Risk Management with an Evolutionary Perspective

Evolutionary biology can provide useful insights into the risk management process that is used in information security. The current risk management process as described in NIST Special Publications 800-30, Risk Management Guide for Information Technology Systems and 800-39 Rev 1 (Draft), Managing Risk from Information Systems, could be summarized simply as: 1) identify the risks present in the environment, 2) counter/mitigate the risks that have been identified, and 3) repeat. This cycle is ultimately reactive in nature as flaws are only uncovered when vulnerabilities or new attacks are announced. SP 800-39 Rev 1 (Draft) is more focused on categorizing a system, and applying a set of requirements based on the system's categorization and security control customization based on tailoring. This methodology requires that the system's sensitivity rating has been appropriately determined and the predefined security controls appropriately address the threat environment.

If the assumption is made that information security is indeed a system which operating under the rules of a Red Queen hypothesis and that the security controls that are implemented are acting as selection pressures on our adversaries, the risk management process appears to be lacking as that there is nothing that takes into account how an adversary will respond to the environmental selection pressures (i.e. implemented security controls).

When a risk is identified, there are a number of ways that it can be handled within the current risk management framework. A risk can be corrected, accepted, mitigated, or transferred/insured. Each of these methods for dealing with an identified risk can be treated as one of the three types of selection pressures: directional, disruptive or stabilizing.

• Corrected risks can act as disruptive selection pressures. It is a disruptive selection pressure in the sense that the risk has been removed; an adversary must abandon the strategy that could be used to exploit the system. The adversary will be forced to evolve a new strategy if they are going to continue to exploit the system.
• Accepted risks can act as a stabilizing selection pressure. It is a stabilizing selection pressure in that it encourages an adversary to continue to use the existing exploitation strategy and discourages the use of other strategies in that they will cost resources to evolve and develop (which could be used elsewhere). Some would argue that an entity can also deny that a risk exists in the first place, if so then by default they are accepting the risk and treated it as an accepted risk.
• Mitigated risks can act as either a disruptive or directional selection pressure. If the mitigation causes an adversary to abandon their exploitation strategy it will be a disruptive selection pressure on the adversary. If the mitigation simply causes the adversary to modify their existing strategy it will act like a directional selection pressure.
• Transferred/Insured risks can act as a stabilizing selection pressure. Like accepted risks, transferred/insured risks will not exert a selection pressure on an adversary's strategy which causes them to either modify or abandon their existing strategy. If the risk is transferred or insured, it should be noted that it does not transfer the risk of an incident occurring. Just as when car insurance is purchased, the insurance company does not actually assume the risk of getting into an accident, the driver still carries that and the insurer carries the risk of having to payout out after an incident.

Each type of selection pressure exerts evolutionary costs in response. When multiple methods for dealing with a risk are identified, the evolutionary cost of the adversary to overcome the strategy should be considered in addition to the organization's cost for implementing (or not implementing as the case may be) a strategy. In general, disruptive selection pressures will exert the highest evolutionary cost on an adversary, while stabilizing selection pressures will tend to exert a minimal or non-existent evolutionary cost on an adversary.

• Disruptive selection pressures are the most likely method to extract the highest evolutionary cost from an adversary in that they will force them to not only evolve/develop a new exploitation strategy, but also waste the effort of continuing to maintain a strategy that may not succeed.
• Directional selection pressures will tend to exert minimal evolutionary costs on an adversary, as they must only modify an existing exploitation strategy to continue to be successful. The adversary does not need to abandon their existing strategy or develop a new strategy, just refine an existing one. There is an evolutionary cost associated with this but it will be less than if they had to abandon their current strategy and evolve a new one.
• Stabilizing selection pressures will tend to cost an adversary the least, as they do not need to modify their current strategies therefore experiencing no change in to their evolutionary costs. There may be evolutionary costs associated with stabilizing selection pressures as the maintenance of an adversary's strategies may have a cost associated with them. Stabilizing selection pressures are not likely to force an adversary to incur any additional evolutionary costs as they have already adapted to the environment, but even then an adversary may be able to reduce their costs further by evolving a more efficient method for existing in the environment.
  

