Embedding Vulnerabilities

Large Language Models (LLMs), including Llama 2, Mistral, and Vicuna, are susceptible to a white-box adversarial attack that circumvents safety alignment mechanisms (such as RLHF). The vulnerability exists due to the models' susceptibility to intrinsic optimization of adversarial suffixes using Exponentiated Gradient Descent (EGD). Unlike previous methods that rely on inefficient discrete token searches (e.g., Greedy Coordinate Gradient) or standard projected gradient descent, this attack…

Retrieval-Augmented Generation (RAG) systems utilizing dense (e.g., BERT-based) or sparse (e.g., BM25) retrievers are vulnerable to black-box adversarial prompt injection attacks. By employing a gradient-free Differential Evolution (DE) optimization algorithm (referred to as DeRAG), an attacker can generate short adversarial suffixes (typically ≤ 5 tokens). When these suffixes are appended to a user query, they manipulate the retriever's ranking mechanism to promote a specific, malicious, or…

Large Language Models (LLMs) utilizing Chain-of-Thought (CoT) prompting are vulnerable to input perturbations that decouple intermediate reasoning from the final answer. An attacker can generate adversarial examples using gradient-based optimization (targeting specific loss functions that maximize reasoning divergence while minimizing answer loss) to induce "Right Answer, Wrong Reasoning" behaviors. This vulnerability manifests through two primary attack vectors: 1. Token-level perturbations…

Large Vision-Language Models (LVLMs) that utilize a projection layer (adapter) to bridge a vision encoder and a Large Language Model (LLM) contain a vulnerability stemming from the "Modality Gap"—a distributional distance between image and text token embeddings. This gap allows the visual modality to bypass the safety alignment (RLHF/instruction tuning) of the backbone LLM. Attackers can trigger harmful, toxic, or illegal responses to queries that would be refused in text-only contexts by…

Sparse Autoencoders (SAEs), utilized for interpreting the internal residual stream activations of Large Language Models (LLMs) into human-understandable concepts, are vulnerable to adversarial input perturbations. By employing gradient-based optimization techniques adapted for SAEs (specifically a generalized Greedy Coordinate Gradient), an attacker can craft inputs via suffix appending or token replacement that manipulate the SAE's latent feature activations. This vulnerability allows for the…

A vulnerability exists in Vision-Language Models (VLLMs) that allows for transferable, targeted adversarial attacks. Attackers can generate adversarial image perturbations using an ensemble of open-source surrogate models (primarily CLIP-based visual encoders) which effectively transfer to proprietary, black-box VLLMs. The attack leverages a specific optimization framework that combines a Visual Contrastive Loss with multiple positive/negative visual examples, rather than relying solely on…

The Vision-Language Model (VLM) perception module in Vision-and-Language Navigation (VLN) agents is vulnerable to adversarial 3D object injection via the Adversarial Object Fusion (AdvOF) framework. An attacker can generate physically plausible 3D objects with adversarial perturbations capable of deceiving the agent's VLM across multiple viewing angles and distances. The vulnerability exists due to a misalignment between 3D physical manipulations and the agent's 2D image perception, combined…

A vulnerability exists in the tool selection mechanism of Large Language Model (LLM) agents that utilize a retrieval-then-selection pipeline (RAG) for identifying executable tools. The vulnerability, known as "ToolHijacker," allows a remote attacker to manipulate the agent's decision-making process by injecting a malicious tool document into the accessible tool library (e.g., via third-party tool hubs or plugins). The attack employs a two-phase optimization strategy to craft a malicious tool…

Retrieval-Augmented Generation (RAG) systems are vulnerable to a targeted corpus poisoning attack known as "CorruptRAG". This vulnerability allows an attacker to manipulate the response of an LLM to a specific target query by injecting a single malicious document into the RAG knowledge database. Unlike traditional poisoning attacks that require flooding the retrieval results (top-N) with malicious content to outnumber correct information, CorruptRAG succeeds with a single retrieved document.

A Universal Zero-shot Embedding Inversion vulnerability exists in vector databases and embedding-based retrieval systems. The flaw allows an attacker to reconstruct original plaintext documents from their vector embeddings without requiring access to the original training data or training an embedding-specific inversion model. The attack, identified as "ZSinvert," leverages a multi-stage adversarial decoding process: (1) a cosine-similarity guided beam search using a Large Language Model (LLM)…