  We consider a sensor network focused on target localization, where sensors
measure the signal strength emitted from the target. Each measurement is
quantized to one bit and sent to the fusion center. A general attack is
considered at some sensors that attempts to cause the fusion center to produce
an inaccurate estimation of the target location with a large mean-square-error.
The attack is a combination of man-in-the-middle, hacking, and spoofing attacks
that can effectively change both signals going into and coming out of the
sensor nodes in a realistic manner. We show that the essential effect of
attacks is to alter the estimated distance between the target and each attacked
sensor to a different extent, giving rise to a geometric inconsistency among
the attacked and unattacked sensors. Hence, with the help of two secure
sensors, a class of detectors are proposed to detect the attacked sensors by
scrutinizing the existence of the geometric inconsistency. We show that the
false alarm and miss probabilities of the proposed detectors decrease
exponentially as the number of measurement samples increases, which implies
that for sufficiently large number of samples, the proposed detectors can
identify the attacked and unattacked sensors with any required accuracy.
