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1. Cyber Threat Intelligence Discovery using Machine Learning from the Dark Web

   https://doi.org/10.58729/1941-6687.1436  

   Zenebe, Azene ( January 2022 , Communications of the IIMA)

   Cyber threat intelligence (CTI) is an actionable information or insight an organization uses to understand potential vulnerabilities it does have and threats it is facing. One important CTI for proactive cyber defense is exploit type with possible values system, web, network, website or Mobile. This study compares the performance of machine learning algorithms in predicating exploit types using form posts in the dark web, which is a semi- structured dataset collected from dark web. The study uses the CRISP data science approach. The results of the study show that machine learning algorithms which are function-based including support vector machine and deep-learning using artificial neural network are more accurate than those algorithms which are based on tree including Random Forest and Decision-Tree for CTI discovery from semi-structured dataset. Future research will include the use of high-performance computing and advanced deep-learning algorithms. 

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2. Cybersecurity Threat Intelligence Augmentation and Embedding Improvement - A Healthcare Usecase

   https://doi.org/10.1109/ISI49825.2020.9280482  

   Sills, Matthew ; Ranade, Priyanka ; Mittal, Sudip ( November 2020 , 2020 IEEE International Conference on Intelligence and Security Informatics (ISI))

   null (Ed.)

   The implementation of Internet of Things (IoT) devices in medical environments, has introduced a growing list of security vulnerabilities and threats. The lack of an extensible big data resource that captures medical device vulnerabilities limits the use of Artificial Intelligence (AI) based cyber defense systems in capturing, detecting, and preventing known and future attacks. We describe a system that generates a repository of Cyber Threat Intelligence (CTI) about various medical devices and their known vulnerabilities from sources such as manufacturer and ICS-CERT vulnerability alerts. We augment the intelligence repository with data sources such as Wikidata and public medical databases. The combined resources are integrated with threat intelligence in our Cybersecurity Knowledge Graph (CKG) from previous research. The augmented graph embeddings are useful in querying relevant information and can help in various AI assisted cybersecurity tasks. Given the integration of multiple resources, we found the augmented CKG produced higher quality graph representations. The augmented CKG produced a 31% increase in the Mean Average Precision (MAP) value, computed over an information retrieval task. 

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3. Counteracting Dark Web Text-Based CAPTCHA with Generative Adversarial Learning for Proactive Cyber Threat Intelligence

   https://doi.org/10.1145/3505226  

   Zhang, Ning ; Ebrahimi, Mohammadreza ; Li, Weifeng ; Chen, Hsinchun ( June 2022 , ACM Transactions on Management Information Systems)

   Automated monitoring of dark web (DW) platforms on a large scale is the first step toward developing proactive Cyber Threat Intelligence (CTI). While there are efficient methods for collecting data from the surface web, large-scale dark web data collection is often hindered by anti-crawling measures. In particular, text-based CAPTCHA serves as the most prevalent and prohibiting type of these measures in the dark web. Text-based CAPTCHA identifies and blocks automated crawlers by forcing the user to enter a combination of hard-to-recognize alphanumeric characters. In the dark web, CAPTCHA images are meticulously designed with additional background noise and variable character length to prevent automated CAPTCHA breaking. Existing automated CAPTCHA breaking methods have difficulties in overcoming these dark web challenges. As such, solving dark web text-based CAPTCHA has been relying heavily on human involvement, which is labor-intensive and time-consuming. In this study, we propose a novel framework for automated breaking of dark web CAPTCHA to facilitate dark web data collection. This framework encompasses a novel generative method to recognize dark web text-based CAPTCHA with noisy background and variable character length. To eliminate the need for human involvement, the proposed framework utilizes Generative Adversarial Network (GAN) to counteract dark web background noise and leverages an enhanced character segmentation algorithm to handle CAPTCHA images with variable character length. Our proposed framework, DW-GAN, was systematically evaluated on multiple dark web CAPTCHA testbeds. DW-GAN significantly outperformed the state-of-the-art benchmark methods on all datasets, achieving over 94.4% success rate on a carefully collected real-world dark web dataset. We further conducted a case study on an emergent Dark Net Marketplace (DNM) to demonstrate that DW-GAN eliminated human involvement by automatically solving CAPTCHA challenges with no more than three attempts. Our research enables the CTI community to develop advanced, large-scale dark web monitoring. We make DW-GAN code available to the community as an open-source tool in GitHub. 

