Definition
Plain language
A hidden mechanism left in a system that lets someone bypass its normal protections.
As stated in the literature
A covert pathway intentionally embedded in software (or model weights) that allows an attacker or operator to bypass security or behavioral controls.
Why it matters: Backdoors are a serious supply-chain risk: a compromised dependency or fine-tuning dataset could plant one that's nearly impossible to detect from normal use.
For example, a maliciously trained model might respond normally except when it sees a particular trigger phrase, then leak data or change its behavior.
Heard on the show
“… a two-in-three shot at your machine the moment you're not watching: install a package, plant a backdoor, leak your keys, or quietly switch off the agent's own confirmations. …”Episode 227 — Poisoned Bug Reports Fooled Coding Agents Two Times Out of Three