OWASP Top 10 for LLMs
LLM04

Data and Model Poisoning

Attackers corrupt training, fine-tuning, or retrieval data to plant backdoors or bias.

Poisoning manipulates the data a model learns from or retrieves. In training and fine-tuning it can plant trigger phrases or skew behavior; in RAG it can steer retrieval toward attacker-chosen content. Because the effect is baked into weights or the index, it is hard to detect after the fact.

How it shows up

  • Crafted samples in a crowd-sourced dataset create a trigger phrase that flips classifier output.
  • Documents engineered to rank highly poison a vector store used for retrieval.
  • A fine-tuning run inherits bias from an unvetted data source.

Mitigations

  • Validate and curate data sources; track provenance and integrity.
  • Monitor for anomalous trigger phrases and behavioral drift.
  • Control write access to vector stores and retrieval corpora.
  • Use robust training techniques and hold-out evaluations to detect poisoning.

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