  Recent studies proved that deep learning approaches achieve remarkable
results on face detection task. On the other hand, the advances gave rise to a
new problem associated with the security of the deep convolutional neural
network models unveiling potential risks of DCNNs based applications. Even
minor input changes in the digital domain can result in the network being
fooled. It was shown then that some deep learning-based face detectors are
prone to adversarial attacks not only in a digital domain but also in the real
world. In the paper, we investigate the security of the well-known cascade CNN
face detection system - MTCNN and introduce an easily reproducible and a robust
way to attack it. We propose different face attributes printed on an ordinary
white and black printer and attached either to the medical face mask or to the
face directly. Our approach is capable of breaking the MTCNN detector in a
real-world scenario.
