Sheng Chen, Tang Zhe, Weixing Zhang, Fei Yang, Yuanyuan. Wang, Tianlin Li, Yang Liu. Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers). 2026.

Recently, state-of-the-art stereo-matching networks trained on large-scale synthetic data have shown remarkable performance. However, their capacity to extrapolate effectively to unseen real-world data,i.e.different domains, remains a challenge. The major difficulty resides in the unforeseeable domain gap when generalizing from synthetic data to real-world data. In this paper, we introduceADASM, an approach using adversarial domain alignment, designed to enhance the robustness and generalization of stereo-matching networks. It mainly consists of two modules: an end-to-end robustness optimizer and a domain-invariant feature learner. First, we adapt adversarial training into the stereo-matching task to reduce models' sensitivity to the perturbation in real-world samples. By introducing worst cases into the training space, we take unseen data into account and achieve robust disparity estimation for the end-to-end model. Then, via simulating the real-world noise with gradient-based perturbation, we construct a fictitious domain, which is taken as a referential distribution of the real-world noisy data, for further domain alignment. Specifically, we propose to utilize Maximum Mean Discrepancy to realize domain regularization between the original domain and the fictitious one. Finally, we fuse all aforementioned objectives and propose a unified, simple but effective loss function that can be adapted toallstereo-matching networks. The extensive experiments show that our method achieves a superior disparity estimation performance on various real-world benchmarks, including KITTI, Middlebury, and DrivingStereo. More importantly,ADASMobtains competitive or even better performance than the fine-tuning strategy, revealing its fine-tuning-free character.

Guided image synthesis methods, like SDEdit based on the diffusion model, excel at creating realistic images from user inputs such as stroke paintings. However, existing efforts mainly focus on image quality, often overlooking a key point: the diffusion model represents a data distribution, not individual images. This introduces a low but critical chance of generating images that contradict user intentions, raising ethical concerns. For example, a user inputting a stroke painting with female characteristics might, with some probability, get male faces from SDEdit. To expose this potential vulnerability, we propose the Targeted Attribute Generative Attack (TAGA), whose objective is to force SDEdit to generate data distributions aligned with a specified attribute (i.e.,targeted attribute like male), without changing the attribute of the input image. Empirical studies reveal that traditional adversarial noise struggles to achieve TAGA, while natural perturbations such as exposure and motion blur can easily influence attributes of the generated images. Inspired by the observation, we design attack methodFOOLSDEDITto achieve effective TAGA against SDEdit. It aims to search for an optimized strategy to execute attacks within a weighted graph-based attack architecture, which is formulated to model diverse strategies derived from both exposure and motion blur perturbations. Comprehensive experiments on two commonly used datasets and three social attributes present thatFOOLSDEDITforces SDEdit to generate targeted attribute-aware distributions, achieving significantly more effective TAGA than the baselines. We also validated empirically thatFOOLSDEDITcould induce bias in downstream tasks of SDEdit which rely on the generated data under attack. Our work reveals critical vulnerabilities in diffusion-based image generation models and paves the way for future research on model auditing and bias mitigation.

The systems and software powered by Large Language Models (LLMs) and Multi-Modal Large Language Models (MLLMs) have played a critical role in numerous scenarios. However, current LLM systems are vulnerable to prompt-based attacks, with jailbreaking attacks enabling the LLM system to generate harmful content, while hijacking attacks manipulate the LLM system to perform attacker-desired tasks, underscoring the necessity for detection tools. Unfortunately, existing detecting approaches are usually tailored to specific attacks, resulting in poor generalization in detecting various attacks across different modalities. To address it, we propose JailGuard , a universal detection framework deployed on top of LLM systems for prompt-based attacks across text and image modalities. JailGuard operates on the principle that attacks are inherently less robust than benign ones. Specifically, JailGuard mutates untrusted inputs to generate variants and leverages the discrepancy of the variants’ responses on the target model to distinguish attack samples from benign samples. We implement 18 mutators for text and image inputs and design a mutator combination policy to further improve detection generalization. The evaluation on the dataset containing 15 known attack types suggests that JailGuard achieves the best detection accuracy of 86.14%/82.90% on text and image inputs, outperforming state-of-the-art methods by 11.81–25.73% and 12.20–21.40%.

Deep Neural Networks (DNNs), extensively applied across diverse disciplines, are characterized by their integrated and monolithic architectures, setting them apart from conventional software systems. This architectural difference introduces particular challenges to maintenance tasks, such as model restructure (e.g., model compression), re-adaptation (e.g., fitting new samples), and incremental development (e.g., continual knowledge accumulation). Prior research addresses these challenges by identifying task-critical neuron layers and dividing neural networks into semantically similar sequential modules. However, such layer-level approaches fail to precisely identify and manipulate neuron-level semantic components, restricting their applicability to finer-grained model maintenance tasks. In this work, we implement NeuSemSlice, a novel framework that introduces the semantic slicing technique to effectively identify critical neuron-level semantic components in DNN models for semantic-aware model maintenance tasks. Specifically, semantic slicing identifies, categorizes, and merges critical neurons across different categories and layers according to their semantic similarity, enabling their flexibility and effectiveness in the subsequent tasks. For semantic-aware model maintenance tasks, we provide a series of novel strategies based on semantic slicing to enhance NeuSemSlice. They include semantic components (i.e., critical neurons) preservation for model restructure, critical neuron tuning for model re-adaptation, and non-critical neuron training for model incremental development. A thorough evaluation has demonstrated that NeuSemSlice significantly outperforms baselines in all three tasks.

