The wireless technology is inherently susceptible to many types of attacks. There are few studies that have investigated the collision attacks. However, to the best of our knowledge, there is no prior work on investigating the consequences of the collision attacks on performance of the wireless networks. Hence, this work proposes a new module specifically for NS2 simulator which is capable of implementing and measuring the impact of the collision attacks on performance of the functional wireless networks. With the same conditions, we further design a testbed to measure the effectiveness of the collision attacks in real networks. Finally, in order to prove the accuracy of the proposed module, its results are compared with the results from the testbed. The purpose is to accurately determine the impact of the collision attacks which is essential for evaluation and testing the potential defense appliances against the attack. The results signify the extensive impact of the attack on disrupting the normal operation of the wireless networks.