they are not as severe as eliminating driving all together... all over again 16 Security Awareness • The importance of awareness – Security stance – Dos and don’ts – Information protection – Assisting in the security effort • The benefits of effective awareness – Reduced security incidents – Improved knowledge amongst users – Reduction in losses Information Security: The Big Picture - SANS GIAC © 2000 17 Security awareness is the process through which you let... the street is in a suburban neighborhood you might feel there is less risk than if the street is in a big city If the street is in the middle of Disneyland you might not feel any risk at all The point is that risk is a subjective, variable feeling that can very often not be absolutely described or measured It is these subjective criteria that makes dealing with risk a particularly interesting matter... separate information by departments, or you might need to separate information into sensitivity levels In either case, you need to develop a mechanism for specifying how the information will be separated and who has access to which pieces of information This process is called Data Classification With data classification, each resource gets tagged with a sensitivity, usually high, medium, or low Then,... Managing Risk • Risk is all around us • Determining acceptable levels of risk • Tradeoffs – Comfort – Cost – Feasibility Information Security: The Big Picture - SANS GIAC © 2000 25 Managing risk is one of the fundamental tasks of an information security professional Without good risk management processes and techniques you will be forever running around fighting fires and playing catch-up with the bad... million variations but they all lead to one thing: people are usually willing to believe any information they are told and do not question its validity The only protection is to try to ensure the authenticity of the person you are talking with Don’t be afraid to have people authenticate themselves or to insist in checking before divulging sensitive information Be suspicious of stories that sound contrived... effort they are willing to go to to minimize or eliminate the risk Your comfort level or aversion to risk is also highly dependent on the situation and circumstances in which you find yourself For example, you might consider walking down a dark street to be a risk If you are a small child, you might think the risk is high If you are a policeman wearing a gun you might think the risk is reduced If the. .. know about them) Information Security: The Big Picture - SANS GIAC © 2000 21 The third element of the risk spectrum is the notion of Vulnerabilities In security terms, a vulnerability is a weakness in your systems or processes that allows a threat to occur However, simply having a vulnerability by itself is not a bad thing It is only when the vulnerability is coupled with a threat that the danger starts... Defense in Depth provides more security by making it harder for an attacker to get at anything valuable The harder it is, the more likely they will go elsewhere 11 Defense In Depth Network Host Application Info Information Security: The Big Picture - SANS GIAC © 2000 12 This diagram shows a pictorial representation of the Defense In Depth concept At the center of the diagram is your information However, the . Information Security: The Big Picture - SANS GIAC © 2000 1 Information Security: The Big Picture – Part I Stephen Fried Hello, and welcome to Information. reputation. 6 Information Security: The Big Picture - SANS GIAC © 2000 6 Basic Security Management Confidentiality Integrity Availability Information Security