In recent years, Text-to-Image (T2I) models have garnered significant attention due to their remarkable advancements. However, security concerns have emerged due to their potential to generate inappropriate or Not-Safe-For-Work (NSFW) images. In this paper, inspired by the observation that texts with different semantics can lead to similar human perceptions, we propose an LLM-driven perception-guided jailbreak method, termed PGJ. It is a black-box jailbreak method that requires no specific T2I model (model-free) and generates highly natural attack prompts. Specifically, we propose identifying a safe phrase that is similar in human perception yet inconsistent in text semantics with the target unsafe word and using it as a substitution. The experiments conducted on six open-source models and commercial online services with thousands of prompts have verified the effectiveness of PGJ.

Segmenting masticatory muscles from CT scans remains a challenging task due to intertwined tissues and image artifacts. While large vision foundation models (FMs) have achieved notable success in medical image segmentation, they typically depend on extensive and high-quality annotated datasets for fine-tuning or adapter training. In this paper, we introduce a novel FM-based pseudo-labeling framework for segmenting masticatory muscles from CT scans without the need for manual pixel-level annotations. Our method employs an adaptive pseudolabeling strategy that integrates FM-generated labels with selftraining. By leveraging the robustness of self-training to noisy data, the framework improves the reliability of pseudo-labels and helps differentiate closely intertwined muscle structures. To further enhance segmentation performance, we incorporate a structure-aware enhancement module that combines contrastive learning and the consistency regularization of semantic similarity relationships. This reinforces patch-level feature embeddings and improves semantic correlation consistency in label inference. Our approach supports simultaneous segmentation of multi-category muscles and achieves reliable contour delineation from adjacent tissues. Experimental results demonstrate that our approach outperforms compared state-of-the-art methods in masticatory muscle segmentation. The source code is available at http-s://anonymous.4open.science/r/pl_fuse_bba-895C/.

Task-specific fine-tuning is essential for the deployment of large language models (LLMs), but it requires significant computational resources and time. Existing solutions have proposed coreset selection methods to improve data efficiency and reduce model training overhead, but they still have limitations: ❶ Overlooking valuable samples at high pruning rates, which degrades the coreset’s performance. ❷ Requiring high time overhead during coreset selection to fine-tune and evaluate the target LLM. In this paper, we introduce STAFF, a speculative coreset selection method. STAFF leverages a small model from the same family as the target LLM to efficiently estimate data scores and then verifies the scores on the target LLM to accurately identify and allocate more selection budget to important regions while maintaining coverage of easy regions. We evaluate STAFF on three LLMs and three downstream tasks and show that STAFF improves the performance of SOTA methods by up to 54.3% and reduces selection overhead by up to 70.5% at different pruning rates. Furthermore, we observe that the coreset selected by STAFF at low pruning rates (i.e., 20%) can even obtain better fine-tuning performance than the full dataset.

Recent studies have raised significant concerns regarding the vulnerability of Large Vision Language Models (LVLMs) to maliciously injected or perturbed input images, which can mislead their responses. Existing defense methods show that such vision attacks are sensitive to image modifications especially cropping, using majority voting across responses of modified images as corrected responses. However, these modifications often result in partial images and distort the semantics, which reduces response quality on clean images after voting. Instead of directly using responses from partial images for voting, we investigate using them to supervise (guide) the LVLM’s responses to the original images at inference time. We propose a black-box, training-free method called DPS (Defense through Partial-Perception Supervision). In this approach, the model is prompted using the responses generated by a model that perceives only a partial image. With DPS, the model can adjust its response based on partial image understanding when under attack, while confidently maintaining its original response for clean input. Empirical experiments show our method outperforms the baseline, cutting the average attack success rate by 76.3% across six datasets on three popular models.

Deep Learning (DL) has achieved significant success in socially critical decision-making applications but often exhibits unfair behaviors, raising social concerns. Among these unfair behaviors, individual discrimination-examining inequalities between instance pairs with identical profiles differing only in sensitive attributes such as gender, race, and age-is extremely socially impactful. Existing methods have made significant and commendable efforts in testing individual discrimination before deployment. However, their efficiency and effectiveness remain limited, particularly when evaluating relatively fairer models. It remains unclear which phase of the existing testing framework (global or local) is the primary bottleneck limiting performance. Facing the above issues, we first identify that enhancing the global phase consistently improves overall testing effectiveness compared to enhancing the local phase. This motivates us to propose Genetic-Random Fairness Testing (GRFT), an effective and efficient method. In the global phase, we use a genetic algorithm to guide the search for more global discriminatory instances. In the local phase, we apply a light random search to explore the neighbors of these instances, avoiding time-consuming computations. Additionally, based on the fitness score, we also propose a straightforward yet effective repair approach. For a thorough evaluation, we conduct extensive experiments involving 6 testing methods, 5 datasets, 261 models (including 5 naively trained, 64 repaired, and 192 quantized for on-device deployment), and sixteen combinations of sensitive attributes, showing the superior performance of GRFT and our repair method.

Pre-trained large deep learning models are now serving as the dominant component for downstream middleware users and have revolutionized the learning paradigm, replacing the traditional approach of training from scratch locally. To reduce development costs, developers often integrate third-party pre-trained deep neural networks (DNNs) into their intelligent software systems. However, utilizing untrusted DNNs presents significant security risks, as these models may contain intentional backdoor defects resulting from the black-box training process. These backdoor defects can be activated by hidden triggers, allowing attackers to maliciously control the model and compromise the overall reliability of the intelligent software. To ensure the safe adoption of DNNs in critical software systems, it is crucial to establish a backdoor defect database for localization studies. This paper addresses this research gap by introducing BDefects4NN, the first backdoor defect database, which provides labeled backdoor-defected DNNs at the neuron granularity and enables controlled localization studies of defect root causes. In BDefects$4 N N$, we define three defect injection rules and employ four representative backdoor attacks across four popular network architectures and three widely adopted datasets, yielding a comprehensive database of$\mathbf{1, 6 5 4}$backdoor-defected DNNs with four defect quantities and varying infected neurons. Based on BDefects4NN, we conduct extensive experiments on evaluating six fault localization criteria and two defect repair techniques, which show limited effectiveness for backdoor defects. Additionally, we investigate backdoor-defected models in practical scenarios, specifically in lane detection for autonomous driving and large language models (LLMs), revealing potential threats and highlighting current limitations in precise defect localization. This paper aims to raise awareness of the threats brought by backdoor defects in our community and inspire future advancements in fault localization methods.