Using the principles of selection pressures and evolutionary costs from evolutionary biology, the risk management process can be updated to anticipate how an adversary will respond to the survival strategies of a system. When responses to a risk are proposed, they should be investigated to see how an adversary could respond. In the case of SSH brute forcing, the rules act as a directional selection pressure which caused the attacker to modify but not abandon their strategy. With the implementation of virtualization throughout an environment, it can act as either a disruptive or stabilizing selection pressure on malware. Depending on the potential costs associated with an adversary's response, the one that is likely to inflict the highest evolutionary cost should be chosen as the solution. If a solution is chosen has little or no impact evolutionary cost on an adversary to over come, it will not be long before an attacker has compromised the system.

Predicting the resultant strategies is not trivial, but understanding the selection pressures involved may make the situation more manageable. In the case of the SSH brute force and the adoption of Virtualization some strategies can be determined based on the attributes of the strategy implemented. Inspecting the strategies that are found within the natural environment could provide additional insight into how an adversary could respond. Any of the following could also be potential responses.

• Some organisms have developed adaptations which advertise to others that they are something they are not, or they are poisonous. An adversary could mimic the behavior of the system employed. Malware such as Anti-Virus 2009 or Anti-Virus 360 appears to be anti-virus software which protects a user from attacks on the Internet when instead it is actually a Trojan.
  
• Like parasites subverting the central nervous systems of hosts, an adversary could exploit the strategy that is used to help the system survive. Malware can attempt to exploit vulnerabilities in anti-virus software to attack a system, as anti-malware software usually operates as a privileged service making it a priority target since it has access to the entire system in addition to protecting the system.
  
• Some animals have developed better camouflage to help mask there presence in the environment. A smaller and less noisy profile means that an attacker is less likely to detect their presence. Malware is moving to HTTP command and control channels to help mask its presence in the traffic being sent across the network.
• Another response is to completely abandon the current strategy, and develop a new strategy which catches an organism unprepared. As part of an experiment in evolutionary biology, a predatory lizard was introduced onto several islands which were inhabited by Anoles. Initially the average length of their legs increased, which allowed them to survive by running faster to evade their predators. Eventually the average leg length decreased as the Anoles were able to avoid their predators entirely by spending more time in the trees. Malware can react to countermeasures by simply avoiding the countermeasures entirely or attacking an information system at different layers. A worm can be written to exploit web applications instead of targeting flaws in the operating system.
  
• Sometimes the best response is not to respond to the strategy employed. If the counter strategy will only be infrequently encountered, it is often more cost effective to ignore it. In the case of the natural environment some predators that interact with prey populations interact so infrequently that it is more effective to not response as a population then to evolve a response. Malware authors should be aware that almost all analysis of their binaries will be conducted in a virtualized environment, yet not all malware encountered is able to detect when it is operating in a virtualized environment.
  

Each of different responses carries an associated evolutionary cost. Some of these like abandoning a strategy and evolving a new strategy can be high as the cost of evolve and develop a strategy are discarded and a new strategy must be evolved and developed. Other strategies can carry no additional evolutionary costs such as ignoring the threat and not modifying the current survival strategies.

The current risk management process has weaknesses when it is applied to an environment which evolving. The basic process is reactionary in nature and gives all of the initiative to the adversary and requires that the adversary first advertise their latest strategy before it could be countered. Instead of waiting for an adversary to attack an information system, the risk management methodology should include steps which attempt to determine how the current security strategies will force an adversary to adapt. Based the types of selection pressures that are applied to counter an adversary's strategy, anticipated actions can be made as to how an adversary will be forced to respond. When selecting among several different counter strategies, preference should be given to those strategies which have the highest evolutionary costs to counter (e.g. most likely disruptive selection pressures).

Disruptive/Stabilizing Selection Pressures and Virtualization

In evolutionary biology disruptive selection pressures are commonly seen when there is a radical change in the environment in which an entity is attempting to survive in. The more drastic the environmental change, the stronger the selection pressure that will be applied to the population. Sometimes the changes will be drastic enough that the population goes extinct, while in other cases the population will be able to evolve and adapt to the new environment. In information security, an emerging potentially drastic change is the application of virtualization through out the computing environment.

