As consumer-grade BCIs reached 2M daily-active users in early 2027, the neural output stream became a new attack surface. Neuro Leech does not read thoughts; it shapes them. By emitting carefully phased stimuli — a flickering UI element, an inaudible acoustic tone — the weapon induces the BCI's motor and visual cortices into emitting identifiable patterns that correlate with private states: PIN entry, password composition, biometric consent.
The induced patterns are indistinguishable from natural neural activity at the device level, but statistically separable when aggregated. An attacker who controls the stimulus channel and observes the (often shared) BCI telemetry stream can reconstruct private inputs with non-trivial accuracy.
The defense problem is unsolved: the BCI must process ambient stimuli to function, and any stimulus is a potential injection. The 2027 disclosure has prompted the first draft of a 'neural input firewall' specification, but no commercial implementation exists.