Diverse Multimedia Layout Generation with Multi Choice Learning

Designing visually appealing layouts for multimedia documents containing text, graphs and images requires a form of creative intelligence. Modelling the generation of layouts has recently gained attention due to its importance in aesthetics and communication style. In contrast to standard prediction tasks, there are a range of acceptable layouts which depend on user preferences. For example, a poster designer may prefer logos on the top-left while another prefers logos on the bottom-right. Both are correct choices yet existing machine learning models treat layouts as a single choice prediction problem. In such situations, these models would simply average over all possible choices given the same input forming a degenerate sample. In the above example, this would form an unacceptable layout with a logo in the centre. In this paper, we present an auto-regressive neural network architecture, called LayoutMCL, that uses multi-choice prediction and winner-takes-all loss to effectively stabilise layout generation. LayoutMCL avoids the averaging problem by using multiple predictors to learn a range of possible options for each layout object. This enables LayoutMCL to generate multiple and diverse layouts from a single input which is in contrast with existing approaches which yield similar layouts with minor variations. Through quantitative benchmarks on real data (magazine, document and mobile app layouts), we demonstrate that LayoutMCL reduces Fr\'echet Inception Distance (FID) by 83-98% and generates significantly more diversity in comparison to existing approaches.

Masked Vector Quantization

Generative models with discrete latent representations have recently demonstrated an impressive ability to learn complex high-dimensional data distributions. However, their performance relies on a long sequence of tokens per instance and a large number of codebook entries, resulting in long sampling times and considerable computation to fit the categorical posterior. To address these issues, we propose the Masked Vector Quantization (MVQ) framework which increases the representational capacity of each code vector by learning mask configurations via a stochastic winner-takes-all training regime called Multiple Hypothese Dropout (MH-Dropout). On ImageNet 64$\times$64, MVQ reduces FID in existing vector quantization architectures by up to $68\%$ at 2 tokens per instance and $57\%$ at 5 tokens. These improvements widen as codebook entries is reduced and allows for $7\textit{--}45\times$ speed-up in token sampling during inference. As an additional benefit, we find that smaller latent spaces lead to MVQ identifying transferable visual representations where multiple can be smoothly combined.

Tracking Dataset IP Use in Deep Neural Networks

Training highly performant deep neural networks (DNNs) typically requires the collection of a massive dataset and the use of powerful computing resources. Therefore, unauthorized redistribution of private pre-trained DNNs may cause severe economic loss for model owners. For protecting the ownership of DNN models, DNN watermarking schemes have been proposed by embedding secret information in a DNN model and verifying its presence for model ownership. However, existing DNN watermarking schemes compromise the model utility and are vulnerable to watermark removal attacks because a model is modified with a watermark. Alternatively, a new approach dubbed DEEPJUDGE was introduced to measure the similarity between a suspect model and a victim model without modifying the victim model. However, DEEPJUDGE would only be designed to detect the case where a suspect model's architecture is the same as a victim model's. In this work, we propose a novel DNN fingerprinting technique dubbed DEEPTASTER to prevent a new attack scenario in which a victim's data is stolen to build a suspect model. DEEPTASTER can effectively detect such data theft attacks even when a suspect model's architecture differs from a victim model's. To achieve this goal, DEEPTASTER generates a few adversarial images with perturbations, transforms them into the Fourier frequency domain, and uses the transformed images to identify the dataset used in a suspect model. The intuition is that those adversarial images can be used to capture the characteristics of DNNs built on a specific dataset. We evaluated the detection accuracy of DEEPTASTER on three datasets with three model architectures under various attack scenarios, including transfer learning, pruning, fine-tuning, and data augmentation. Overall, DEEPTASTER achieves a balanced accuracy of 94.95%, which is significantly better than 61.11% achieved by DEEPJUDGE in the same settings.