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4. Proactively Identifying Emerging Hacker Threats from the Dark Web: A Diachronic Graph Embedding Framework (D-GEF)

   https://doi.org/10.1145/3409289  

   Samtani, Sagar ; Zhu, Hongyi ; Chen, Hsinchun ( August 2020 , ACM Transactions on Privacy and Security)

   null (Ed.)

   Cybersecurity experts have appraised the total global cost of malicious hacking activities to be $450 billion annually. Cyber Threat Intelligence (CTI) has emerged as a viable approach to combat this societal issue. However, existing processes are criticized as inherently reactive to known threats. To combat these concerns, CTI experts have suggested proactively examining emerging threats in the vast, international online hacker community. In this study, we aim to develop proactive CTI capabilities by exploring online hacker forums to identify emerging threats in terms of popularity and tool functionality. To achieve these goals, we create a novel Diachronic Graph Embedding Framework (D-GEF). D-GEF operates on a Graph-of-Words (GoW) representation of hacker forum text to generate word embeddings in an unsupervised manner. Semantic displacement measures adopted from diachronic linguistics literature identify how terminology evolves. A series of benchmark experiments illustrate D-GEF's ability to generate higher quality than state-of-the-art word embedding models (e.g., word2vec) in tasks pertaining to semantic analogy, clustering, and threat classification. D-GEF's practical utility is illustrated with in-depth case studies on web application and denial of service threats targeting PHP and Windows technologies, respectively. We also discuss the implications of the proposed framework for strategic, operational, and tactical CTI scenarios. All datasets and code are publicly released to facilitate scientific reproducibility and extensions of this work. 

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5. Identifying and Categorizing Malicious Content on Paste Sites: A Neural Topic Modeling Approach

   https://doi.org/10.1109/ISI53945.2021.9624765  

   Vahedi, T ; Ampel, B ; Samtani, S and ( November 2021 , 2021 IEEE International Conference on Intelligence and Security Informatics)

   Malicious cyber activities impose substantial costs on the U.S. economy and global markets. Cyber-criminals often use information-sharing social media platforms such as paste sites (e.g., Pastebin) to share vast amounts of plain text content related to Personally Identifiable Information (PII), credit card numbers, exploit code, malware, and other sensitive content. Paste sites can provide targeted Cyber Threat Intelligence (CTI) about potential threats and prior breaches. In this research, we propose a novel Bidirectional Encoder Representation from Transformers (BERT) with Latent Dirichlet Allocation (LDA) model to categorize pastes automatically. Our proposed BERTLDA model leverages a neural network transformer architecture to capture sequential dependencies when representing each sentence in a paste. BERT-LDA replaces the Bag-of-Words (BoW) approach in the conventional LDA with a Bag-of-Labels (BoL) that encompasses class labels at the sequence level. We compared the performance of the proposed BERT-LDA against the conventional LDA and BERT-LDA variants (e.g., GPT2-LDA) on 4,254,453 pastes from three paste sites. Experiment results indicate that the proposed BERT-LDA outperformed the standard LDA and each BERT-LDA variant in terms of perplexity on each paste site. Results of our BERTLDA case study suggest that significant content relating to hacker community activities, malicious code, network and website vulnerabilities, and PII are shared on paste sites. The insights provided by this study could be used by organizations to proactively mitigate potential damage on their infrastructure. 

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