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Protecting Against Insider Threats with Enterprise Architecture Patterns

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The 2011 CyberSecurity Watch survey revealed that 27 percent of cybersecurity attacks against organizations were caused by disgruntled, greedy, or subversive insiders, employees, or contractors with access to that organization's network systems or data. Of the 607 survey respondents, 43 percent view insider threat attacks as more costly and cited not only a financial loss but also damage to reputation, critical system disruption, and loss of confidential or proprietary information. For the Department of Defense (DoD) and industry, combating insider threat attacks is hard due to the authorized physical and logical access of insiders to organization systems and intimate knowledge of organizations themselves.

Unfortunately, current countermeasures to insider threat are largely reactive, resulting in information systems storing sensitive information with inadequate protection against the range of procedural and technical vulnerabilities commonly exploited by insiders. This posting describes the work of researchers at the CERT® Insider Threat Centerto help protect next-generation DoD enterprise systems against insider threats by capturing, validating, and applying enterprise architectural patterns.

Enterprise architectural patterns are organizational patterns that involve the full scope of enterprise architecture concerns, including people, processes, technology, and facilities. This broad scope is necessary due to the fact that insiders have authorized access to systems--not only online access but physical access too. Our understanding of insider threat stems from a decade of experience cataloging more than 700 cases of malicious insider crime against information systems and assets, including over 120 cases of espionage involving classified national security information.

Our experience reveals that malicious insiders exploit vulnerabilities in business processes of victim organizations as often as they do detailed technical vulnerabilities. Likewise, our data analysis has identified well over 100 categories of weaknesses in enterprise architectures that allowed the insider attacks to occur. We have used this analysis to develop an insider threat vulnerability assessment method, based on qualitative models for insider IT sabotage and insider theft of intellectual property (IP) that characterize patterns of problematic behaviors seen in insider threat cases. We have also applied these models to identify insider threat best practices and technical insider threat controls.

For example, an organization must deal with the risk that departing insiders might take valuable IP with them. One set of practices and controls that helps reduce the risk of insider theft of IP is based on case data showing that most insiders who stole IP did so within 30 days prior to their forced or voluntary termination. The pattern describing this set of practices and controls helps balance the costs of monitoring employee behavior for suspicious actions with the risk of losing the organization's intellectual property.

Organizations aware of this pattern can ensure that the necessary agreements are in place (IP ownership and consent to monitoring), critical IP is identified, key departing insiders are monitored, and the necessary communication among departments takes place. At the point at which an insider resigns or is fired, technical monitoring and scrutiny of that employee's activities within a 30-day window of their termination date are increased. Actions taken upon and before employee termination are vital to ensuring IP is not compromised and the organization preserves its legal options.

Capturing our understanding of insider threat mitigations as architectural patterns allows us to translate effective solutions in forms useful to engineers who design DoD systems. As part of our research, we are analyzing the subset of insider IT sabotage cases from the CERT insider threat database. We are updating and refining our existing qualitative insider IT sabotage model to include a quantitative simulation capability intended to exhibit the predominate patterns of insider IT sabotage behavior.

We are using a system dynamics approach to model and analyze the holistic behavior of complex problems as they evolve over time. System dynamics modeling and simulation makes it easier for us to understand and communicate the nature of problematic insider threat behavior as an enterprise architectural concern. After validating that simulating the problem model accurately represents the historical behavior of the problem--and does so for the right reasons--the next step is to examine the enterprise-level architectural insider threat controls proposed to help mitigate it. Our research will focus on two aspects:

  1. Are those controls effective against insider threats? For example, do the controls mitigate the problematic behavior exhibited in the simulation model?
  2. Do those controls introduce negative unintended consequences? For example, even if the controls are effective against the threat, do they unintentionally undermine organizational trust and reduce team performance?

A key challenge in our research is the difficulty associated with testing these controls in an operational environment. One manifestation of this problem is in the form of unknown false positive rates associated with insider threat controls. From the perspective of technical observations and resource usage, most malicious insiders behave as their non-malicious counterparts do. We therefore expect that poorly-designed controls will overwhelm operators with false positives. Controls are also hard to test operationally because insider attacks occur relatively infrequently, but nevertheless result in huge damages for victim organizations.

To meet these challenges, we are using system dynamics modeling and simulation to identify and test enterprise architectural patterns to protect against insider threat to current DoD systems. We are interviewing members of the DoD who have expressed interest in information security controls to mitigate the insider threat. These steps are enabling us to characterize the baseline enterprise architecture, which represents their operational architecture as a starting point for our analysis.

Identified architectural patterns will be applied to modify the baseline architecture to better protect against insider threat. The basis for establishing the efficacy of the architectural patterns is system dynamics simulation-based testing. The experiments conducted in the simulation environment provide a body of evidence that supports strong hypotheses going into pilot testing within organizations.

Enterprise architectural patterns developed through our research will enable coherent reasoning about how to design--and to a lesser extent implement--DoD enterprise systems to protect against insider threat. Instead of being faced with vague security requirements and inadequate security technologies, DoD system designers will have a coherent set of architectural patterns they can apply to develop effective strategies against insider threat in a more timely and confident manner. Confidence in these patterns will be enhanced through our use of established theories in related areas and the scientific approach of using system dynamics simulation models to test key hypotheses prior to pilot testing. We expect our research results will improve DoD enterprise, system, and software architectures to reduce the number and impact of insider attacks on DoD information assets.

We will be periodically blogging about the progress of this work. Please feel free to leave your comments below and we will reply.

Additional Resources:

For more information about the work of the CERT Insider Threat Center, please visit

To read a report about preliminary technical controls derived from insider threat data, Deriving Candidate Technical Controls and Indicators of Insider Attack from Socio-Technical Models and Data, please visit

To read a report about our insider threat modeling, A Preliminary Model of Insider Theft of Intellectual Property, please visit

To read the CERT Insider Threat blog, please visit

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