Profiler: Profile-Based Model to Detect Phishing Emails

Email phishing has become more prevalent and grows more sophisticated over time. To combat this rise, many machine learning (ML) algorithms for detecting phishing emails have been developed. However, due to the limited email data sets on which these algorithms train, they are not adept at recognising varied attacks and, thus, suffer from concept drift; attackers can introduce small changes in the statistical characteristics of their emails or websites to successfully bypass detection. Over time, a gap develops between the reported accuracy from literature and the algorithm's actual effectiveness in the real world. This realises itself in frequent false positive and false negative classifications. To this end, we propose a multidimensional risk assessment of emails to reduce the feasibility of an attacker adapting their email and avoiding detection. This horizontal approach to email phishing detection profiles an incoming email on its main features. We develop a risk assessment framework that includes three models which analyse an email's (1) threat level, (2) cognitive manipulation, and (3) email type, which we combine to return the final risk assessment score. The Profiler does not require large data sets to train on to be effective and its analysis of varied email features reduces the impact of concept drift. Our Profiler can be used in conjunction with ML approaches, to reduce their misclassifications or as a labeller for large email data sets in the training stage. We evaluate the efficacy of the Profiler against a machine learning ensemble using state-of-the-art ML algorithms on a data set of 9000 legitimate and 900 phishing emails from a large Australian research organisation. Our results indicate that the Profiler's mitigates the impact of concept drift, and delivers 30% less false positive and 25% less false negative email classifications over the ML ensemble's approach.

Deception for Cyber Defence: Challenges and Opportunities

Deception is rapidly growing as an important tool for cyber defence, complementing existing perimeter security measures to rapidly detect breaches and data theft. One of the factors limiting the use of deception has been the cost of generating realistic artefacts by hand. Recent advances in Machine Learning have, however, created opportunities for scalable, automated generation of realistic deceptions. This vision paper describes the opportunities and challenges involved in developing models to mimic many common elements of the IT stack for deception effects.

Transformer-Based Language Models for Software Vulnerability Detection: Performance, Model's Security and Platforms

The large transformer-based language models demonstrate excellent performance in natural language processing. By considering the closeness of natural languages to the high-level programming language such as C/C++, this work studies how good are the large transformer-based language models detecting software vulnerabilities. Our results demonstrate the well performance of these models on software vulnerability detection. The answer enables extending transformer-based language models to vulnerability detection and leveraging superior performance beyond the natural language processing domain. Besides, we perform the model's security check using Microsoft's Counterfit, a command-line tool to assess the model's security. Our results find that these models are vulnerable to adversarial examples. In this regard, we present a simple countermeasure and its result. Experimenting with large models is always a challenge due to the requirement of computing resources and platforms/libraries & dependencies. Based on the experiences and difficulties we faced during this work, we present our recommendation while choosing the platforms to run these large models. Moreover, the popular platforms are surveyed thoroughly in this paper.

Towards Web Phishing Detection Limitations and Mitigation

Web phishing remains a serious cyber threat responsible for most data breaches. Machine Learning (ML)-based anti-phishing detectors are seen as an effective countermeasure, and are increasingly adopted by web-browsers and software products. However, with an average of 10K phishing links reported per hour to platforms such as PhishTank and VirusTotal (VT), the deficiencies of such ML-based solutions are laid bare. We first explore how phishing sites bypass ML-based detection with a deep dive into 13K phishing pages targeting major brands such as Facebook. Results show successful evasion is caused by: (1) use of benign services to obscure phishing URLs; (2) high similarity between the HTML structures of phishing and benign pages; (3) hiding the ultimate phishing content within Javascript and running such scripts only on the client; (4) looking beyond typical credentials and credit cards for new content such as IDs and documents; (5) hiding phishing content until after human interaction. We attribute the root cause to the dependency of ML-based models on the vertical feature space (webpage content). These solutions rely only on what phishers present within the page itself. Thus, we propose Anti-SubtlePhish, a more resilient model based on logistic regression. The key augmentation is the inclusion of a horizontal feature space, which examines correlation variables between the final render of suspicious pages against what trusted services have recorded (e.g., PageRank). To defeat (1) and (2), we correlate information between WHOIS, PageRank, and page analytics. To combat (3), (4) and (5), we correlate features after rendering the page. Experiments with 100K phishing/benign sites show promising accuracy (98.8%). We also obtained 100% accuracy against 0-day phishing pages that were manually crafted, comparing well to the 0% recorded by VT vendors over the first four days.

