More than three decades after its introduction, Role-Based Access Control (RBAC) continues to be one of the most widely used access control models in organizations. This popularity stems from its simplicity, the reduced risk of errors, and its clear alignment with business processes. However, the primarily manual nature of data management in RBAC systems, coupled with a lack of oversight, can lead to various inefficiencies over time. These may include roles that are not assigned to any users or roles that have identical sets of permissions. Such issues can slow down systems that rely on these data and, more critically, complicate auditing processes, increasing the risk of security gaps and compliance violations.In this paper, we present a taxonomy of inefficiencies that can arise in RBAC data over time and propose a framework for detecting these inefficiencies. We specifically focus on the most resource-intensive inefficiencies, namely roles that share the same or similar users or permissions. To address these issues, we propose three detection methods, including a custom algorithm we developed. We evaluate these methods using synthetic datasets, demonstrating that our algorithm significantly outperforms baseline approaches. Its efficiency allows us to identify these inefficiencies even on a standard laptop used by large organizations. Furthermore, we applied our framework to real RBAC data from a large organization with over 60,000 employees and uncovered a substantial number of inefficiencies, highlighting its practical value in real-world scenarios. ... Read more

Endpoint Detection and Response (EDR) systems provide continuous monitoring, threat detection, and response capabilities. This has driven their widespread adoption in enterprises, making them a key part of an enterprise's security architecture. However, EDR systems are a double-edged sword, and in this study, we demonstrate how this class of systems can be employed for offensive use. Unlike prior studies that focused on evasion and tampering, we introduce the new concept of EDR repurposing, which we call EvilEDR. Our analysis shows that EvilEDR can be used to execute arbitrary commands via the response console, transfer tools, exfiltrate data, and passively collect system information to facilitate further exploitation and lateral movement. EvilEDR operates covertly, masquerading as a legitimate process and communicating seamlessly with trusted domains. Additionally, we show that EvilEDR can impair defenses by registering its own EPP as the default. It can also isolate the host from the network, severing telemetry and response channels essential for enterprise defense mechanisms. Fortunately, EvilEDR can be effectively detected and mitigated, and in this paper, we propose concrete and actionable defense strategies to achieve this. ... Read more

Large- and medium-sized organizations employ various security systems to protect their assets. These systems, often developed by different vendors, focus on different threats and usually work independently. They generate separate and voluminous alerts that have to be monitored and analyzed by often overburdened security analysts. Prior work has tried to support analysts by better correlating and prioritizing alerts. In this work, we propose to combine the wisdom of individual security systems using an Integration Layer (IL). We validated our idea by deploying the IL in a large global organization (50,000+ employees) running four very different security detection systems. We did so by using end-to-end red-team exercises to generate real attack data. For training, we labeled our dataset with evaluations directly from the incident response team instead of using the escalated decisions of the first/second tier Security Operation Center (SOC) analysts as in prior works. We showed that our approach considerably reduces the number of alerts requiring investigation while maintaining very high performance on multi-step attack detection - Matthews correlation coefficient (MCC) reaches 0.998. The substantial dependence of the model on features derived from the different security systems supports the viability of our integration methodology. The explainability layer added to our system gives analysts insights into why a particular case is marked as an attack or non-attack. Based on the test results, our approach has been added to the production setup. ... Read more

A reduction in phishing threats is of increasing importance to organizations. One part of this effort is to provide training to employees, so that they are able to identify and avoid phishing emails. Yet further, simulated phishing emails are used to test whether employees will both identify and report a suspicious email. We worked with a partner bank to examine a repository of many thousands of reported emails from a behavioural perspective. We divide reported emails into categories and examine reporting trends over time relative to training and phishing simulation campaigns. Among our findings, the level of reporting of benign emails is comparable to the number of malicious emails reported, and we see indications that training and simulations amplify the reporting of benign emails. Our analysis uncovers reporting patterns for unique reporters per email campaign as a promising indicator for the security-related culture around phishing prevention. Evidence from our analysis informs recommendations, such as providing reporting infrastructure for reporting not only malicious emails, but also benign but suspicious work-related emails, in a manner that minimises the disruption for users erring on the side of caution when assessing emails. ... Read more