This paper introduces a new distribution model of RGB colors in RGB color images that can be easily breakable by LSB embedding. Regarding the RGB colors as the points of a 3-dimensional lattice space, we consider the noisiness of some special sets called the δ-cubes. The model is based on the symmetrical patterns of noise vectors in some of the comparable δ-cubes. Our new steganalytic technique based on the model, called by the color cube analysis, was capable to detect reliably the low-rate LSB embedding, even when it did not have any false detection, in our experiment.