MirrorDrift demonstrates that mirror reflections are a stealthy, injection-free alternative to signal-injection-based LiDAR attacks. Using a planar mirror equipped with an actuation mechanism, ghost points are created by reflecting existing laser pulses, systematically biasing scan matching correspondences without emitting any signal. The attack optimizes mirror placement, alignment, and actuation to maximize localization error — achieving a 6.1× increase in mean pose error over random placement, inducing up to 6.03 m of localization error, and degrading three SLAM systems to 2.29–3.31 m average trajectory error.