As power grids have evolved, IT has become integral to maintaining reliable power. While providing operators improved situational awareness and the ability to rapidly respond to dynamic situations, IT concurrently increases the cyberattack threat surface – as recent grid attacks such as Blackenergy and Crashoverride illustrate. To defend against such attacks, modern power grids require a system that can maintain reliable power during attacks and detect when these attacks occur to allow for a timely response. To help address limitations of prior work, we propose DRAGON– deep reinforcement learning for autonomous grid operation and attack detection, which (i) autonomously learns how to maintain reliable power operations while (ii) simultaneously detecting cyberattacks. We implement DRAGON and evaluate its effectiveness by simulating different attack scenarios on the IEEE 14 bus power transmission system model. Our experimental results show that DRAGON can maintain safe grid operations 225.5% longer than a state-of-the-art autonomous grid operator. Furthermore, on average, our detection method reports a true positive rate of 92.9% and a false positive rate of 11.4%, while also reducing the false negative rate by 63.1% compared to a recent attack detection method.

Malware analysis aims to understand how malicious software carries out actions necessary for a successful attack and identify the possible impacts of the attack. While there has been substantial research focused on malware analysis and it is an important tool for practitioners in industry, the overall malware analysis process used by practitioners has not been studied. As a result, an understanding of common malware analysis workflows and their goals is lacking. A better understanding of these workflows could help identify new research directions that are impactful in practice. In order to better understand malware analysis processes, we present the results of a user study with 21 professional malware analysts with diverse backgrounds who work at 18 different companies. The study focuses on answering three research questions: (1) What are the different objectives of malware analysts in practice?, (2) What comprises a typical professional malware analyst workflow, and (3) When analysts decide to conduct dynamic analysis, what factors do they consider when setting up a dynamic analysis system? Based on participant responses, we propose a taxonomy of malware analysts and identify five common analysis workflows. We also identify challenges that analysts face during the different stages of their workflow. From the results of the study, we propose two potential directions for future research, informed by challenges described by the participants. Finally, we recommend guidelines for developers of malware analysis tools to consider in order to improve the usability of such tools.

We introduce an algorithm for model-based hierarchical reinforcement learning to acquire self-contained transition and reward models suitable for probabilistic planning at multiple levels of abstraction. We call this framework Planning with Abstract Learned Models (PALM). By representing subtasks symbolically using a new formal structure, the lifted abstract Markov decision process (L-AMDP), PALM learns models that are independent and modular. Through our experiments, we show how PALM integrates planning and execution, facilitating a rapid and efficient learning of abstract, hierarchical models. We also demonstrate the increased potential for learned models to be transferred to new and related tasks.

Compromising a website that is routinely visited by employees of a targeted organization has become a popular technique for nation-state level adversaries to penetrate an enterprise's network. This technique, dubbed a "watering hole" attack, leverages a compromised website to serve as a stepping stone into the true victims' network. Despite watering hole attacks being one of the main techniques used by attackers to achieve the initial compromise stage of the cyber kill chain, there has been relatively little research related to detecting or investigating complex watering hole attacks. While there is existing work that seeks to detect malicious modifications made to an otherwise benign website, we argue that simply detecting that the website is compromised is only the first stage of the investigation. In this paper, we propose Mnemosyne, a postmortem forensic analysis engine that relies on browser-based attack provenance to accurately reconstruct, investigate, and assess the ramifications of watering hole attacks. Mnemosyne relies on a lightweight browser-modification-free auditing daemon to passively collect causality logs related to the browser's execution. Next, Mnemosyne applies a set of versioning techniques on top of these causality logs to precisely pinpoint when the website was compromised and what modifications were made by the adversary. Following this step, Mnemosyne relies on a novel user-level analysis to assess how the malicious modifications affected the targeted enterprise and seeks to identify exactly which employees fell victim to the attack. Throughout our extensive evaluation, we found that Mnemosyne's forensic analysis engine was able to identify the true victims in all seven real-world watering hole scenarios, while also reducing the amount of manual analysis required by the forensic analyst by 98.17% on average.

In Android malware detection, recent work has shown that using contextual information of sensitive API invocation in the modeling of applications is able to improve the classification accuracy. However, the improvement brought by this context-awareness varies depending on how this information is used in the modeling. In this paper, we perform a comprehensive study on the effectiveness of using the contextual information in prior state-of-the-art detection systems. We find that this information has been "over-used" such that a large amount of non-essential metadata built into the models weakens the generalizability and longevity of the model, thus finally affects the detection accuracy. On the other hand, we find that the entrypoint of API invocation has the strongest impact on the classification correctness, which can further improve the accuracy if being properly captured. Based on this finding, we design and implement a lightweight, circumstance-aware detection system, named "PIKADROID" that only uses the API invocation and its entrypoint in the modeling. For extracting the meaningful entrypoints, PIKADROID applies a set of static analysis techniques to extract and sanitize the reachable entrypoints of a sensitive API, then constructs a frequency model for classification decision. In the evaluation, we show that this slim model significantly improves the detection accuracy on a data set of 23,631 applications by achieving an f-score of 97.41%, while maintaining a false positive rating of 0.96%.