Smart technologies, such as the Internet of Things (IoT), cloud computing, and artificial intelligence (AI), are being adopted in cities and transforming them into smart cities. In smart cities, various network technologies, such as the Internet and IoT, are combined to exchange real-time information, making the everyday lives of their residents more convenient. However, there is a lack of systematic research on cybersecurity and cyber forensics in smart cities. This paper presents a comprehensive review and survey of cybersecurity and cyber forensics for smart cities. We analysed 154 papers that were published from 2015 to 2022 and proposed a new framework based on a decade of related research papers. We identified four major areas and eleven sub-areas for smart cities. We found that smart homes and the IoT were the most active research areas within the cybersecurity field. Additionally, we found that research on cyber forensics for smart cities was relatively limited compared to that on cybersecurity. Since 2020, there have been many studies on the IoT (which is a technological component of smart cities) that have utilized machine learning and deep learning. Due to the transmission of large-scale data through IoT devices in smart cities, ML and DL are expected to continue playing critical roles in smart city research.

Ransomware attacks pose a serious threat to computer networks, causing widespread disruption to individual, corporate, governmental, and critical national infrastructures. To mitigate their impact, extensive research has been conducted to analyze ransomware operations. However, most prior studies have focused on decryption, post-infection response, or general family-level classification for performance evaluation, with limited attention to linking classification accuracy to each family’s threat level and behavioral patterns. In this study, we propose a classification framework for the most dangerous ransomware families targeting Windows systems, correlating model performance with defined threat levels (high, medium, and low) based on API call patterns. Two independent datasets were used, extracted from VirusTotal and Cuckoo Sandbox, and a cross-source evaluation strategy was applied, alternating training and testing roles between datasets to assess generalization ability and minimize source bias. The results show that the proposed approach, particularly when using XGBoost and LightGBM, achieved accuracy rates ranging from 84 to 100% across datasets. These findings confirm the effectiveness of our method in accurately classifying ransomware families while accounting for their severity and behavioral characteristics.