Integrity Fingerprinting of DNN with Double Black-box Design and Verification

Cloud-enabled Machine Learning as a Service (MLaaS) has shown enormous promise to transform how deep learning models are developed and deployed. Nonetheless, there is a potential risk associated with the use of such services since a malicious party can modify them to achieve an adverse result. Therefore, it is imperative for model owners, service providers, and end-users to verify whether the deployed model has not been tampered with or not. Such verification requires public verifiability (i.e., fingerprinting patterns are available to all parties, including adversaries) and black-box access to the deployed model via APIs. Existing watermarking and fingerprinting approaches, however, require white-box knowledge (such as gradient) to design the fingerprinting and only support private verifiability, i.e., verification by an honest party. In this paper, we describe a practical watermarking technique that enables black-box knowledge in fingerprint design and black-box queries during verification. The service ensures the integrity of cloud-based services through public verification (i.e. fingerprinting patterns are available to all parties, including adversaries). If an adversary manipulates a model, this will result in a shift in the decision boundary. Thus, the underlying principle of double-black watermarking is that a model's decision boundary could serve as an inherent fingerprint for watermarking. Our approach captures the decision boundary by generating a limited number of encysted sample fingerprints, which are a set of naturally transformed and augmented inputs enclosed around the model's decision boundary in order to capture the inherent fingerprints of the model. We evaluated our watermarking approach against a variety of model integrity attacks and model compression attacks.

TSM: Measuring the Enticement of Honeyfiles with Natural Language Processing

Honeyfile deployment is a useful breach detection method in cyber deception that can also inform defenders about the intent and interests of intruders and malicious insiders. A key property of a honeyfile, enticement, is the extent to which the file can attract an intruder to interact with it. We introduce a novel metric, Topic Semantic Matching (TSM), which uses topic modelling to represent files in the repository and semantic matching in an embedding vector space to compare honeyfile text and topic words robustly. We also present a honeyfile corpus created with different Natural Language Processing (NLP) methods. Experiments show that TSM is effective in inter-corpus comparisons and is a promising tool to measure the enticement of honeyfiles. TSM is the first measure to use NLP techniques to quantify the enticement of honeyfile content that compares the essential topical content of local contexts to honeyfiles and is robust to paraphrasing.

Can pre-trained Transformers be used in detecting complex sensitive sentences? -- A Monsanto case study

Each and every organisation releases information in a variety of forms ranging from annual reports to legal proceedings. Such documents may contain sensitive information and releasing them openly may lead to the leakage of confidential information. Detection of sentences that contain sensitive information in documents can help organisations prevent the leakage of valuable confidential information. This is especially challenging when such sentences contain a substantial amount of information or are paraphrased versions of known sensitive content. Current approaches to sensitive information detection in such complex settings are based on keyword-based approaches or standard machine learning models. In this paper, we wish to explore whether pre-trained transformer models are well suited to detect complex sensitive information. Pre-trained transformers are typically trained on an enormous amount of text and therefore readily learn grammar, structure and other linguistic features, making them particularly attractive for this task. Through our experiments on the Monsanto trial data set, we observe that the fine-tuned Bidirectional Encoder Representations from Transformers (BERT) transformer model performs better than traditional models. We experimented with four different categories of documents in the Monsanto dataset and observed that BERT achieves better F2 scores by 24.13\% to 65.79\% for GHOST, 30.14\% to 54.88\% for TOXIC, 39.22\% for CHEMI, 53.57\% for REGUL compared to existing sensitive information detection models.