Large language models (LLMs) have revolutionized artificial intelligence, but their increasing deployment across critical domains has raised concerns about their abnormal behaviors when faced with malicious attacks. Such vulnerability alerts the widespread inadequacy of pre-release testing. In this paper, we conduct a comprehensive empirical study to evaluate the effectiveness of traditional coverage criteria in identifying such inadequacies, exemplified by the significant security concern of jailbreak attacks. Our study begins with a clustering analysis of the hidden states of LLMs, revealing that the embedded characteristics effectively distinguish between different query types. We then systematically evaluate the performance of these criteria across three key dimensions: criterion level, layer level, and token level. Our research uncovers significant differences in neuron coverage when LLMs process normal versus jailbreak queries, aligning with our clustering experiments. Leveraging these findings, we propose three practical applications of coverage criteria in the context of LLM security testing. Specifically, we develop a realtime jailbreak detection mechanism that achieves high accuracy (93.61 % on average) in classifying queries as normal or jailbreak. Furthermore, we explore the use of coverage levels to prioritize test cases, improving testing efficiency by focusing on high-risk interactions and removing redundant tests. Lastly, we introduce a coverage-guided approach for generating jailbreak attack examples, enabling systematic refinement of prompts to uncover vulnerabilities. This study improves our understanding of LLM security testing, enhances their safety, and provides a foundation for developing more robust AI applications.

Recent code large language models (LLMs) have shown promising performance in generating standalone functions. However, they face limitations in repository-level code generation due to their lack of awareness of repository-level dependencies ( e.g., user-defined attributes), resulting in dependency errors such as undefined-variable and no-member errors. In this work, we introduce ToolGen , an approach that integrates autocompletion tools into the code LLM generation process to address these dependencies. ToolGen comprises two main phases: Trigger Insertion and Model Fine-tuning (Offline), and Tool-integrated Code Generation (Online). During the offline phase, ToolGen augments functions within a given code corpus with a special mark token, indicating positions to trigger autocompletion tools. These augmented functions, along with their corresponding descriptions, are then used to fine-tune a selected code LLM. In the online phase, ToolGen iteratively generates functions by predicting tokens step-by-step using the fine-tuned LLM. Whenever a mark token is encountered, ToolGen invokes the autocompletion tool to suggest code completions and selects the most appropriate one through constrained greedy search. We conduct comprehensive experiments to evaluate ToolGen ’s effectiveness in repository-level code generation across three distinct code LLMs: CodeGPT, CodeT5, and CodeLlama. To facilitate this evaluation, we create a benchmark comprising 671 real-world code repositories and introduce two new dependency-based metrics: Dependency Coverage and Static Validity Rate . The results demonstrate that ToolGen significantly improves Dependency Coverage by 31.4% to 39.1% and Static Validity Rate by 44.9% to 57.7% across the three LLMs, while maintaining competitive or improved performance in widely recognized similarity metrics such as BLEU-4, CodeBLEU, Edit Similarity, and Exact Match. On the CoderEval dataset, ToolGen achieves improvements of 40.0% and 25.0% in test pass rate (Pass@1) for CodeT5 and CodeLlama, respectively, while maintaining the same pass rate for CodeGPT. ToolGen also demonstrates high efficiency in repository-level code generation, with latency ranging from 0.63 to 2.34 seconds for generating each function. Furthermore, our generalizability evaluation confirms ToolGen ’s consistent performance when applied to diverse code LLMs, encompassing various model architectures and scales.

Although recent personalization methods have democratized high-resolution image synthesis by enabling swift concept acquisition with minimal examples and lightweight computation, they also present an exploitable avenue for highly accessible backdoor attacks. This paper investigates a critical and unexplored aspect of text-to-image (T2I) diffusion models - their potential vulnerability to backdoor attacks via personalization. By studying the prompt processing of popular personalization methods (epitomized by Textual Inversion and DreamBooth), we have devised dedicated personalization-based backdoor attacks according to the different ways of dealing with unseen tokens and divide them into two families: nouveau-token and legacy-token backdoor attacks. In comparison to conventional backdoor attacks involving the fine-tuning of the entire text-to-image diffusion model, our proposed personalization-based backdoor attack method can facilitate more tailored, efficient, and few-shot attacks. Through comprehensive empirical study, we endorse the utilization of the nouveau-token backdoor attack due to its impressive effectiveness, stealthiness, and integrity, markedly outperforming the legacy-token backdoor attack.

Although Federated Learning (FL) enables collaborative model training without sharing the raw data of clients, it encounters low-performance problems caused by various heterogeneous scenarios. Due to the limitation of dispatching the same global model to clients for local training, traditional Federated Average (FedAvg)-based FL models face the problem of easily getting stuck into a sharp solution, which results in training a low-performance global model. To address this problem, this paper presents a novel FL approach named FedMut, which mutates the global model according to the gradient change to generate several intermediate models for the next round of training. Each intermediate model will be dispatched to a client for local training. Eventually, the global model converges into a flat area within the range of mutated models and has a well-generalization compared with the global model trained by FedAvg. Experimental results on well-known datasets demonstrate the effectiveness of our FedMut approach in various data heterogeneity scenarios.

