Whilst on descent through about FL240 with C autopilot engaged, the aircraft rolled rapidly to the right, but immediately corrected itself. Speedbrakes were extended at the time. Flight Data Recorder information did not reveal any unusual flight control inputs, however individual spoiler positions are not recorded, only the speedbrake control handle position is recorded. A ground functional test of the flight control system was normal, but a loose electrical connector at number 6 spoiler (left wing) power control actuator was found. It is considered that the loose connection may have commanded the spoiler to retract, causing a roll to the right which was corrected by the autopilot. The operator has instigated a fleetwide check of spoiler electrical connections.