There have been a number of suggestions and even implemented systems which use Virtualization as a security measure. Some systems even treat it as the ultimate solution to malware propagation on the Internet. Aside from the increased overall complexity of the resulting system and requirements for management, using virtualization as a security measure will be a game changing event, but not one which solves the malware issue. Looking at the implementation of virtualization as a security mechanism from an evolutionary biology point of view, this virtualization strategy will act as both a disruptive and stabilizing selection pressure in the co-evolutionary system of information security.

Disruptive selection pressures cause an entity to abandon their current strategy and pursue a different strategy. These pressures select against those who employ a specific strategy. In the case of stabilizing selection, pressures act on an entity to reinforce their current strategy and selects against employing other strategies. There are two ways in which malware can respond to the wide spread adoption of virtualization. It can either abandon the items being virtualized or it can exploit virtualization to its advantage.

• In the first case, malware abandons operating in the virtualized layers of the operating system and applications. Virtualization acts as a disruptive selection pressure in which malware evolves to exploit the layers above and below the virtualized layers.
• In the second case, malware evolves to exploit the new virtualized environment. Virtualization has made new exploitable resources available and will act as a stabilizing selection pressure as malware beings to evolve strategies which exploits virtualization.

In the case of disruptive selection, malware's response will move out of the virtualized layers of the information system (e.g. the operating system and possibly the application environment) and into the layers either above or below the virtualization. The layers above the virtualization would be considered to operate within a browser environment. Virtualization can even be applied to specific applications such that if one is exploited, it will not affect the host operating system. Despite this fact, virtualization will not protect the system against attacks such as Cross Site Scripting (XSS), Cross Site Request Forgery (CRSF), Phishing, Sidejacking, and SQL Injection. It will not protect against attacks which exploit the user through social engineering and still allows malicious scripts to ex-filtrate private and/or sensitive information from the system.

Also, this disruptive selection pressure can cause malware to move down through layers towards the BIOS, firmware, and hardware of an information system. Generally virtualization will be able to protect an information system as data is being processed or once it has already been processed. If an attack ignores these layers, it can exploit the system without being detected. Fundamentally, virtualization trusts the hardware in which is it operating and this trust relationship can be exploited. There are a large number of places in which malware can hide on a system besides at the application and operating systems layers such as in BIOS, Firmware (e.g. a NIC) or even within the processor.

Evolutionary biologists have previously conducted experiments which focused on evolutionary adaptation of bacteria which demonstrated that given a resource limited environment bacteria can evolve by selection to fully exploit environmental changes. A population of E. coli was placed under controlled environmental conditions which allowed the organism to survive and maintain population levels. The bacteria essentially had a disruptive selection pressure applied to its main method of harvesting resources from the environment. The new environment contained resources which if a few changes were made to the metabolic process of the E. coli organism, it would all it to utilize the new resources which it would otherwise not be able to use. The bacteria's progress was measured throughout the experiment, and eventually the right mutations occurred and the bacteria's population grew exponentially as it was able to harvest additional resources in the environment.

Virtualization can act as a stabilizing selection pressure on the evolution of malware. Instead of causing malware to move to other layers of the system, virtualization offers new resources which malware may be able to exploit. Presently there is a significant number of malware that are capable of detecting virtualization but this detection exists to only prevent it from executing as most malware analysis workstations inspect malware inside a virtualized environment. Escapes from a virtualized environment have already been demonstrated, as have VM exploits. If virtualization becomes common through out the environment, malware will be able to evolve its strategies such that it can survive in this environment.

The widespread adoption of virtualization as an information security counter-strategy will in some cases provide no selection pressure on an attacker's strategy. Virtualization will also not address a number of exploitation strategies which exploit the interconnections between systems. It will not be able to provide a defense against man-in-the-middle attacks or attacks which focus on the protocols which are used to connect information systems together.