Deep learning has introduced significant improvements in many software analysis tasks. Although the Large Language Models (LLMs) based neural code models demonstrate commendable performance when trained and tested within the intra-project independent and identically distributed (IID) setting, they often struggle to generalize effectively to real-world inter-project out-of-distribution (OOD) data. In this work, we show that this phenomenon is caused by the heavy reliance on project-specific shortcuts for prediction instead of ground-truth evidence. We propose a Cond-Idf measurement to interpret this behavior, which quantifies the relatedness of a token with a label and its project-specificness. The strong correlation between model behavior and the proposed measurement indicates that without proper regularization, models tend to leverage spurious statistical cues for prediction. Equipped with these observations, we propose a novel bias mitigation mechanism that regularizes the model’s learning behavior by leveraging latent logic relations among samples. Experimental results on two representative program analysis tasks indicate that our mitigation framework can improve both inter-project OOD generalization and adversarial robustness, while not sacrificing accuracy on intra-project IID data.

We introduce a novel approach to counter adversarial attacks, namely, image resampling. Image resampling transforms a discrete image into a new one, simulating the process of scene recapturing or rerendering as specified by a geometrical transformation. The underlying rationale behind our idea is that image resampling can alleviate the influence of adversarial perturbations while preserving essential semantic information, thereby conferring an inherent advantage in defending against adversarial attacks. To validate this concept, we present a comprehensive study on leveraging image resampling to defend against adversarial attacks. We have developed basic resampling methods that employ interpolation strategies and coordinate shifting magnitudes. Our analysis reveals that these basic methods can partially mitigate adversarial attacks. However, they come with apparent limitations: the accuracy of clean images noticeably decreases, while the improvement in accuracy on adversarial examples is not substantial.We propose implicit representation-driven image resampling (IRAD) to overcome these limitations. First, we construct an implicit continuous representation that enables us to represent any input image within a continuous coordinate space. Second, we introduce SampleNet, which automatically generates pixel-wise shifts for resampling in response to different inputs. Furthermore, we can extend our approach to the state-of-the-art diffusion-based method, accelerating it with fewer time steps while preserving its defense capability. Extensive experiments demonstrate that our method significantly enhances the adversarial robustness of diverse deep models against various attacks while maintaining high accuracy on clean images.

Mainstream backdoor attack methods typically demand substantial tuning data for poisoning, limiting their practicality and potentially degrading the overall performance when applied to Large Language Models (LLMs). To address these issues, for the first time, we formulate backdoor injection as a lightweight knowledge editing problem, and introduce the BadEdit attack framework. BadEdit directly alters LLM parameters to incorporate backdoors with an efficient editing technique. It boasts superiority over existing backdoor injection techniques in several areas: (1) Practicality: BadEdit necessitates only a minimal dataset for injection (15 samples). (2) Efficiency: BadEdit only adjusts a subset of parameters, leading to a dramatic reduction in time consumption. (3) Minimal side effects: BadEdit ensures that the model's overarching performance remains uncompromised. (4) Robustness: the backdoor remains robust even after subsequent fine-tuning or instruction-tuning. Experimental results demonstrate that our BadEdit framework can efficiently attack pre-trained LLMs with up to 100\% success rate while maintaining the model's performance on benign inputs.

Reasoning is a fundamental ability towards artificial general intelligence (AGI). Fueled by the success of deep learning, the neural logic machines models (NLMs) have introduced novel neural-symbolic structures and demonstrate great performance and generalization on reasoning and decision-making tasks. However, the original training approaches of the NLMs are still far from perfect, the models would repeat similar mistakes during the training process which leads to sub-optimal performance. To mitigate this issue, we present a novel framework named Failure Reflection Guided Regularizer (FRGR). FRGR first dynamically identifies and summarizes the root cause if the model repeats similar mistakes during training. Then it penalizes the model if it makes similar mistakes in future training iterations. In this way, the model is expected to avoid repeating errors of similar root causes and converge faster to a better-performed optimum. Experimental results on multiple relational reasoning and decision-making tasks demonstrate the effectiveness of FRGR in improving performance, generalization, training efficiency, and data efficiency.

Deep Neural Networks (DNNs), an emerging software technology, have achieved impressive results in a variety of fields. However, the discriminatory behaviors towards certain groups (a.k.a. unfairness) of DNN models increasingly become a social concern, especially in high-stake applications such as loan approval and criminal risk assessment. Although there has been a number of works to improve model fairness, most of them adopt an adversary to either expand the model architecture or augment training data, which introduces excessive computational overhead. Recent work diagnoses responsible unfair neurons first and fixes them with selective retraining. Unfortunately, existing diagnosis process is time-consuming due to multi-step training sample analysis, and selective retraining may cause a performance bottleneck due to indirectly adjusting unfair neurons on biased samples. In this paper, we propose Responsible UNfair NEuron Repair (RUNNER) that improves existing works in three key aspects: (1) efficiency: we design the Importance-based Neuron Diagnosis that identifies responsible unfair neurons in one step with a novel importance criterion of neurons; (2) effectiveness: we design the Neuron Stabilizing Retraining by adding a loss term that measures the activation distance of responsible unfair neurons from different subgroups in all sources; (3) generalization: we investigate the effectiveness on both structured tabular data and large-scale unstructured image data, which is often ignored in prior studies. Our extensive experiments across 5 datasets show that RUUNER can effectively and efficiently diagnose and repair the DNNs regarding unfairness. On average, our approach significantly reduces computing overhead from 341.7s to 29.65s, and achieves improved fairness up to 79.3%. Besides, RUNNER also keeps state-of-the-art results on the unstructured dataset.

