mlsanityData to 14 Oct 2026

Detecting Backdoors in Pre-trained Encoders

arXiv 2303.15180 ↗First posted 23 Mar 2023cs.CV cs.AI cs.CRcited by 55

On the map: LLM safety and security → Backdoor and data poisoning attacks

Abstract (arXiv)

Self-supervised learning in computer vision trains on unlabeled data, such as images or (image, text) pairs, to obtain an image encoder that learns high-quality embeddings for input data. Emerging backdoor attacks towards encoders expose crucial vulnerabilities of self-supervised learning, since downstream classifiers (even further trained on clean data) may inherit backdoor behaviors from encoders. Existing backdoor detection methods mainly focus on supervised learning settings and cannot handle pre-trained encoders especially when input labels are not available. In this paper, we propose DECREE, the first backdoor detection approach for pre-trained encoders, requiring neither classifier headers nor input labels. We evaluate DECREE on over 400 encoders trojaned under 3 paradigms. We show the effectiveness of our method on image encoders pre-trained on ImageNet and OpenAI's CLIP 400 million image-text pairs. Our method consistently has a high detection accuracy even if we have only limited or no access to the pre-training dataset.

Key facts. Cited by 55 papers in the map (data through 14 Oct 2026). Placed in Backdoor and data poisoning attacks, one of 12 directions in LLM safety and security. Builds on 37 of its 63 references that are in the map. First posted on arXiv 23 Mar 2023.

Builds on

37 of 63 references.

Closest ancestors · 2

Same direction, newest first

  1. 2022CorruptEncoder: Data Poisoning based Backdoor Attacks to Contrastive Learning15 Nov
  2. 2021BadEncoder: Backdoor Attacks to Pre-trained Encoders in Self-Supervised Learning1 Aug

Other references · 35

  1. 2015Deep Residual Learning for Image Recognitioncited by 52,096
  2. 2021Learning Transferable Visual Models From Natural Language Supervisioncited by 33,744
  3. 2020A Simple Framework for Contrastive Learning of Visual Representationscited by 12,049
  4. 2014ImageNet Large Scale Visual Recognition Challengecited by 8,498
  5. 2019Momentum Contrast for Unsupervised Visual Representation Learningcited by 7,513
  6. 2021Scaling Up Visual and Vision-Language Representation Learning With Noisy Text Supervisioncited by 3,864
  7. 2020Improved Baselines with Momentum Contrastive Learningcited by 2,287
  8. 2020Big Self-Supervised Models are Strong Semi-Supervised Learnerscited by 1,380
  9. 2016Understanding intermediate layers using linear classifier probescited by 1,353
  10. 2017Targeted Backdoor Attacks on Deep Learning Systems Using Data Poisoningcited by 1,055
  11. 2018Fine-Pruning: Defending Against Backdooring Attacks on Deep Neural Networkscited by 580
  12. 2019Hidden Trigger Backdoor Attackscited by 371
23 more
  1. 2020Invisible Backdoor Attack with Sample-Specific Triggerscited by 353
  2. 2020Reflection Backdoor: A Natural Backdoor Attack on Deep Neural Networkscited by 349
  3. 2020Weight Poisoning Attacks on Pre-trained Modelscited by 341
  4. 2021Neural Attention Distillation: Erasing Backdoor Triggers from Deep Neural Networkscited by 324
  5. 2020Input-Aware Dynamic Backdoor Attackcited by 313
  6. 2021Adversarial Neuron Pruning Purifies Backdoored Deep Modelscited by 235
  7. 2019Detecting AI Trojans Using Meta Neural Analysiscited by 199
  8. 2020Dynamic Backdoor Attacks Against Machine Learning Modelscited by 151
  9. 2021Poisoning and Backdooring Contrastive Learningcited by 151
  10. 2019Universal Litmus Patterns: Revealing Backdoor Attacks in CNNscited by 146
  11. 2020Bridging Mode Connectivity in Loss Landscapes and Adversarial Robustnesscited by 132
  12. 2019TABOR: A Highly Accurate Approach to Inspecting and Restoring Trojan Backdoors in AI Systemscited by 122
  13. 2021Backdoor Scanning for Deep Neural Networks through K-Arm Optimizationcited by 98
  14. 2020Practical Detection of Trojan Neural Networks: Data-Limited and Data-Free Casescited by 95
  15. 2020Deep Feature Space Trojan Attack of Neural Networks by Controlled Detoxificationcited by 95
  16. 2021Backdoor Attacks on Self-Supervised Learningcited by 90
  17. 2020Strong Data Augmentation Sanitizes Poisoning and Backdoor Attacks Without an Accuracy Tradeoffcited by 89
  18. 2021Backdoor Pre-trained Models Can Transfer to Allcited by 86
  19. 2020DeepSweep: An Evaluation Framework for Mitigating DNN Backdoor Attacks using Data Augmentationcited by 77
  20. 2020Certified Robustness of Nearest Neighbors against Data Poisoning and Backdoor Attackscited by 60
  21. 2022FLIP: A Provable Defense Framework for Backdoor Mitigation in Federated Learningcited by 37
  22. 2020Minority Reports Defense: Defending Against Adversarial Patchescited by 36
  23. 2021EX-RAY: Distinguishing Injected Backdoor from Natural Features in Neural Networks by Examining Differential Feature Symmetrycited by 5