Lastly, it will take time to make a virtualized solution common in the environment. In the short term, the virtualized clients will have an advantage in that they occupy a small portion of the entire population, but as time passes the likelihood that malware can exploit this new virtualized strategy will increase. Like with the example of E. coli adapting to an environment which initially severely limits its fitness, eventually malware will be evolve to exploit its new environment. Rolling out virtualization to the entire population of computers will not be done over-night and it will take a few years. Unlike the E. coli which was suddenly exposed to an environment which hampered its fitness, malware will be more gradually exposed to virtualized environments. Despite the time difference in the exposure to the emergence of a selection pressure, just like the E. coli malware will be forced to change by its environment, allowing it to evolve the necessary adaptations which will allow it to survive. It is not a question of can it evolve, but rather how long it will take to evolve.

Simply using virtualization as a defense does not mean that a system is instantly protected against all existing malware strategies. It will stop some exploitation strategies but it is not a complete defense and can even increase the risk to the environment as virtualization adds software which must be secured in addition to the increased complexity to the system in its operation and management.

There are a number of directions in which using Virtualization as a common defense could force malware strategies to evolve. Malware could evolve under stabilizing selection pressures which would cause it to evolve strategies for escaping and exploiting the very software which is used to protect the system. Malware could also evolve under disruptive selection pressures and evolve strategies to target the hardware which has traditionally been assumed to be trusted. Attacks against Firmware, BIOS, CPU, NICs, and even the Trusted Platform Modules have been successfully demonstrated. Although virtualization is not the only selection pressure in causing the creation of hardware attacks, it will increase the selection pressure and force these attack strategies to move in that direction. Already there have been discussions and demonstrations about implementing System Management Mode (SMM) rootkits by poisoning the system's cache. Beyond that, using virtualization as an information security measure will not protect a system from scripted attacks, social engineering or man-in-the-middle attacks.

Selection Pressure, Yesterday's Strategies, Resource Exploitation and Evolutionary Costs

When attempting to think of information security from an evolutionary perspective, there are a few concepts from evolutionary biology to consider. Selection pressures, adaptive time lags, and resource/population exploitation are important to how an entity's strategies evolve.

Evolutionary pressures, selection agents, or selection pressures usually refer to the same entity within evolutionary biology; a thing or a force which causes an organism to respond and/or adapt. Selection pressures originate from the natural environment of the organisms and include things like: resource availability, changing/adverse environmental conditions, interspecies predation and intra-species competition. The more pronounced the selection pressure, the quicker an entity must respond in order to survive. Those entities that are not able to adapt (i.e. contain the required characteristics to survive) are eventually eliminated. Stronger selection pressures will eliminate maladapted entities more quickly than those which already are surviving or are able to acquire the necessary characteristics to survive.

Selection pressures can select for a characteristic to evolve in a directional, stabilizing or disruptive way. Directional selection pressures force a characteristic in a "direction." For example, directional selection pressures select for a larger or smaller characteristic. Stabilizing selection pressures force a characteristic to remain the same, and select against larger and smaller characteristics. Disruptive selection pressures select against a specific characteristic in the population. A disruptive selection pressure could select for the larger or smaller characteristic and select against the average value of the characteristic which results in the selecting characteristic to diverge.

In information security, the security controls that are implemented can be considered to be the survival strategies of an information system and even selection pressures acting upon an adversary. If an adversary does not have the ability to compromise any one of the implemented security controls, they will not be able to access the resources which the system is protecting. So in order to survive, an adversary must develop counter-strategies which are capable of exploiting the strategies that were implemented in order to survive.

Organizations should understand that their strategies will succeed and fail based on the counter strategies employed against them. While the root cause of a compromise is being analyzed, one should also investigate what selection pressures should be applied to move the organization in the direction towards secure business processes. If an organization consistently receives poor quality applications from their vendors, they should determine what selection pressures could be applied early in the process to affect the desired changes. Should the organization hold the developer responsible for a compromise of the application? The organization is contracted to provide an application that supports the business processes. A compromised application/system does not support the business goals of the organization.