Software vulnerabilities pose serious threats to the security of modern software systems. Deep Learning-based Automated Vulnerability Repair (AVR) has gained attention as a potential solution to accelerate the remediation of vulnerabilities. However, recent studies indicate that existing AVR approaches often only generate patches, which may not align with developers' current repair practices or expectations. In this paper, we introduce VulAdvisor, an automated approach that generates natural language suggestions to guide developers or AVR tools in repairing vulnerabilities. VulAdvisor comprises two main components: oracle extraction and suggestion learning. To address the challenge of limited historical data, we propose an oracle extraction method facilitating ChatGPT to construct a comprehensive and high-quality dataset. For suggestion learning, we take the supervised fine-tuning CodeT5 model as the basis, integrating local context into Multi-Head Attention and introducing a repair action loss, to improve the relevance and meaningfulness of the generated suggestions. Extensive experiments on a large-scale dataset from real-world C/C++ projects demonstrate the effectiveness of VulAdvisor, surpassing several alternatives in terms of both lexical and semantic metrics. Moreover, we show that the generated suggestions enhance the patch generation capabilities of existing AVR tools. Human evaluations further validate the quality and utility of VulAdvisor's suggestions, confirming their potential to improve software vulnerability repair practices.

The advancement of Machine Learning has enabled the widespread deployment of Machine Learning as a Service (MLaaS) applications. However, the untrustworthy nature of third-party ML services poses backdoor threats. Existing defenses in MLaaS are limited by their reliance on training samples or white-box model analysis, highlighting the need for a black-box backdoor purification method. In our paper, we attempt to use diffusion models for purification by introducing noise in a forward diffusion process to destroy backdoors and recover clean samples through a reverse generative process. However, since a higher noise also destroys the semantics of the original samples, it still results in a low restoration performance. To investigate the effectiveness of noise in eliminating different types of backdoors, we conducted a preliminary study, which demonstrates that backdoors with low visibility can be easily destroyed by lightweight noise and those with high visibility need to be destroyed by high noise but can be easily detected. Based on the study, we propose SampDetox, which strategically combines lightweight and high noise. SampDetox applies weak noise to eliminate low-visibility backdoors and compares the structural similarity between the recovered and original samples to localize high-visibility backdoors. Intensive noise is then applied to these localized areas, destroying the high-visibility backdoors while preserving global semantic information. As a result, detoxified samples can be used for inference, even by poisoned models. Comprehensive experiments demonstrate the effectiveness of SampDetox in defending against various state-of-the-art backdoor attacks.

Federated learning (FL) as a promising distributed machine learning paradigm has been widely adopted in Artificial Intelligence of Things (AIoT) applications. However, the efficiency and inference capability of FL is seriously limited due to the presence of stragglers and data imbalance across massive AIoT devices, respectively. To address the above challenges, we present a novel asynchronous FL approach named CaBaFL, which includes a hierarchical cache-based aggregation mechanism and a feature balance-guided device selection strategy. CaBaFL maintains multiple intermediate models simultaneously for local training. The hierarchical cache-based aggregation mechanism enables each intermediate model to be trained on multiple devices to align the training time and mitigate the straggler issue. In specific, each intermediate model is stored in a low-level cache for local training and when it is trained by sufficient local devices, it will be stored in a high-level cache for aggregation. To address the problem of imbalanced data, the feature balance-guided device selection strategy in CaBaFL adopts the activation distribution as a metric, which enables each intermediate model to be trained across devices with totally balanced data distributions before aggregation. Experimental results show that compared to the state-of-the-art FL methods, CaBaFL achieves up to 9.26X training acceleration and 19.71% accuracy improvements.

The abuse of deepfake techniques has raised serious concerns about social security and ethical problems, which motivates the development of deepfake detection. However, without fully addressing the domain gap issue, existing deepfake detection methods still show weak generalization ability among datasets belonging to different domains with domain-specific characteristics like identities and generation methods, limiting their practical applications. In this paper, we propose theInvariant Domain-oriented Deepfake Detection method (ID$_{3}$), which improves the generalization of deepfake detection on multiple domains through invariant risk minimization, a novel learning paradigm that addresses the domain gap problem by jointly training a purified invariant predictor and learning an aligned invariant representation. To train a purified invariant predictor, we design theDomain Refinement Data Augmentationstrategy with self-face-swapping and region-erasing approaches, which suppresses domain-specific features and encourages the models to focus on critical domain-invariant characteristics. To learn an aligned invariant representation, we propose theDomain Calibration Batch Normalizationapproach with multiple BN branches, which normalizes input features from different domains into aligned representations during both training and testing. Extensive experiments on multiple datasets demonstrate that our framework can boost the deepfake detection generalization ability and outperform other baselines by large margins. Our codes can be found here

