Today, for many applications, it is increasingly necessary to secure multimedia data. The use of full encryption has proved effective and secure, but it does not always allow a trade-off between security and other requirements. Image obscuration then presents itself as a possible and welcome solution, preserving the integrity of the multimedia data while obscuring its content. In 2021, Aprilpyone and Kiya [1] proposed a block-wise bit flipping image obscuration method, using a secret key which permits the original image to be obscured and secret, while being reversible in order to recover it. However, this method presents an exploitable weakness which can be profitable for an attack. In this paper, we present an approach to attack obscured images by bit flipping, in order to reconstruct the original image without any knowledge of the secret key.