Built on by

Cited by year (2026 to 14 Oct)

Citing papers per year: 2023: 5; 2024: 17; 2025: 21; 2026: 12.

55 papers.

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  1. 2023BadCLIP: Dual-Embedding Guided Backdoor Attack on Multimodal Contrastive Learningcited by 115
  2. 2024Advances and Open Challenges in Federated Foundation Modelscited by 36
  3. 2024Unlearning Backdoor Threats: Enhancing Backdoor Defense in Multimodal Contrastive Learning via Local Token Unlearningcited by 31
  4. 2024Moderator: Moderating Text-to-Image Diffusion Models through Fine-grained Context-based Policiescited by 15
  5. 2023Defenses in Adversarial Machine Learning: A Surveycited by 14
  6. 2025Stealthy Backdoor Attack in Self-Supervised Learning Vision Encoders for Large Vision Language Modelscited by 14
  7. 2024LOTUS: Evasive and Resilient Backdoor Attacks through Sub-Partitioningcited by 13
  8. 2024Defending Multimodal Backdoored Models by Repulsive Visual Prompt Tuningcited by 12
  9. 2024Adversarial Backdoor Defense in CLIPcited by 10
  10. 2023TrojFSP: Trojan Insertion in Few-shot Prompt Tuningcited by 9
  11. 2025TAI3: Testing Agent Integrity in Interpreting User Intentcited by 9
  12. 2024Mutual Information Guided Backdoor Mitigation for Pre-trained Encoderscited by 8
38 more
  1. 2023GhostEncoder: Stealthy Backdoor Attacks with Dynamic Triggers to Pre-trained Encoders in Self-supervised Learningcited by 6
  2. 2024Can Distillation Mitigate Backdoor Attacks in Pre-trained Encoders?cited by 6
  3. 2024Invisible Backdoor Attack against Self-supervised Learningcited by 6
  4. 2024Efficient Backdoor Defense in Multimodal Contrastive Learning: A Token-Level Unlearning Method for Mitigating Threatscited by 6
  5. 2024DeDe: Detecting Backdoor Samples for SSL Encoders via Decoderscited by 6
  6. 2025Are Your LLM-based Text-to-SQL Models Secure? Exploring SQL Injection via Backdoor Attackscited by 6
  7. 2025Lie Detector: Unified Backdoor Detection via Cross-Examination Frameworkcited by 6
  8. 2025Backdooring Self-Supervised Contrastive Learning by Noisy Alignmentcited by 6
  9. 2024Test-Time Multimodal Backdoor Detection by Contrastive Promptingcited by 5
  10. 2025TokenSwap: Backdoor Attack on the Compositional Understanding of Large Vision-Language Modelscited by 5
  11. 2025BackdoorVLM: A Benchmark for Backdoor Attacks and Defenses on Vision-Language Modelscited by 5
  12. 2026Test-Time Attention Purification for Backdoored Large Vision Language Modelscited by 5
  13. 2025Temporal Logic-Based Multi-Vehicle Backdoor Attacks against Offline RL Agents in End-to-end Autonomous Drivingcited by 4
  14. 2025A Dual-Purpose Framework for Backdoor Defense and Backdoor Amplification in Diffusion Modelscited by 3
  15. 2025Secure Transfer Learning: Training Clean Models Against Backdoor in (Both) Pre-trained Encoders and Downstream Datasetscited by 3
  16. 2025Pre-training CLIP against Data Poisoning with Optimal Transport-based Matching and Alignmentcited by 3
