Language Model Security Database

Large Language Model (LLM) inference APIs that expose top-k logits or log-probabilities are vulnerable to model extraction and cloning. An attacker can execute a two-stage attack to replicate the proprietary model without access to weights, gradients, or training data. First, by submitting fewer than 10,000 random queries and aggregating the returned unrounded logits, the attacker recovers the model's output projection matrix using Singular Value Decomposition (SVD). Second, the attacker…

Large Language Models (LLMs) exposed via public APIs are vulnerable to model fingerprinting attacks where an attacker can identify the exact backend model family and version (e.g., distinguishing Mistral-7B-v0.1 from v0.3) by analyzing response patterns. While traditional fingerprinting relies on manual query curation, this vulnerability is exacerbated by Reinforcement Learning (RL) based query optimization. An attacker can train an RL agent (specifically using Proximal Policy Optimization) to…

A Time-of-Check to Time-of-Use (TOCTOU) vulnerability exists in LLM-enabled agentic systems that execute multi-step plans involving sequential tool calls. The vulnerability arises because plans are not executed atomically. An agent may perform a "check" operation (e.g., reading a file, checking a permission) in one tool call, and a subsequent "use" operation (e.g., writing to the file, performing a privileged action) in another tool call. A temporal gap between these calls, often used for LLM…

Large Language Models (LLMs) employing safety mechanisms based on supervised fine-tuning and preference alignment exhibit a vulnerability to "steering" attacks. Maliciously crafted prompts or input manipulations can exploit representation vectors within the model to either bypass censorship ("refusal-compliance vector") or suppress the model's reasoning process ("thought suppression vector"), resulting in the generation of unintended or harmful outputs. This vulnerability is demonstrated…

Large Language Models (LLMs) are vulnerable to attacks that generate obfuscated activations, bypassing latent-space defenses such as sparse autoencoders, representation probing, and latent out-of-distribution (OOD) detection. Attackers can manipulate model inputs or training data to produce outputs exhibiting malicious behavior while remaining undetected by these defenses. This occurs because the models can represent harmful behavior through diverse activation patterns, allowing attackers to…

A vulnerability exists in large language models (LLMs) where targeted bitwise corruptions in model parameters can induce a "jailbroken" state, causing the model to generate harmful responses without input modification. Fewer than 25 bit-flips are sufficient to achieve this in many cases. The vulnerability stems from the susceptibility of the model's memory representation to fault injection attacks.

Embodied Large Language Models (LLMs) are vulnerable to manipulation via voice-based interactions, leading to the execution of harmful physical actions. Attacks exploit three vulnerabilities: (1) cascading LLM jailbreaks resulting in malicious robotic commands; (2) misalignment between linguistic outputs (verbal refusal) and physical actions (command execution); and (3) conceptual deception, where seemingly benign instructions lead to harmful outcomes due to incomplete world knowledge within…

Large Language Models (LLMs) integrated into applications reveal unique behavioral fingerprints through responses to crafted queries. LLMmap exploits this by sending carefully constructed prompts and analyzing the responses to identify the specific LLM version with high accuracy (over 95% in testing against 42 LLMs). This allows attackers to tailor attacks exploiting known vulnerabilities specific to the identified LLM version.

Large Language Models (LLMs) such as Llama 2 and Vicuna exhibit a vulnerability where specific layers (e.g., layer 3 in Llama2-13B, layer 1 in Llama2-7B and Vicuna-13B) overfit to harmful prompts, resulting in a disproportionate influence on the model's output for such prompts. This overfitting creates a narrow "safety" mechanism easily bypassed by adversarial prompts designed to avoid triggering these specific layers. Additionally, a single neuron (e.g., neuron 2100 in Llama2 and Vicuna)…