The openness and extensibility of Android have made it a popular platform for smart phones and a strong candidate to drive the Internet-of-Things. Due to its popularity and functionality, it is the main target of malicious software (malware). Malware poses a serious threat to user privacy, money, equipment and file integrity. In such context, by studying the actions of malware, this work develops a novel framework SEDMDroid to detect Android malware, based on an enhanced stacking ensemble of deep learning algorithm. This stacking ensemble of deep learning method is a two-tier architecture, which includes an ensemble of base Multi-Layer Perception (MLP) classifiers and a fusion Support Vector Machine (SVM) classifier. The essences of this architecture are a double disturbance strategy through disturbance of the sample and the feature space to guarantee the accuracy and diversity of the base classifiers, and to learn the implicit supplementary information from the output of the trained base classifiers to optimize the classification efficiency. The proposed method is evaluated using a dataset with multi-level static features, which covers permission, sensitive API, monitoring system event and permission-rate, and the average accuracy is 89.29%.

Website Fingerprinting (WF) is a network traffic mining technique for anonymous traffic identification, which enables a local adversary to identify the target website that an anonymous network user is browsing. WF attacks based on deep convolutional neural networks (CNN) get the state-of-the-art anonymous traffic classification performance. However, due to the locality restriction of CNN architecture for feature extraction on sequence data, these methods ignore the temporal feature extraction in the anonymous traffic analysis. In this paper, we present Website Fingerprinting Transformer (WF-Transformer), a novel anonymous network traffic analysis method that leverages Transformer networks for temporal feature extraction of traffic traces and improves the classification performance of Tor encrypted traffic. The architecture of WF-Transformer is specially designed for traffic trace processing and can classify anonymous traffic effectively. Furthermore, we evaluate the performance of WF-Transformer in both closed-world and open-world scenarios. In the closed-world scenario, WF-Transformer attains 99.1% accuracy on Tor traffic without defenses, better than state-or-the-art attacks, and archives 92.1% accuracy on the traces defended by WTF-PAD method. In the open-world scenario, WF-Transformer has better precision and recall on both defended and non-defended traces. Furthermore, WF-Transformer with a short input length (2000 cells) outperforms the DF method with a long input length (5000 cells).

Android is a growing target for malicious software (malware) because of its popularity and functionality. Malware poses a serious threat to users’ privacy, money, equipment and file integrity. A series of data-driven malware detection methods were proposed. However, there exist two key challenges for these methods: (1) how to learn effective feature representation from raw data; (2) how to reduce the dependence on the prior knowledge or human labors in feature learning. Inspired by the success of deep learning methods in the feature representation learning community, we propose a malware detection framework which starts with learning rich-features by a novel unsupervised feature learning algorithm Merged Sparse Auto-Encoder (MSAE). In order to extract more compact and discriminative feature from the rich-features to further boost the malware detection capability, a hybrid deep network learning algorithm Stacked Hybrid Learning MSAE and SDAE (SHLMD) is established by further incorporating a classical deep learning method Stacked Denoising Auto-encoders (SDAE). After that, we feed the feature learned by MSAE and SHLMD respectively to classification algorithms, e.g., Support Vector Machine (SVM) or K-NearestNeighbor (KNN), to train a malware detection model. Evaluation results on two real-world datasets demonstrate that SHLMD achieves 94.46 and 90.57 percent accuracy respectively, which outperforms the classical unsupervised feature representation learning Sparse Auto-encoder (SAE). MSAE performs similarly to SAE. SHLMD can further improve the performance of MSAE and the supervised fine-tuned method SDAE. Besides, we compare the performance of our methods with that of state-of-the-art detection approaches, including classical deep-learning-based methods. Extensive experiments show that our proposed methods are effective enough to detect Android malware.

Smart contracts have gained extensive adoption across diverse industries, including finance, supply chain, and the Internet of Things. Nevertheless, the surge in security incidents of smart contracts over recent years has led to substantial economic losses. Therefore, ensuring the security of smart contracts has become a critical and complex challenge in both academic and industrial domains. Based on 539 real-world security incidents in the Ethereum platform and audit reports from 10 authoritative auditing institutions, we summarize 27 types of exploited security vulnerabilities and draw insights into their principles, typical cases, relevant research and recommended prevention strategies. Besides, we also gather 7 other potentially threatening vulnerability types as supplements. On this basis, we conduct an in-depth analysis of the root causes of vulnerabilities and further formulate eight safety practical rules. Moreover, we perform a comprehensive review of 178 recent papers on smart contract security analysis, classifying detection methods into formal verification, fuzz testing, machine learning, program analysis, and others. For each category, we seize the specific detection tools and analyze them comprehensively. Then, we conduct an extensive analysis and synthesis from various angles, presenting a comprehensive overview of the current research landscape in smart contract security detection. We also discuss current on-chain and off-chain repair methods. Finally, this review outlines major challenges and highlights potential areas for future research in this field