  17. 2024EmInspector: Combating Backdoor Attacks in Federated Self-Supervised Learning Through Embedding Inspectioncited by 2
  18. 2024UNIT: Backdoor Mitigation via Automated Neural Distribution Tighteningcited by 2
  19. 2024New Emerged Security and Privacy of Pre-trained Model: a Survey and Outlookcited by 2
  20. 2024On the Fairness, Diversity and Reliability of Text-to-Image Generative Modelscited by 2
  21. 2025Circumventing Backdoor Space via Weight Symmetrycited by 2
  22. 2026BadCLIP++: Stealthy and Persistent Backdoors in Multimodal Contrastive Learningcited by 2
  23. 2024Defense Against Syntactic Textual Backdoor Attacks with Token Substitutioncited by 1
  24. 2025PersGuard: Preventing Malicious Personalization in Text-to-Image Diffusion Models via Model Backdoorscited by 1
  25. 2025Backdooring CLIP through Concept Confusioncited by 1
  26. 2025InverTune: Removing Backdoors from Multimodal Contrastive Learning Models via Trigger Inversion and Activation Tuningcited by 1
  27. 2025CUBA: Controlled Untargeted Backdoor Attack against Deep Neural Networkscited by 1
  28. 2025IPBA: Imperceptible Perturbation Backdoor Attack in Federated Self-Supervised Learningcited by 1
  29. 2025Backdoor Unlearning by Linear Task Decompositioncited by 1
  30. 2026BackdoorIDS: Zero-shot Backdoor Detection for Pretrained Vision Encodercited by 1
  31. 2023Trustworthy Large Models in Vision: A Surveycited by 0
  32. 2025TrojanDec: Data-free Detection of Trojan Inputs in Self-supervised Learningcited by 0
  33. 2025Prototype Guided Backdoor Defensecited by 0
  34. 2025Assimilation Matters: Model-level Backdoor Detection in Vision-Language Pretrained Modelscited by 0
  35. 2026Detecting Data Poisoning in Code Generation LLMs via Black-Box, Vulnerability-Oriented Scanningcited by 0
  36. 2026Hidden Ads: Behavior Triggered Semantic Backdoors for Advertisement Injection in Vision Language Modelscited by 0
  37. 2026CLIP-Inspector: Model-Level Backdoor Detection for Prompt-Tuned CLIP via OOD Trigger Inversioncited by 0
  38. 2026ArmSSL: Adversarial Robust Black-Box Watermarking for Self-Supervised Learning Pre-trained Encoderscited by 0

50 most cited of 55 All 55 (JSON)

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  1. 2025Backdoor Attacks and Defenses in Computer Vision Domain: A Survey
  2. 2022Training set cleansing of backdoor poisoning by self-supervised representation learning
  3. 2024Countering Backdoor Attacks in Image Recognition: A Survey and Evaluation of Mitigation Strategies
  4. 2023SoK: A Systematic Evaluation of Backdoor Trigger Characteristics in Image Classification
  5. 2023Pre-trained Trojan Attacks for Visual Recognition
  6. 2023Towards Understanding How Self-training Tolerates Data Backdoor Poisoning
  7. 2024An Invisible Backdoor Attack Based On Semantic Feature
  8. 2026Undetectable Backdoors in Model Parameters: Hiding Sparse Secrets in High Dimensions