Deep Neural Networks (DNNs) have achieved tremendous success in many applications, while it has been demonstrated that DNNs can exhibit some undesirable behaviors on concerns such as robustness, privacy, and other trustworthiness issues. Among them, fairness (i.e., non-discrimination) is one important property, especially when they are applied to some sensitive applications (e.g., finance and employment). However, DNNs easily learn spurious correlations between protected attributes (e.g., age, gender, race) and the classification task and develop discriminatory behaviors if the training data is imbalanced. Such discriminatory decisions in sensitive applications would introduce severe social impacts. To expose potential discrimination problems in DNNs before putting them in use, some testing techniques have been proposed to identify the discriminatory instances (i.e., instances that show defined discrimination 1 ). However, how to repair DNNs after detecting such discrimination is still challenging. Existing techniques mainly rely on retraining on a large number of discriminatory instances generated by testing methods, which requires huge time overhead and makes the repairing inefficient. In this work, we propose the method Faire to effectively and efficiently repair the fairness issues of DNNs, without using additional data (e.g., discriminatory instances). Our basic idea is inspired by the traditional program repair method that synthesizes proper condition checking. To repair traditional programs, a typical method is to localize the program defects and repair the program logic by adding condition checking. Similarly, for DNNs, we try to understand the unfair logic and reformulate it with well-designed condition checking. In this article, we synthesize the condition that can reduce the effect of features relevant to the protected attributes in the DNN. Specifically, we first perform the neuron-based analysis and check the functionalities of neurons to identify neurons whose outputs could be regarded as features relevant to protected attributes and original tasks. Then a new condition layer is added after each hidden layer to penalize neurons that are accountable for the protected features (i.e., intermediate features relevant to protected attributes) and promote neurons that are accountable for the non-protected features (i.e., intermediate features relevant to original tasks). In sum, the repair rate 2 of Faire reaches up to more than 99%, which outperforms other methods, and the whole repairing process only takes no more than 340 s. The evaluation results demonstrate that our approach can effectively and efficiently repair the individual discriminatory instances of the target model.

Deep neural networks (DNNs) have made significant progress, but often suffer from fairness issues, as deep models typically show distinct accuracy differences among certain subgroups (e.g., males and females). Existing research addresses this critical issue by employing fairness-aware loss functions to constrain the last-layer outputs and directly regularize DNNs. Although the fairness of DNNs is improved, it is unclear how the trained network makes a fair prediction, which limits future fairness improvements. In this paper, we investigate fairness from the perspective of decision rationale and define the parameter parity score to characterize the fair decision process of networks by analyzing neuron influence in various subgroups. Extensive empirical studies show that the unfair issue could arise from the unaligned decision rationales of subgroups. Existing fairness regularization terms fail to achieve decision rationale alignment because they only constrain last-layer outputs while ignoring intermediate neuron alignment. To address the issue, we formulate the fairness as a new task, i.e., decision rationale alignment that requires DNNs’ neurons to have consistent responses on subgroups at both intermediate processes and the final prediction. To make this idea practical during optimization, we relax the naive objective function and propose gradient-guided parity alignment, which encourages gradient-weighted consistency of neurons across subgroups. Extensive experiments on a variety of datasets show that our method can significantly enhance fairness while sustaining a high level of accuracy and outperforming other approaches by a wide margin.

Fairness issues in Deep Learning models have recently received increasing attention due to their significant societal impact. Although methods for mitigating unfairness are constantly proposed, little research has been conducted to understand how discrimination and bias develop during the standard training process. In this study, we propose analyzing the contribution of each subgroup (i.e., a group of data with the same sensitive attribute) in the training process to understand the cause of such bias development process. We propose a gradient-based metric to assess training subgroup contribution disparity, showing that unequal contributions from different subgroups are one source of such unfairness. One way to balance the contribution of each subgroup is through oversampling, which ensures that an equal number of samples are drawn from each subgroup during each training iteration. However, we have found that even with a balanced number of samples, the contribution of each group remains unequal, resulting in unfairness under the oversampling strategy. To address the above issues, we propose an easy but effective group contribution matching (GCM) method to match the contribution of each subgroup. Our experiments show that our GCM effectively improves fairness and outperforms other methods significantly.

Machine learning (ML) systems have achieved remarkable performance across a wide area of applications. However, they frequently exhibit unfair behaviors in sensitive application domains (e.g., employment and loan), raising severe fairness concerns. To evaluate and test fairness, engineers often generate individual discriminatory instances to expose unfair behaviors before model deployment. However, existing baselines ignore the naturalness of generation and produce instances that deviate from the real data distribution, which may fail to reveal the actual model fairness since these unnatural discriminatory instances are unlikely to appear in practice. To address the problem, this paper proposes a framework named Latent Imitator (LIMI) to generate more natural individual discriminatory instances with the help of a generative adversarial network (GAN), where we imitate the decision boundary of the target model in the semantic latent space of GAN and further samples latent instances on it. Specifically, we first derive a surrogate linear boundary to coarsely approximate the decision boundary of the target model, which reflects the nature of the original data distribution. Subsequently, to obtain more natural instances, we manipulate random latent vectors to the surrogate boundary with a one-step movement, and further conduct vector calculation to probe two potential discriminatory candidates that may be more closely located in the real decision boundary. Extensive experiments on various datasets demonstrate that our LIMI outperforms other baselines largely in effectiveness (×9.42 instances), efficiency (×8.71 speeds), and naturalness (+19.65%) on average. In addition, we empirically demonstrate that retraining on test samples generated by our approach can lead to improvements in both individual fairness (45.67% on IFr and 32.81% on IFo) and group fairness (9.86% on SPD and 28.38% on AOD). Our codes can be found on our website.

Automatically discovering software vulnerabilities is a long-standing pursuit for software developers and security analysts. Since detection tools usually provide limited information for vulnerability inspection, recent work turns the attention to identify fine-grained vulnerabilities, i.e., vulnerable statements. However, existing work for vulnerability localization struggles to capture long-range and integral dependency information due to the bottleneck of Graph Neural Networks (GNNs). Moreover, little research has been done to help developers understand detected vulnerabilities, leaving vulnerability diagnosis a challenging task. In this paper, we propose VulTeller, a deep learning-based approach that can automatically locate vulnerable statements in a function and more importantly, can describe the vulnerability. Our approach focuses on extracting precise control and data dependencies in the code, achieved through modeling control flow paths and employing taint analysis. We design a novel neural model that encodes the control flows and taint flows which reside in the control flow paths, and decodes them via node classification and an attentional decoder for the two tasks respectively. We conduct extensive experiments with real-world vulnerabilities to evaluate the proposed approach. The evaluation results, including quantitative measurement and human evaluation, demonstrate that our approach is highly effective and outperforms state-of-the-art approaches. Our work for the first time formulates the problem of vulnerability description generation, and makes one step further towards automated vulnerability diagnosis.

