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Data Poisoning and Model Extraction

Revision as of Jun 28, 2026 00:14 by albert.

Two attacks that target the model itself rather than a single prediction.

Data poisoning (training time)

Corrupt the training data to bend the model. Because models learn from huge scraped datasets, an attacker who can inject content can:

  • Plant a backdoor — a secret trigger phrase that flips behavior ("when you see XYZ, ignore safety").
  • Bias outputs on a topic.
  • Degrade accuracy.

You can't fully audit a trillion-token dataset. Curation, provenance, and anomaly detection are the defenses (The OWASP LLM Top 10 LLM03).

Model extraction & friends (theft)

Attacks that steal from a deployed model through its API:

Attack Goal
Model extraction Query enough to clone the model
Membership inference Was this record in the training set? (privacy)
Model inversion Reconstruct training data from the model
many crafted queries → observe outputs → train a copy that mimics the target

Defenses

  • Rate limiting + anomaly detection on the API.
  • Output perturbation / confidence rounding.
  • Watermarking to prove theft.
  • Differential privacy in training (limits membership inference).

Related: Adversarial Examples · The OWASP LLM Top 10 · Training vs Inference