Supply chain
Poisoning datasets built from the web: what was shown
A 2023 paper showed two practical ways to poison datasets that are assembled from web content. The weak point is the gap between when data is checked and when it is downloaded.
Last reviewed against Anthropic, UK AI Security Institute and arXiv. Sources
Many training sets are lists of links, not stored files. Whoever downloads them later gets whatever those links serve at that moment. The paper "Poisoning Web-Scale Training Datasets is Practical" set out to test that weakness [8].
Two attacks
Split-view and frontrunning
The authors, led by researchers including Nicholas Carlini, introduced two attacks and said they could poison 10 popular datasets [8].
Split-view poisoning
This exploits content that changes over time, so that the view a curator checked differs from what a later client downloads [8].
Frontrunning poisoning
This targets datasets that take periodic snapshots of crowd-sourced content such as Wikipedia, and needs only a time-limited window to inject malicious examples [8].
The numbers
Scale and cost
The paper states that about 0.01% of the LAION-400M or COYO-700M datasets could be poisoned for about $60 [8]. The authors notified the maintainers of each affected dataset and recommended several low-overhead defences [8].
Dated, but still relevant
The first version appeared on 20 February 2023 and the current version was revised on 6 May 2024 [8]. Check any dataset you use against its maintainers' current guidance, as protections may have changed since.
Why it matters to you
Dependencies you may not see
If a supplier or open source project trained on a crawled dataset, you inherit that dataset's exposure. The NCSC guidelines place supply chain security within secure development [6]. Knowing where your data comes from is the first step to managing that.
Ask these of any dataset you rely on:
- Is it stored, or is it a list of links fetched later?
- Does it include crowd-edited sources that can change between snapshots?
- Is there a way to confirm what you downloaded matches what was checked?

Keep reading
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Prevention
Practical controls to reduce data poisoning risk, drawn from OWASP and NCSC guidance: provenance, versioning, vetting and sandboxing.
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Detection
How to look for signs of poisoned data: output checks, adversarial testing, monitoring and why benchmarks alone are not enough.
Read the guideHow CyPro can help
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