The reliance on expert knowledge-required for analysing security logs and performing security audits-has created an unhealthy balance, where many computer users are not able to correctly audit their security configurations and react to potential security threats. The decreasing cost of IT and the increasing use of technology in domestic life are exacerbating this problem, where small companies and home IT users are not able to afford the price of experts for auditing their system configuration. In this paper, we present GraphBAD, a graph-based analysis tool that is able to analyse security configurations in order to identify anomalies that could lead to potential security risks. GraphBAD, which does not require any prior domain knowledge, generates graph-based models from security configuration data and, by analysing such models, is able to propose mitigation plans that can help computer users in increasing the security of their systems. A large experimental analysis, conducted on both publicly available (the well-known KDD dataset) and synthetically generated testing sets (file system permissions), demonstrates the ability of GraphBAD in correctly identifying security configuration anomalies and suggesting appropriate mitigation plans.
KEYWORDSanomaly detection, graph structure, log files, security auditing, SIEM
INTRODUCTIONAuditing security configurations is the process of searching for anomalies that potentially expose a vulnerability of a considered system. The term Security Information and Event Management (SIEM) is often used to describe the process of monitoring audit logs and security configurations to identify vulnerabilities. Given the complexity of the task, there is a heavy reliance on expert knowledge, which is required for understanding the different security configurations. This reliance has two main drawbacks: first, expert knowledge can be incomplete or erroneous; second, the high cost of security experts makes it infeasible for many users to correctly configure the security of their Information Technology (IT) systems. Therefore, in many cases, unseen weaknesses, which can be exploited, will remain in the configuration. Clearly, auditing security configurations is a critical problem for organisations that significantly rely on their IT infrastructure for undertaking business. For this reason, many companies frequently employ a third party security auditing company to examine their IT infrastructure to identify weaknesses and suggest suitable mitigation plans (named as penetration testing 1,2 ). Although businesses are prepared to pay a premium for maintaining their security, the average home IT user or small companies are left to maintain their own IT security. Furthermore, the decreasing cost of IT and the increasing use of technology in domestic life are exacerbating this problem.These limitations are heightened by the following factors. (i) The complexity of computational infrastructure-the cyber-physical platform on which security is attained-is increasing, and the technological landscape i...