Getting into "IBS" Hyderabad is not tough at all. In fact, their admissions team will keep calling you until you give them a straight and strict answer stating that you are not willing to take admission to IBS but rather to the Indian School of Business (ISB). Generally, people get confused between the two IBS and the ISB.
The selection criteria for IBS is, you have to take any one of the exams like CAT or XAT or NMAT or IBSAT Scores, and once you clear the cut-off you have to go through a personal interview and then a group discussion, with good academic scores.