Deep learning has recently been widely applied to many applications across different domains, e.g., image classification and audio recognition. However, the quality of Deep Neural Networks (DNNs) still raises concerns in the practical operational environment, which calls for systematic testing, especially in safety-critical scenarios. Inspired by software testing, a number of structural coverage criteria are designed and proposed to measure the test adequacy of DNNs. However, due to the blackbox nature of DNN, the existing structural coverage criteria are difficult to interpret, making it hard to understand the underlying principles of these criteria. The relationship between the structural coverage and the decision logic of DNNs is unknown. Moreover, recent studies have further revealed the non-existence of correlation between the structural coverage and DNN defect detection, which further posts concerns on what a suitable DNN testing criterion should be. In this article, we propose the interpretable coverage criteria through constructing the decision structure of a DNN. Mirroring the control flow graph of the traditional program, we first extract a decision graph from a DNN based on its interpretation, where a path of the decision graph represents a decision logic of the DNN. Based on the control flow and data flow of the decision graph, we propose two variants of path coverage to measure the adequacy of the test cases in exercising the decision logic. The higher the path coverage, the more diverse decision logic the DNN is expected to be explored. Our large-scale evaluation results demonstrate that: The path in the decision graph is effective in characterizing the decision of the DNN, and the proposed coverage criteria are also sensitive with errors, including natural errors and adversarial examples, and strongly correlate with the output impartiality.

Deep neural networks (DNNs) are vulnerable to adversarial examples which are generated by inputs with imperceptible perturbations. Understanding adversarial robustness of DNNs has become an important issue, which would for certain result in better practical deep learning applications. To address this issue, we try to explain adversarial robustness for deep models from a new perspective of critical attacking route, which is computed by a gradient-based influence propagation strategy. Similar to rumor spreading in social networks, we believe that adversarial noises are amplified and propagated through the critical attacking route. By exploiting neurons’ influences layer by layer, we compose the critical attacking route with neurons that make the highest contributions towards model decision. In this paper, we first draw the close connection between adversarial robustness and critical attacking route, as the route makes the most non-trivial contributions to model predictions in the adversarial setting. By constraining the propagation process and node behaviors on this route, we could weaken the noise propagation and improve model robustness. Also, we find that critical attacking neurons are useful to evaluate sample adversarial hardness that images with higher stimulus are easier to be perturbed into adversarial examples.

Deep neural networks (DNNs) are vulnerable to adversarial examples where inputs with imperceptible perturbations mislead DNNs to incorrect results. Despite the potential risk they bring, adversarial examples are also valuable for providing insights into the weakness and blind-spots of DNNs. Thus, the interpretability of a DNN in the adversarial setting aims to explain the rationale behind its decision-making process and makes deeper understanding which results in better practical applications. To address this issue, we try to explain adversarial robustness for deep models from a new perspective of neuron sensitivity which is measured by neuron behavior variation intensity against benign and adversarial examples. In this paper, we first draw the close connection between adversarial robustness and neuron sensitivities, as sensitive neurons make the most non-trivial contributions to model predictions in the adversarial setting. Based on that, we further propose to improve adversarial robustness by stabilizing the behaviors of sensitive neurons. Moreover, we demonstrate that state-of-the-art adversarial training methods improve model robustness by reducing neuron sensitivities, which in turn confirms the strong connections between adversarial robustness and neuron sensitivity. Extensive experiments on various datasets demonstrate that our algorithm effectively achieves excellent results. To the best of our knowledge, we are the first to study adversarial robustness using neuron sensitivities.

Cloud platforms are increasingly using containers for lightweight virtualization. Unlike full system virtual machines (VMs) that each runs its own operating system, containers share a stateful operating system to reduce their memory footprint and execution overheads. However, mainstream operating systems are currently limited in their ability to customize a container's memory management, since they lack the necessary abstractions and mechanisms to accurately track and isolate a container's memory footprint. We propose a new abstraction, called the Container-Level Address Space (CLAS), that provides a unified view of a container's memory across all of its constituent processes. We present the design of ContainerVisor, a per-container resource management system that leverages CLAS to provide customized memory management services. We describe a ContainerVisor prototype on Linux for running unmodified applications and demonstrate three proof-of-concept customized services, namely process-level memory limits and reservations, container-specific page replacement policies, and privacy-aware memory de-allocation. Our evaluations show that ContainerVisor can provide these customized services within reasonable overheads.

An efficient multi-threaded memory allocator has great impact on performance of applications with frequent memory allocation and deallocation operations. Currently, most popular memory allocators ignore the difference between thread local and shared memory, and manage them in a unified manner, which cannot make good use of the spatiotemporal locality of memory access. To solve this problem, this paper proposes a hybrid and lock-free multi-threaded memory allocator, named HMalloc. The allocator separates local memory from shared memory. There is no false sharing and lock contentions in local memory allocation and deallocation process. Moreover, coalescence-free is used to optimize this process. Further, a flag-based shared memory allocation and deallocation method is proposed to achieve lock-free shared memory management. Experimental results show that HMalloc can achieve significant performance improvement when compared with existing well-known memory allocators.

