Biblio

Mitigation of dangers posed by authorized and trusted insiders to the organization is a challenging Cyber Security issue. Despite state-of-the-art cyber security practices, malicious insiders present serious threat for the enterprises due to their wider access to organizational resources (Physical, Cyber) and good knowledge of internal processes with potential vulnerabilities. The issue becomes particularly important for isolated (air-gapped) computer networks, normally used by security sensitive organizations such as government, research and development, critical infrastructure (e.g. power, nuclear), finance, and military. Such facilities are difficult to compromise from outside; however, are quite much prone to insider threats. Although many insider threat taxonomies exist for generic computer networks; yet, the existing taxonomies do not effectively address the issue of Insider Threat in isolated computer networks. Thereby, we have developed an insider threat taxonomy specific to isolated computer networks focusing on actions performed by the trusted individual(s), Our methodology is to identify limitations in existing taxonomies and map real world insider threat cases on proposed taxonomy. We argue that for successful attack in an isolated computer network, the attack must manifest in both Physical and Cyber world. The proposed taxonomy systematically classifies different aspects of the problem into separate dimensions and branches out these dimensions into further sub-categories without loss of general applicability. Our multi-dimensional hierarchical taxonomy provides comprehensive treatment of the insider threat problem in isolated computer networks; thus, improving situational awareness of the security analyst and helps in determining proper countermeasures against perceived threats. Although many insider threat taxonomies exist for generic computer networks; yet, the existing taxonomies do not effectively address the issue of Insider Threat in isolated computer networks. Thereby, we have developed an insider threat taxonomy specific to isolated computer networks focusing on actions performed by the trusted individual(s), Our methodology is to identify limitations in existing taxonomies and map real world insider threat cases on proposed taxonomy. We argue that for successful attack in an isolated computer network, the attack must manifest in both Physical and Cyber world. The proposed taxonomy systematically classifies different aspects of the problem into separate dimensions and branches out these dimensions into further sub-categories without loss of general applicability. Our multi-dimensional hierarchical taxonomy provides comprehensive treatment of the insider threat problem in isolated computer networks; thus, improving situational awareness of the security analyst and helps in determining proper countermeasures against perceived threats. The proposed taxonomy systematically classifies different aspects of the problem into separate dimensions and branches out these dimensions into further sub-categories without loss of general applicability. Our multi-dimensional hierarchical taxonomy provides comprehensive treatment of the insider threat problem in isolated computer networks; thus, improving situational awareness of the security analyst and helps in determining proper countermeasures against perceived threats.

In the past air-gapped systems that are isolated from networks have been considered to be very secure. Yet there have been reports of such systems being breached. These breaches have shown to use unconventional means for communication also known as covert channels such as Acoustic, Electromagnetic, Magnetic, Electric, Optical, and Thermal to transfer data. In this paper, a review of various attack methods that can compromise an air-gapped system is presented along with a summary of how efficient and dangerous a particular method could be. The capabilities of each covert channel are listed to better understand the threat it poses and also some countermeasures to safeguard against such attack methods are mentioned. These attack methods have already been proven to work and awareness of such covert channels for data exfiltration is crucial in various industries.