LUMIA: Linear probing for Unimodal and MultiModal Membership Inference Attacks leveraging internal LLM states
On the map: LLM safety and security → Membership inference attacks
Abstract (arXiv)
Large Language Models (LLMs) are increasingly used in a variety of applications, but concerns around membership inference have grown in parallel. Previous efforts focus on black-to-grey-box models, thus neglecting the potential benefit from internal LLM information. To address this, we propose the use of Linear Probes (LPs) as a method to detect Membership Inference Attacks (MIAs) by examining internal activations of LLMs. Our approach, dubbed LUMIA, applies LPs layer-by-layer to get fine-grained data on the model inner workings. We test this method across several model architectures, sizes and datasets, including unimodal and multimodal tasks. In unimodal MIA, LUMIA achieves an average gain of 15.71 % in Area Under the Curve (AUC) over previous techniques. Remarkably, LUMIA reaches AUC>60% in 65.33% of cases -- an increment of 46.80% against the state of the art. Furthermore, our approach reveals key insights, such as the model layers where MIAs are most detectable. In multimodal models, LPs indicate that visual inputs can significantly contribute to detect MIAs -- AUC>60% is reached in 85.90% of experiments.
Key facts. Cited by 10 papers in the map (data through 13 Oct 2026). Placed in Membership inference attacks, one of 12 directions in LLM safety and security. Builds on 39 of its 56 references that are in the map. First posted on arXiv 29 Nov 2024.
Builds on
39 of 56 references.
Closest ancestors · 6
Same direction, newest first
- 2024Detecting Training Data of Large Language Models via Expectation Maximization10 Oct
- 2024Membership Inference Attacks Cannot Prove that a Model Was Trained On Your Data29 Sep
- 2024Blind Baselines Beat Membership Inference Attacks for Foundation Models23 Jun
- 2024Do Membership Inference Attacks Work on Large Language Models?12 Feb
- 2023Did the Neurons Read your Book? Document-level Membership Inference for Large Language Models23 Oct
- 2021Membership Inference Attacks From First Principles7 Dec
Other references · 33
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21 more
- 2016Understanding intermediate layers using linear classifier probescited by 1,313
- 2024How Far Are We to GPT-4V? Closing the Gap to Commercial Multimodal Models with Open-Source Suitescited by 1,041
- 2019Compressive Transformers for Long-Range Sequence Modellingcited by 707
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- 2020TextCaps: a Dataset for Image Captioning with Reading Comprehensioncited by 398
- 2023Detecting Pretraining Data from Large Language Modelscited by 383
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- 2024Magpie: Alignment Data Synthesis from Scratch by Prompting Aligned LLMs with Nothingcited by 342
- 2019White-box vs Black-box: Bayes Optimal Strategies for Membership Inferencecited by 270
- 2021IconQA: A New Benchmark for Abstract Diagram Understanding and Visual Language Reasoningcited by 264
- 2024VITA: Towards Open-Source Interactive Omni Multimodal LLMcited by 172
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- 2024Black-Box Access is Insufficient for Rigorous AI Auditscited by 125
- 2024On Protecting the Data Privacy of Large Language Models (LLMs): A Surveycited by 94
- 2024Get my drift? Catching LLM Task Drift with Activation Deltascited by 71
- 2024Do LLMs Know about Hallucination? An Empirical Investigation of LLM's Hidden Statescited by 52
- 2024Probing Language Models for Pre-training Data Detectioncited by 24
- 2024Cross-Modal Projection in Multimodal LLMs Doesn't Really Project Visual Attributes to Textual Spacecited by 21
- 2023Energy and Carbon Considerations of Fine-Tuning BERTcited by 11
Built on by
Citing papers per year: 2025: 5; 2026: 5.
10 papers.
- 2025Membership Inference Attacks on Large-Scale Models: A Surveycited by 17
- 2026G-Drift MIA: Membership Inference via Gradient-Induced Feature Drift in LLMscited by 7
- 2025Black-Box Membership Inference Attack for LVLMs via Prior Knowledge-Calibrated Memory Probingcited by 4
- 2025SMA: Who Said That? Auditing Membership Leakage in Semi-Black-box RAG Controllingcited by 3
- 2025Data Provenance Auditing of Fine-Tuned Large Language Models with a Text-Preserving Techniquecited by 3
- 2025MrM: Black-Box Membership Inference Attacks against Multimodal RAG Systemscited by 2
- 2026What Hard Tokens Reveal: Exploiting Low-confidence Tokens for Membership Inference Attacks against Large Language Modelscited by 0
- 2026SERSEM: Selective Entropy-Weighted Scoring for Membership Inference in Code Language Modelscited by 0
- 2026DistractMIA: Black-Box Membership Inference on Vision-Language Models via Semantic Distractioncited by 0
- 2026MemCatalyst: Amplifying Data Auditing on Vision-Language Models via Data Poisoningcited by 0
- 2026MemCatalyst: Amplifying Data Auditing on Vision-Language Models via Data Poisoning18 Aug 2026
- 2026DistractMIA: Black-Box Membership Inference on Vision-Language Models via Semantic Distraction12 May 2026
- 2026SERSEM: Selective Entropy-Weighted Scoring for Membership Inference in Code Language Models1 Apr 2026
- 2026G-Drift MIA: Membership Inference via Gradient-Induced Feature Drift in LLMs1 Apr 2026
- 2026What Hard Tokens Reveal: Exploiting Low-confidence Tokens for Membership Inference Attacks against Large Language Models27 Jan 2026
- 2025Black-Box Membership Inference Attack for LVLMs via Prior Knowledge-Calibrated Memory Probing3 Nov 2025
- 2025Data Provenance Auditing of Fine-Tuned Large Language Models with a Text-Preserving Technique7 Oct 2025
- 2025SMA: Who Said That? Auditing Membership Leakage in Semi-Black-box RAG Controlling12 Aug 2025
- 2025MrM: Black-Box Membership Inference Attacks against Multimodal RAG Systems9 Jun 2025
- 2025Membership Inference Attacks on Large-Scale Models: A Survey25 Mar 2025
Similar, not cited
Close in wording, no citation either way
- 2026Membership Inference on LLMs in the Wild
- 2025Exploring the limits of strong membership inference attacks on large language models
- 2025Automatic Calibration for Membership Inference Attack on Large Language Models
- 2024A Statistical and Multi-Perspective Revisiting of the Membership Inference Attack in Large Language Models
- 2026AttenMIA: LLM Membership Inference Attack through Attention Signals
- 2024Scaling Up Membership Inference: When and How Attacks Succeed on Large Language Models
- 2025In-Context Probing for Membership Inference in Fine-Tuned Language Models
- 2025FiMMIA: scaling semantic perturbation-based membership inference across modalities