Versatile AI Risk Assessment

AI threat catalogueModel and Training Data ManipulationDevelopment

Targeted Poisoning / Label Poisoning

Attackers tamper with a small, targeted portion of the training data, for example through wrong labels. Overall the model looks fine, but for specific cases chosen by the attacker it reliably makes the wrong call.

As of: July 2026 · Catalogue version 2026.07.17.3 · 4 mitigations · 11 verified sources

Description

In supervised learning, every training example carries a label such as 'fraud' or 'no fraud'. In targeted poisoning, the attacker rewrites these labels for a small subset or adds an inconspicuous trigger pattern to selected examples. The model then learns a hidden exception rule that only fires on the inputs the attacker cares about. Because overall accuracy stays normal, standard quality tests usually do not reveal the manipulation. Every place where data is labeled is a potential entry point: in-house teams, crowdsourcing, or external service providers. Even a small number of manipulated records can be enough.

Possible impact

The organization relies on a system that fails precisely in the cases that matter to the attacker, for example in fraud screening or access decisions. Such blind spots often go unnoticed for a long time and cause financial losses and liability questions. Reports and analyses also lose credibility because they build on corrupted decisions.

Example

An insurer has claim reports labeled by an external provider to train its fraud detection. An insider there consistently marks one particular type of fabricated claim as genuine. The finished model later waves this exact fraud pattern through automatically.

Recommended mitigations (4)

Every mitigation states its control type, effect, implementation level and the reason for the classification.

Framework mappings

Verified locations in OWASP, NIST AI RMF, MITRE ATLAS, the EU AI Act and further frameworks. The mappings are taxonomic, not evidence of compliance.

OWASP LLM Top 10 LLM04:2025NIST AI RMF Section 2.9 · NISTAML.012 · NISTAML.024MITRE ATLAS AML.T0020EU AI Act Article 53(1)(d) · Article 55(1)(a)BSI R17BIML BIML-LLM LLMtop10:6 · BIML78 assembly:2 · BIML78 data:6

Verified references (11)

Every reference states the framework, the exact location and the publishing organisation.

More entries from the topic group Model and Training Data Manipulation.

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Cite this entry

For reports, policies or internal documents; the link leads directly to this entry.

“Targeted Poisoning / Label Poisoning”. Versatile AI Risk Assessment, AI threat catalogue, as of July 2026.
https://www.versatile-ai-risk-assessment.com/en/wissensbasis/threats/targeted-label-poisoning/

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