Some selection pressures are strong enough that they will exert enough evolutionary pressure on a population that all of the resulting entities within the population are identical as a response to the selection pressures. Because of the strength of the selection pressure operating on the population, all of the variance of a characteristic has to be eliminated in order for members of the population to survive. Stronger selection pressures will remove the variance from the population faster than smaller selection pressures. Stated another way, some strategies exert enough of a filtering pressure that all entities must develop a specific counter strategy in order to survive.

Most malware and BotNets have a characteristic which is hard to escape; their reliance on a method to make initial contact with their controllers and join the BotNet. Initially these control channels were handled over IRC (this method has not been abandoned and is still in use), and since then they have now migrated to Peer-to-Peer communications. More recently the bots are attempting to contact their controllers via HTTP requests as Peer-to-Peer communications are filtered by boundary protection devices. Now these HTTP requests carry a name that must be looked up in DNS (e.g. part of a fast-flux DNS network). This method is becoming more common as organizational selection pressures push the bots in this direction. The reliance making initial contact with the bot-net is essentially a bottle neck which can be exploited. If the DNS look up is always a consistent or predictable string then it can be blocked by either filtering the appropriate Internet addresses even if they are part of a fast-flux network.

In evolutionary biology, it takes time for organisms to adapt to their environment. There is a time lag between when a counter strategy is employed against a population and when an entity has evolved a strategy to deal with the counter strategy. The current generation is better adapted to the previous environment than the one in which it exists (or selected for) based on conditions that existed previously. The current environment and the previous environment may have changed.

This lag commonly expresses itself in information security when systems are designed. If they are designed properly they are designed to counter all of the existing exploitation strategies that are known. Depending upon how long it takes to go from design to implementation and to delivery, the threat environment may have drastically changed. The delivered system may not be able to address all of the current threats in the environment and may need to be modified. Additionally a few years following the deployment of a system, if it is not updated, there may be emerging threats that the existing design is incapable of addressing.

This time lag also appears in the conflict between malware and anti-malware tools or attacks and intrusion detection/prevention systems, which rely on signatures to detect, identify and remove malware or attacks. A signature must be created to detect the malware, and pushes out to all of the clients before they can respond to a malware infection. In order to create a signature, a new malware variant must have been identified. Occasionally a rule will be created that was general enough that it may detect/prevent attacks that have not yet been implemented due to similarities in the way an attack's strategy attempts to exploit a target.

In evolutionary biology there is competition for resources and the easiest or the most abundant resources are typically exploited first. Sometimes the most abundant resources are not exploited right away as a population must evolve the ability to consume those resources. The abundance of a resource does not mean that it must be abundant every where, only that it is encountered frequently enough in the environment and there is sufficient competition for other resources that evolution will move an entity in that direction. Developing the ability to exploit a resource takes time and resources.

In information security this is similar to having a sufficient base of similar operating systems, browsers, databases, or frameworks to make the effort of developing an attack strategy worth while. This does not mean that just because a resource is not very common in the environment, it will not be exploited. Some operating systems will claim that they are more secure than the dominate competition, but as the number of systems increase so do the attacks against that platform. Although Microsoft Windows composes an overwhelming majority of the market, Apple has been gaining market share and the gains have been large enough that malware authors have begun to more frequently target the platform. Within the last year there has been an increase in the number of Trojans that target the Apple platform.

Although resource availability is important in determining if a platform will be exploited, another factor is apparent in the case of information security; the value of the resource being exploited. In the case of financial or government systems, which may be hosted on less common platforms there is additional incentive in targeting and exploiting these resources due to the perceived value of the system. There is some value in being able to compromise a home user's system (less so if it has a slower connection to the Internet) and there is more value in being able to compromise a web application server, but in reality some of the highest value resources are the databases which contain important information.

In short, selection pressures cause the survival strategies of entities to evolve. If they are unable to evolve, they will not survive. Responding to selection pressures, either directly (i.e. developing counter strategies) or indirectly (i.e. exploiting an unused resource) does not occur instantaneously, there is almost always delay between when the selection pressure first begins to work and a population's adaptive responses.