Summary Allocating appropriate resource for parallel and distributed simulation (PADS) applications in clouds is an intuitive way to improve their execution efficiency. However, the heterogeneity of virtual machine (VMs) in clouds with respect to both their computing power and network latency influences the execution efficiency of PADS applications on different combinations of VMs. Besides, frequent synchronization is one of the characteristics during the execution of PADS applications, which seriously challenges the prediction of the influence of VMs' computing power and network latency on their execution efficiency, and makes allocating appropriate VMs difficult as a result. This paper first proposes a revivification‐based prediction model (ERP), which revives the execution based on statistical data from actual execution of PADS applications to predict the running time of PADS applications on different combinations of VMs. Then, an ERP‐based Allocation algorithm, namely, ERPA, is raised to optimize VMs allocation to minimize the running time of PADS applications in clouds. A series of experiments are conducted to compare the proposed ERPA with three resource allocation algorithms, ie, Gang‐scheduling‐based, Makespan‐based, and Max‐Min‐based algorithms, and the experimental results demonstrate the advantage of ERPA in improving execution efficiency of PADS applications in clouds. In particular, for communication‐sensitive PADS applications, the advantage of ERPA is more significant.

In distributed simulation, communication based on publish/subscribe will generate large amount of irrelevant data transmissions, and thereby degrading the performance. To solve the problem, HLA standard defines data distribution management to filter unnecessary communication. Among several famous interest matching algorithms, the sort-based algorithm has been proven to be the most efficient method in most scenarios. However, the potential of existing sort-based algorithm has not been fully exploited, due to the overhead of sorting the bounds can be further reduced and a portion of unnecessary bit operations can be eliminated. In this paper, we propose a binary search enhanced sort-based interest matching algorithm (BSSIM). Based on a different sufficient and necessary condition to judge interval overlapping, the size of list to be sorted can be remarkably reduced. Moreover, unnecessary bit operations can be eliminated by binary searches. Experimental results show that BSSIM algorithm outperforms the sort-based algorithm, and approximately 64%-159% performance improvement can be achieved at different scenarios.

Electronic mail (email) is universally used by businesses, government agencies, and individual users. Out of necessity, users trust their email systems to keep their emails safe and secure. However, email systems are often complex and exhaustive testing is almost impossible for such systems. As a result, email systems often contain bugs and security vulnerabilities. In this paper, we analyze the security and usability of five popular public email systems. Our analysis shows that there are several security vulnerabilities in multiple sign-in and password composition and recovery policy of some of the email systems.

Virtual machine (VM) migration is a technique for transferring the execution state of a VM from one physical host to another. While VM migration is critical for load balancing, consolidation, and server maintenance in virtualized data centers, it can also increase security risks. During VM migration, an attacker with sufficient privileges can compromise a VM by modifying its memory contents during transit to subvert its applications or the guest operating system. One could maintain dedicated, and presumably more secure, control networks to carry the migration traffic, but at significant hardware and administrative complexity. Alternatively, one could encrypt the migration traffic, which eliminates the need for dedicated control networks, but might introduce performance overheads. To date, there has been no systematic study of how encryption affects VM migration, especially in high-bandwidth low-delay networks that are common within data centers. In this paper, we present a study of the impact of AES and 3DES encryption algorithms on two widely used live VM migration approaches - pre-copy and post-copy. Our key findings are as follows. The encryption algorithm used can have a significant impact on the total migration time. The impact of encryption on downtime varies with the type of the migration technique. The overhead of encryption also depends upon the relative speeds of source and target machines. Finally, an application's performance within a VM during encrypted migration varies with the type of the application and the migration mechanism.

Cloud computing systems routinely process users' confidential data, but the underlying virtualization software in use today is not constructed to minimize the exposure of such data. For instance, virtual machine (VM) checkpointing can drastically prolong the lifetime and vulnerability of confidential data without users' knowledge by storing such data as part of a persistent snapshot. A key requirement for minimizing the exposure of any data is the ability to cleanly isolate such data for either exclusion or processing. Traditional mechanisms for memory taint tracking are expensive whereas those for isolating application footprint in VM-based sandboxes are not transparent. In this paper, we propose a transparent and lightweight mechanism for isolating a confidential application's memory footprint in a VM. The key idea is for a parent VM to spawn a child VM, called a Privacy-preserving Virtual Machine (PPVM) within which the confidential application executes. Hypervisor features, such as VM checkpointing, that need to exclude the memory of a confidential application can safely ignore the child VM's memory footprint. Alternatively, features such as checkpoint encryption or malware tracking can operate only on the child VM's memory. We implement memory isolation for PPVM through a lightweight VM fork operation that uses copy-on-write to reduce the memory and filesystem overhead of the PPVM. Transparency is achieved through a confidential shell that allows the parent VM to spawn the confidential application in the PPVM and exercise control over it during runtime. We demonstrate the effectiveness of PPVM through its use with VM checkpointing, which can safely checkpoint the parent VM while excluding or encrypting the associated PPVM. We show that our PPVM implementation achieves effective memory isolation with low overheads on memory, CPU, and network performance.

Virtualization has been widely adopted in recent years in the cloud computing platform to improve server consolidation and reduce operating cost. Virtual Machine (VM) checkpointing refers to the act of saving a persistent snapshot (or checkpoint) of a VM's state at any instant. VM checkpointing can drastically prolong the lifetime and vulnerability of confidential or private user data in applications that execute within VMs. Simply encrypting the checkpoint does not reduce the lifetime of confidential data that should be quickly discarded after its use. In this paper, we present an application-level approach, called Privacy-preserving Checkpointing (PPC), which excludes confidential data from VM checkpoints, instead of encrypting such data. PPC enables an application programmer to register memory locations that represent the origins of confidential data. During the VM's execution, PPC performs information flow analysis to automatically track the propagation of confidential data through the application and various components of the VM, including the guest operating system. During VM checkpointing, the locations identified during the information flow analysis are excluded from the persistent checkpoint. We present the design and implementation of the PPC system in VirtualBox VMs running the commodity Linux operating system. We demonstrate the use of our system using the vim and gedit text editors. We also show that PPC introduces acceptable performance overhead.